教你用Java实现一个简单的代码生成器

前言

逆向工程从数据库表直接生成代码，是日常开发中常用的敏捷开发手段，常见的例如：mybatis-plus的代码生成器等

为什么要自己写代码生成器呢？MP的生成器不香吗？香！

但是自己写的工具用起来最顺手，可以随意扩展，想怎么玩就怎么玩，只要自己有想法，玩出花来都没问题，当然了，能力有限，现在还只能实现简单版本，更多骚操作自己发挥！

思路：

1、建立jdbc连接，执行查询sql，获取表结构信息。

2、在指定的路径上创建文件。

3、按照我们的布局排版要求，根据表结构信息拼接文件的内容。

4、将字符输出到文件中。

以上即可完成一个文件的自动生成

编码　

通用部分

几个内部工具类

file工具类：创建、读取文件

字符串工具类：驼峰标识、下划线互转，首字母大写，数据库字段类型转java类型等

jdbc连接：连接数据库

表注释、表结构信息实体类、执行sql获取表结构信息的方法

表结构信息

private String columnName;//字段名
private String dataType;//字段类型
private String columnComment;//字段注释
private String columnKey;//主键
private String extra;//主键类型

mysql查询表注释、表字段信息使用的是

表字段信息

SELECT
    column_name,
    data_type,
    column_comment,
    column_key,
    extra 
FROM
    information_schema.COLUMNS 
WHERE
    table_schema = (
    SELECT DATABASE
    ()) 
    AND table_name =?

表注释

SELECT
    table_comment 
FROM
    information_schema.TABLES 
WHERE
    table_schema = (
    SELECT DATABASE
    ()) 
    AND table_name =?

需要支持其他数据库类型的，自己调整就好了，例如oracle获取表注释、表结构sql如下：

-- 表、表注释
SELECT
    t.table_name,
    t1.comments 
FROM
    user_tables t
    JOIN user_tab_comments t1 ON t.table_name = t1.table_name;

-- 表字段、字段注释
SELECT
    t.table_name,
    c.column_name,
    c.data_type,
    cc.comments 
FROM
    USER_TAB_COLUMNS c
    JOIN user_tables t ON c.table_name = t.table_name
    JOIN user_col_comments cc ON cc.table_name = t.table_name 
WHERE
    cc.column_name = c.column_name;

另外，数据连接、基础路径的配置也是一样

/**
 * 数据连接相关，需要手动设置
 */
private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";
private static final String USERNAME = "root";
private static final String PASSWORD = "123456";
private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";
/**
 * 基础路径，需要手动设置
 */
private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置
private String filePackage = basePackage + "sys\\";//文件所在包位置

2.0版本多一个模板文件路径

private String tlfPath = System.getProperty("user.dir") + "\\src\\main\\resources\\tlf\\";//模板文件位置

main函数也一样，调用构造参数，传入表名，调用入口函数

public static void main(String[] args) {
//        String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};
    String[] tables = {"tb_user"};
    for (String table : tables) {
        String msg = new AutoGenerator(table).create();
        System.out.println(msg);
    }
}

V1.0版本

AutoGenerator，1.0版本采用原始的在代码拼接字符串，然后创建文件将字符串输出的方法，比较原始但个人觉得可玩性较高

几个创建方法，就拿实体类来举例

/**
 * 创建pojo实体类
 */
private void createPojo(List tableInfos) {
    //创建文件
    File file = FileUtil.createFile(filePath + "pojo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ".java");
    
    //拼接文件内容
    StringBuffer stringBuffer = new StringBuffer();
    stringBuffer.append(
            "package " + filePackage.replaceAll("\\\\", ".") + "pojo;\n" +
                    "\n" +
                    "import lombok.Data;\n" +
                    "import javax.persistence.*;\n" +
                    "import java.io.Serializable;\n" +
                    "import java.util.Date;\n" +
                    "\n" +
                    "@Entity\n" +
                    "@Table(name = \"" + tableName + "\")\n" +
                    "@Data\n" +
                    "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + " implements Serializable {\n"
    );
    //遍历设置属性
    for (TableInfo tableInfo : tableInfos) {
        //主键
        if ("PRI".equals(tableInfo.getColumnKey())) {
            stringBuffer.append("    @Id\n");
        }
        //自增
        if ("auto_increment".equals(tableInfo.getExtra())) {
            stringBuffer.append("    @GeneratedValue(strategy= GenerationType.IDENTITY)\n");
        }
        stringBuffer.append("    private ").append(StringUtil.typeMapping(tableInfo.getDataType())).append(" ").append(StringUtil.camelCaseName(tableInfo.getColumnName())).append(";//").append(tableInfo.getColumnComment()).append("\n\n");
    }
    stringBuffer.append("}");
    
    //写入文件内容
    FileUtil.fileWriter(file, stringBuffer);
}

其他的也一样，无非就：创建文件、拼接文件内容、输出文件内容

入口函数，供main函数直接调用

/**
 * 快速创建，供外部调用，调用之前先设置一下项目的基础路径
 */
private String create() {
    System.out.println("生成路径位置：" + filePath);

    //获取表信息
    List tableInfo = getTableInfo();

    //开始生成代码
    createPojo(tableInfo);
    createVo(tableInfo);
    createRepository(tableInfo);
    createService(tableInfo);
    createController(tableInfo);

    return tableName + " 后台代码生成完毕！";
}

V2.0版本

AutoGeneratorPlus，2.0版本升级了，设置了模板文件、文件内容的字符串从模板读取，再根据关键字替换参数，最后再输出到创建的文件中，这个版本就比较好理解，大部分的代码生成器也都这样干

需要先定义模板文件（文件名后缀无所谓，自己随便定义），拿entity来举例

package cn.huanzi.qch.baseadmin.sys.${entityToLowerCase}.pojo;

import lombok.Data;
import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;

/**
 * ${tableComment} 实体类
 *
 * ${author}
 * ${date}
 */
@Entity
@Table(name = "${tableName}")
@Data
public class ${entity} implements Serializable {
  #for
    #ifPri
    #ifAutoIncrement
    private ${tableInfo.dataType} ${tableInfo.columnName};//${tableInfo.columnComment}
  #end
}

${}，用于取参数，替换成我们的值

#for、#if，循环遍历表字段以及判断是否为主键、是否主键自增

各种关键字随便定义，我们在读取模板文件处理时能对上就行

文件内容处理

/**
 * 读取模板，设置内容，生成文件
 * @param templatePath 模板文件路径
 * @param outputFile 文件生成路径
 * @param tableInfos 表字段信息
 * @param customParameter 自定义参数
 */
private void writer(String templatePath, String outputFile,List tableInfos,Map customParameter){
    //主键
    TableInfo prikey = new TableInfo();

    //for循环标识
    boolean forFlag = false;
    StringBuilder forContent = new StringBuilder();

    //驼峰标识映射后的表名
    String replacement = StringUtil.captureName(StringUtil.camelCaseName(tableName));

    //遍历属性
    for (TableInfo tableInfo : tableInfos) {
        //主键
        if ("PRI".equals(tableInfo.getColumnKey())) {
            prikey = tableInfo;
            break;
        }
    }

    try(FileReader fileReader = new FileReader(templatePath);
        BufferedReader reader = new BufferedReader(fileReader)) {
        //生成文件
        File file = FileUtil.createFile(outputFile);
        StringBuffer stringBuffer = new StringBuffer();

        //读取模板文件，拼接文件内容
        Object[] lines = reader.lines().toArray();
        for (Object o : lines) {
            String line = String.valueOf(o);

            /* 设置值 */

            //${tableName} 表名称，例如：tb_user
            if(line.contains("${tableName}")){
                line = line.replaceAll("\\$\\{tableName}", tableName);
            }

            //${tableComment} 表注释，例如：tb_user
            if(line.contains("${tableComment}")){
                line = line.replaceAll("\\$\\{tableComment}", tableComment);
            }

            //${entity} 实体类名称，例如：TbUser
            if(line.contains("${entity}")){
                line = line.replaceAll("\\$\\{entity}", replacement);
            }

            //${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser
            if(line.contains("${entityFirstToLowerCase}")){
                line = line.replaceAll("\\$\\{entityFirstToLowerCase}", StringUtil.camelCaseName(tableName));
            }

            //${entityToLowerCase} 实体类名称全小写，例如：tbuser
            if(line.contains("${entityToLowerCase}")){
                line = line.replaceAll("\\$\\{entityToLowerCase}", replacement.toLowerCase());
            }

            //${priDataType} 实体类主键类型，例如：String
            if(line.contains("${priDataType}")){
                line = line.replaceAll("\\$\\{priDataType}", StringUtil.typeMapping(prikey.getDataType()));
            }

            //处理自定义参数
            line = customParameter(line,customParameter);

            //先取得循环体的内容
            if(forFlag){
                forContent.append(line).append("\n");
            }

            //是否为for循环遍历表字段
            if(line.contains("#for")){
                forFlag = true;
            }
            if(line.contains("#end")){
                forFlag = false;
                line = line.replaceAll("#end", "");
            }

            //遍历循环体的内容，并设置值
            if(!forFlag && forContent.length() > 0){
                //遍历表字段
                for (TableInfo tableInfo : tableInfos) {
                    String tableColumns = forContent.toString()
                            //表字段信息：类型、名称、注释
                            .replaceAll("\\$\\{tableInfo.dataType}", StringUtil.typeMapping(tableInfo.getDataType()))
                            .replaceAll("\\$\\{tableInfo.columnName}", StringUtil.camelCaseName(tableInfo.getColumnName()))
                            .replaceAll("\\$\\{tableInfo.columnComment}", tableInfo.getColumnComment());

                    //清除多余#end，以及换行符
                    tableColumns = tableColumns.replaceAll("#end", "").replaceAll("\n", "");

                    //设置是否主键、是否自增
                    String pri = "",autoIncrement="";
                    //主键
                    if ("PRI".equals(tableInfo.getColumnKey())) {
                        pri = " @Id\n";
                        //自增id
                        if ("auto_increment".equals(tableInfo.getExtra())){
                            autoIncrement = "@GeneratedValue(strategy= GenerationType.IDENTITY)\n";
                        }
                    }
                    tableColumns = tableColumns
                            .replaceAll("#ifPri", pri)
                            .replaceAll("#ifAutoIncrement", autoIncrement);

                    //处理自定义参数
                    tableColumns = customParameter(tableColumns,customParameter);

                    //前补tab，后补换行符
                    stringBuffer.append("    ").append(tableColumns.trim()).append("\n\n");
                }
                //置空
                forContent.setLength(0);
            }

            if(!forFlag){
                stringBuffer.append(line).append("\n");
            }
        }

        //写入数据到到文件中
        FileUtil.fileWriter(file, stringBuffer);
    }catch (Exception e){
        e.printStackTrace();
    }
}

内置了几个重要参数

${tableName} 表名称，例如：tb_user
${tableComment} 表注释，例如：tb_user
${entity} 实体类名称，例如：TbUser
${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser
${entityToLowerCase} 实体类名称全小写，例如：tbuser
${priDataType} 实体类主键类型，例如：String

还有三个表字段信息：类型、名称、注释
${tableInfo.dataType}
${tableInfo.columnName}
${tableInfo.columnComment}

支持自定义参数Map customParameter，例如模板文件中的注释：

/**
 * ${author}
 * ${date}
 */

入口函数

/**
 * 快速创建，供外部调用，调用之前先设置一下项目的基础路径
 */
private String create() {
    System.out.println("生成路径位置：" + filePath);

    //获取表信息
    List tableInfo = getTableInfo();

    //驼峰标识映射后的表名
    String captureName = StringUtil.captureName(StringUtil.camelCaseName(tableName));

    //自定义参数
    HashMap customParameter = new HashMap<>();
    customParameter.put("author","作者：Auto Generator By 'huanzi-qch'");
    customParameter.put("date","生成日期："+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));

    //读取模板、生成代码
    writer(tlfPath+"controller.tlf",
            filePath + "controller\\" + captureName + "Controller.java",
            tableInfo,customParameter);
    writer(tlfPath+"entity.tlf",
            filePath + "pojo\\" + captureName + ".java",
            tableInfo,customParameter);
    writer(tlfPath+"entityvo.tlf",
            filePath + "vo\\" + captureName + "Vo.java",
            tableInfo,customParameter);
    writer(tlfPath+"repository.tlf",
            filePath + "repository\\" + captureName + "Repository.java",
            tableInfo,customParameter);
    writer(tlfPath+"service.tlf",
            filePath + "service\\" + captureName + "Service.java",
            tableInfo,customParameter);
    writer(tlfPath+"serviceimpl.tlf",
            filePath + "service\\" + captureName + "ServiceImpl.java",
            tableInfo,customParameter);

    return tableName + " 后台代码生成完毕！";
}

比较复杂的就是#for、#if的处理，我这里只是简单实现，不过也完全够我们用了

效果　　

V1.0版本

V2.0版本

后记

大部分项目的代码都是可以复用的，特别是像我们这种封装了一套通用代码，单表直接继承实现CRUD、分页等功能，每个模块高度相似的代码，代码生成器就成了敏捷开发中重要的一步，直接根据数据库表生成我们想要的代码，省去了一步步创建文件、复制粘贴文件内容的繁琐步骤，实现快速开发！

自己写的代码生成器，扩展性更强，满足每个业务模块的代码要求不成问题

开源

在这里贴出完整代码，全都在一个类里面，并且没有其他依赖包，很纯！

v1.0AutoGenerator

View Code

package cn.huanzi.qch.baseadmin.autogenerator;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

/**
 * 代码生成工具 V1.0
 */
public class AutoGenerator {

    /**
     * 程序自动设置
     */
    private String tableName;//表名
    private String tableComment;//表注释
    private String filePath;//最终文件生成位置

    /**
     * 数据连接相关，需要手动设置
     */
    private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";
    private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";

    /**
     * 基础路径，需要手动设置
     */
    private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置
    private String filePackage = basePackage + "sys\\";//文件所在包位置

    /**
     * 构造参数，设置表名
     */
    private AutoGenerator(String tableName) {
        //设置表名
        this.tableName = tableName;

        //文件所在包位置
        filePackage = filePackage + StringUtil.camelCaseName(tableName).toLowerCase() + "\\";

        //拼接完整最终位置 System.getProperty("user.dir") 获取的是项目所在路径，如果我们是子项目，则需要添加一层路径
        filePath = System.getProperty("user.dir") + "\\src\\main\\java\\" + filePackage;
    }

    /**
     * 创建pojo实体类
     */
    private void createPojo(List tableInfos) {
        //创建文件
        File file = FileUtil.createFile(filePath + "pojo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ".java");

        //拼接文件内容
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "pojo;\n" +
                        "\n" +
                        "import lombok.Data;\n" +
                        "import javax.persistence.*;\n" +
                        "import java.io.Serializable;\n" +
                        "import java.util.Date;\n" +
                        "\n" +
                        "@Entity\n" +
                        "@Table(name = \"" + tableName + "\")\n" +
                        "@Data\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + " implements Serializable {\n"
        );
        //遍历设置属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                stringBuffer.append("    @Id\n");
            }
            //自增
            if ("auto_increment".equals(tableInfo.getExtra())) {
                stringBuffer.append("    @GeneratedValue(strategy= GenerationType.IDENTITY)\n");
            }
            stringBuffer.append("    private ").append(StringUtil.typeMapping(tableInfo.getDataType())).append(" ").append(StringUtil.camelCaseName(tableInfo.getColumnName())).append(";//").append(tableInfo.getColumnComment()).append("\n\n");
        }
        stringBuffer.append("}");

        //写入文件内容
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建vo类
     */
    private void createVo(List tableInfos) {
        File file = FileUtil.createFile(filePath + "vo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo.java");
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "vo;\n" +
                        "\n" +
                        "import "+ basePackage.replaceAll("\\\\", ".") +" common.pojo.PageCondition;"+
                        "import lombok.Data;\n" +
                        "import java.io.Serializable;\n" +
                        "import java.util.Date;\n" +
                        "\n" +
                        "@Data\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo extends PageCondition implements Serializable {\n"
        );
        //遍历设置属性
        for (TableInfo tableInfo : tableInfos) {
            stringBuffer.append("    private ").append(StringUtil.typeMapping(tableInfo.getDataType())).append(" ").append(StringUtil.camelCaseName(tableInfo.getColumnName())).append(";//").append(tableInfo.getColumnComment()).append("\n\n");
        }
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建repository类
     */
    private void createRepository(List tableInfos) {
        File file = FileUtil.createFile(filePath + "repository\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "repository;\n" +
                        "\n" +
                        "import " + basePackage.replaceAll("\\\\", ".") + "common.repository.*;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import org.springframework.stereotype.Repository;\n" +
                        "\n" +
                        "@Repository\n" +
                        "public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository extends CommonRepository<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建service类
     */
    private void createService(List tableInfos) {
        File file = FileUtil.createFile(filePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "service;\n" +
                        "\n" +
                        "import " + basePackage.replaceAll("\\\\", ".") + "common.service.*;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "\n" +
                        "public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service extends CommonService<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);

        //Impl
        File file1 = FileUtil.createFile(filePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl.java");
        StringBuffer stringBuffer1 = new StringBuffer();
        stringBuffer1.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "service;\n" +
                        "\n" +
                        "import " + basePackage.replaceAll("\\\\", ".") + "common.service.*;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "repository." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository;\n" +
                        "import org.springframework.beans.factory.annotation.Autowired;\n" +
                        "import org.springframework.stereotype.Service;\n" +
                        "import org.springframework.transaction.annotation.Transactional;\n" +
                        "import javax.persistence.EntityManager;\n" +
                        "import javax.persistence.PersistenceContext;\n" +
                        "\n" +
                        "@Service\n" +
                        "@Transactional\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl extends CommonServiceImpl<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> implements " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service{"
        );
        stringBuffer1.append("\n\n");
        stringBuffer1.append(
                "    @PersistenceContext\n" +
                        "    private EntityManager em;\n");

        stringBuffer1.append("" +
                "    @Autowired\n" +
                "    private " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository " + StringUtil.camelCaseName(tableName) + "Repository;\n");
        stringBuffer1.append("}");
        FileUtil.fileWriter(file1, stringBuffer1);
    }

    /**
     * 创建controller类
     */
    private void createController(List tableInfos) {
        File file = FileUtil.createFile(filePath + "controller\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + filePackage.replaceAll("\\\\", ".") + "controller;\n" +
                        "\n" +
                        "import " + basePackage.replaceAll("\\\\", ".") + "common.controller.*;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "import " + filePackage.replaceAll("\\\\", ".") + "service." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service;\n" +
                        "import org.springframework.beans.factory.annotation.Autowired;\n" +
                        "import org.springframework.web.bind.annotation.*;\n" +
                        "\n" +
                        "@RestController\n" +
                        "@RequestMapping(\"/sys/" + StringUtil.camelCaseName(tableName) + "/\")\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller extends CommonController<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("" +
                "    @Autowired\n" +
                "    private " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service " + StringUtil.camelCaseName(tableName) + "Service;\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * file工具类
     */
    private static class FileUtil {
        /**
         * 创建文件
         *
         * @param pathNameAndFileName 路径跟文件名
         * @return File对象
         */
        private static File createFile(String pathNameAndFileName) {
            File file = new File(pathNameAndFileName);
            try {
                //获取父目录
                File fileParent = file.getParentFile();
                if (!fileParent.exists()) {
                    fileParent.mkdirs();
                }
                //创建文件
                if (!file.exists()) {
                    file.createNewFile();
                }
            } catch (Exception e) {
                file = null;
                System.err.println("新建文件操作出错");
                e.printStackTrace();
            }
            return file;
        }

        /**
         * 字符流写入文件
         *
         * @param file         file对象
         * @param stringBuffer 要写入的数据
         */
        private static void fileWriter(File file, StringBuffer stringBuffer) {
            //字符流
            try {
                FileWriter resultFile = new FileWriter(file, false);//true,则追加写入 false,则覆盖写入
                PrintWriter myFile = new PrintWriter(resultFile);
                //写入
                myFile.println(stringBuffer.toString());

                myFile.close();
                resultFile.close();
            } catch (Exception e) {
                System.err.println("写入操作出错");
                e.printStackTrace();
            }
        }
    }

    /**
     * 字符串处理工具类
     */
    private static class StringUtil {
        /**
         * 数据库类型->JAVA类型
         *
         * @param dbType 数据库类型
         * @return JAVA类型
         */
        private static String typeMapping(String dbType) {
            String javaType;
            if ("int|integer".contains(dbType)) {
                javaType = "Integer";
            } else if ("float|double|decimal|real".contains(dbType)) {
                javaType = "Double";
            } else if ("date|time|datetime|timestamp".contains(dbType)) {
                javaType = "Date";
            } else {
                javaType = "String";
            }
            return javaType;
        }

        /**
         * 驼峰转换为下划线
         */
        private static String underscoreName(String camelCaseName) {
            StringBuilder result = new StringBuilder();
            if (camelCaseName != null && camelCaseName.length() > 0) {
                result.append(camelCaseName.substring(0, 1).toLowerCase());
                for (int i = 1; i < camelCaseName.length(); i++) {
                    char ch = camelCaseName.charAt(i);
                    if (Character.isUpperCase(ch)) {
                        result.append("_");
                        result.append(Character.toLowerCase(ch));
                    } else {
                        result.append(ch);
                    }
                }
            }
            return result.toString();
        }

        /**
         * 首字母大写
         */
        private static String captureName(String name) {
            char[] cs = name.toCharArray();
            cs[0] -= 32;
            return String.valueOf(cs);

        }

        /**
         * 下划线转换为驼峰
         */
        private static String camelCaseName(String underscoreName) {
            StringBuilder result = new StringBuilder();
            if (underscoreName != null && underscoreName.length() > 0) {
                boolean flag = false;
                for (int i = 0; i < underscoreName.length(); i++) {
                    char ch = underscoreName.charAt(i);
                    if ("_".charAt(0) == ch) {
                        flag = true;
                    } else {
                        if (flag) {
                            result.append(Character.toUpperCase(ch));
                            flag = false;
                        } else {
                            result.append(ch);
                        }
                    }
                }
            }
            return result.toString();
        }
    }

    /**
     * JDBC连接数据库工具类
     */
    private static class DBConnectionUtil {

        static {
            // 1、加载驱动
            try {
                Class.forName(DRIVER_CLASSNAME);
            } catch (ClassNotFoundException e) {
                
                e.printStackTrace();
            }
        }

        /**
         * 返回一个Connection连接
         */
        static Connection getConnection() {
            Connection conn = null;
            // 2、连接数据库
            try {
                conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            } catch (SQLException e) {
                
                e.printStackTrace();
            }
            return conn;
        }

        /**
         * 关闭Connection，Statement连接
         */
        public static void close(Connection conn, Statement stmt) {
            try {
                conn.close();
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        /**
         * 关闭Connection，Statement，ResultSet连接
         */
        public static void close(Connection conn, Statement stmt, ResultSet rs) {
            try {
                close(conn, stmt);
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

    /**
     * 表结构信息实体类
     */
    private class TableInfo {
        private String columnName;//字段名
        private String dataType;//字段类型
        private String columnComment;//字段注释
        private String columnKey;//主键
        private String extra;//主键类型

        public String getColumnName() {
            return columnName;
        }

        public void setColumnName(String columnName) {
            this.columnName = columnName;
        }

        public String getDataType() {
            return dataType;
        }

        public void setDataType(String dataType) {
            this.dataType = dataType;
        }

        public String getColumnComment() {
            return columnComment;
        }

        public void setColumnComment(String columnComment) {
            this.columnComment = columnComment;
        }

        public String getColumnKey() {
            return columnKey;
        }

        public void setColumnKey(String columnKey) {
            this.columnKey = columnKey;
        }

        public String getExtra() {
            return extra;
        }

        public void setExtra(String extra) {
            this.extra = extra;
        }
    }

    /**
     * 获取表结构信息
     * 目前仅支持mysql
     */
    private List getTableInfo() {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        ArrayList list = new ArrayList<>();
        try {
            conn = DBConnectionUtil.getConnection();

            //表字段信息
            String sql = "select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_schema = (select database()) and table_name=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, tableName);
            rs = ps.executeQuery();
            while (rs.next()) {
                TableInfo tableInfo = new TableInfo();
                //列名，全部转为小写
                tableInfo.setColumnName(rs.getString("column_name").toLowerCase());
                //列类型
                tableInfo.setDataType(rs.getString("data_type"));
                //列注释
                tableInfo.setColumnComment(rs.getString("column_comment"));
                //主键
                tableInfo.setColumnKey(rs.getString("column_key"));
                //主键类型
                tableInfo.setExtra(rs.getString("extra"));
                list.add(tableInfo);
            }

            //表注释
            sql = "select table_comment from information_schema.tables where table_schema = (select database()) and table_name=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, tableName);
            rs = ps.executeQuery();
            while (rs.next()) {
                //表注释
                tableComment = rs.getString("table_comment");
            }
        } catch (SQLException e) {

            e.printStackTrace();
        } finally {
            if(rs != null){
                DBConnectionUtil.close(conn, ps, rs);
            }
        }
        return list;
    }

    /**
     * 快速创建，供外部调用，调用之前先设置一下项目的基础路径
     */
    private String create() {
        System.out.println("生成路径位置：" + filePath);

        //获取表信息
        List tableInfo = getTableInfo();

        //开始生成代码
        createPojo(tableInfo);
        createVo(tableInfo);
        createRepository(tableInfo);
        createService(tableInfo);
        createController(tableInfo);

        return tableName + " 后台代码生成完毕！";
    }

    public static void main(String[] args) {
//        String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};
        String[] tables = {"tb_user"};
        for (String table : tables) {
            String msg = new AutoGenerator(table).create();
            System.out.println(msg);
        }
    }
}

v2.0  AutoGeneratorPlus

View Code

package cn.huanzi.qch.baseadmin.autogenerator;

import java.io.*;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 代码生成工具 V2.0
 */
public class AutoGeneratorPlus {

    /**
     * 程序自动设置
     */
    private String tableName;//表名
    private String tableComment;//表注释
    private String filePath;//最终文件生成位置

    /**
     * 数据连接相关，需要手动设置
     */
    private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";
    private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";

    /**
     * 基础路径，需要手动设置
     */
    private String tlfPath = System.getProperty("user.dir") + "\\src\\main\\resources\\tlf\\";//模板文件位置
    private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置
    private String filePackage = basePackage + "sys\\";//文件所在包位置

    /**
     * 构造参数，设置表名
     */
    private AutoGeneratorPlus(String tableName) {
        //设置表名
        this.tableName = tableName;

        //文件所在包位置
        filePackage = filePackage + StringUtil.camelCaseName(tableName).toLowerCase() + "\\";

        //拼接完整最终位置 System.getProperty("user.dir") 获取的是项目所在路径，如果我们是子项目，则需要添加一层路径
        filePath = System.getProperty("user.dir") + "\\src\\main\\java\\" + filePackage;
    }

    /**
     * 读取模板，设置内容，生成文件
     * @param templatePath 模板文件路径
     * @param outputFile 文件生成路径
     * @param tableInfos 表字段信息
     * @param customParameter 自定义参数
     */
    private void writer(String templatePath, String outputFile,List tableInfos,Map customParameter){
        //主键
        TableInfo prikey = new TableInfo();

        //for循环标识
        boolean forFlag = false;
        StringBuilder forContent = new StringBuilder();

        //驼峰标识映射后的表名
        String replacement = StringUtil.captureName(StringUtil.camelCaseName(tableName));

        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                prikey = tableInfo;
                break;
            }
        }

        try(FileReader fileReader = new FileReader(templatePath);
            BufferedReader reader = new BufferedReader(fileReader)) {
            //生成文件
            File file = FileUtil.createFile(outputFile);
            StringBuffer stringBuffer = new StringBuffer();

            //读取模板文件，拼接文件内容
            Object[] lines = reader.lines().toArray();
            for (Object o : lines) {
                String line = String.valueOf(o);

                /* 设置值 */

                //${tableName} 表名称，例如：tb_user
                if(line.contains("${tableName}")){
                    line = line.replaceAll("\\$\\{tableName}", tableName);
                }

                //${tableComment} 表注释，例如：tb_user
                if(line.contains("${tableComment}")){
                    line = line.replaceAll("\\$\\{tableComment}", tableComment);
                }

                //${entity} 实体类名称，例如：TbUser
                if(line.contains("${entity}")){
                    line = line.replaceAll("\\$\\{entity}", replacement);
                }

                //${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser
                if(line.contains("${entityFirstToLowerCase}")){
                    line = line.replaceAll("\\$\\{entityFirstToLowerCase}", StringUtil.camelCaseName(tableName));
                }

                //${entityToLowerCase} 实体类名称全小写，例如：tbuser
                if(line.contains("${entityToLowerCase}")){
                    line = line.replaceAll("\\$\\{entityToLowerCase}", replacement.toLowerCase());
                }

                //${priDataType} 实体类主键类型，例如：String
                if(line.contains("${priDataType}")){
                    line = line.replaceAll("\\$\\{priDataType}", StringUtil.typeMapping(prikey.getDataType()));
                }

                //处理自定义参数
                line = customParameter(line,customParameter);

                //先取得循环体的内容
                if(forFlag){
                    forContent.append(line).append("\n");
                }

                //是否为for循环遍历表字段
                if(line.contains("#for")){
                    forFlag = true;
                }
                if(line.contains("#end")){
                    forFlag = false;
                    line = line.replaceAll("#end", "");
                }

                //遍历循环体的内容，并设置值
                if(!forFlag && forContent.length() > 0){
                    //遍历表字段
                    for (TableInfo tableInfo : tableInfos) {
                        String tableColumns = forContent.toString()
                                //表字段信息：类型、名称、注释
                                .replaceAll("\\$\\{tableInfo.dataType}", StringUtil.typeMapping(tableInfo.getDataType()))
                                .replaceAll("\\$\\{tableInfo.columnName}", StringUtil.camelCaseName(tableInfo.getColumnName()))
                                .replaceAll("\\$\\{tableInfo.columnComment}", tableInfo.getColumnComment());

                        //清除多余#end，以及换行符
                        tableColumns = tableColumns.replaceAll("#end", "").replaceAll("\n", "");

                        //设置是否主键、是否自增
                        String pri = "",autoIncrement="";
                        //主键
                        if ("PRI".equals(tableInfo.getColumnKey())) {
                            pri = " @Id\n";
                            //自增id
                            if ("auto_increment".equals(tableInfo.getExtra())){
                                autoIncrement = "@GeneratedValue(strategy= GenerationType.IDENTITY)\n";
                            }
                        }
                        tableColumns = tableColumns
                                .replaceAll("#ifPri", pri)
                                .replaceAll("#ifAutoIncrement", autoIncrement);

                        //处理自定义参数
                        tableColumns = customParameter(tableColumns,customParameter);

                        //前补tab，后补换行符
                        stringBuffer.append("    ").append(tableColumns.trim()).append("\n\n");
                    }
                    //置空
                    forContent.setLength(0);
                }

                if(!forFlag){
                    stringBuffer.append(line).append("\n");
                }
            }

            //写入数据到到文件中
            FileUtil.fileWriter(file, stringBuffer);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    private void writer(String templatePath, String outputFile,List tableInfos){
        writer(templatePath,outputFile,tableInfos,new HashMap<>());
    }

    /**
     * 处理自定义参数
     */
    private String customParameter(String str,Map customParameter){
        for (String key : customParameter.keySet()) {
            str = str.replaceAll("\\$\\{"+key+"}",customParameter.get(key));
        }
        return str;
    }

    /**
     * file工具类
     */
    private static class FileUtil {
        /**
         * 创建文件
         *
         * @param pathNameAndFileName 路径跟文件名
         * @return File对象
         */
        private static File createFile(String pathNameAndFileName) {
            File file = new File(pathNameAndFileName);
            try {
                //获取父目录
                File fileParent = file.getParentFile();
                if (!fileParent.exists()) {
                    fileParent.mkdirs();
                }
                //创建文件
                if (!file.exists()) {
                    file.createNewFile();
                }
            } catch (Exception e) {
                file = null;
                System.err.println("新建文件操作出错");
                e.printStackTrace();
            }
            return file;
        }

        /**
         * 字符流写入文件
         *
         * @param file         file对象
         * @param stringBuffer 要写入的数据
         */
        private static void fileWriter(File file, StringBuffer stringBuffer) {
            //字符流
            try {
                FileWriter resultFile = new FileWriter(file, false);//true,则追加写入 false,则覆盖写入
                PrintWriter myFile = new PrintWriter(resultFile);
                //写入
                myFile.println(stringBuffer.toString());

                myFile.close();
                resultFile.close();
            } catch (Exception e) {
                System.err.println("写入操作出错");
                e.printStackTrace();
            }
        }
    }

    /**
     * 字符串处理工具类
     */
    private static class StringUtil {
        /**
         * 数据库类型->JAVA类型
         *
         * @param dbType 数据库类型
         * @return JAVA类型
         */
        private static String typeMapping(String dbType) {
            String javaType;
            if ("int|integer".contains(dbType)) {
                javaType = "Integer";
            } else if ("float|double|decimal|real".contains(dbType)) {
                javaType = "Double";
            } else if ("date|time|datetime|timestamp".contains(dbType)) {
                javaType = "Date";
            } else {
                javaType = "String";
            }
            return javaType;
        }

        /**
         * 驼峰转换为下划线
         */
        private static String underscoreName(String camelCaseName) {
            StringBuilder result = new StringBuilder();
            if (camelCaseName != null && camelCaseName.length() > 0) {
                result.append(camelCaseName.substring(0, 1).toLowerCase());
                for (int i = 1; i < camelCaseName.length(); i++) {
                    char ch = camelCaseName.charAt(i);
                    if (Character.isUpperCase(ch)) {
                        result.append("_");
                        result.append(Character.toLowerCase(ch));
                    } else {
                        result.append(ch);
                    }
                }
            }
            return result.toString();
        }

        /**
         * 首字母大写
         */
        private static String captureName(String name) {
            char[] cs = name.toCharArray();
            cs[0] -= 32;
            return String.valueOf(cs);

        }

        /**
         * 下划线转换为驼峰
         */
        private static String camelCaseName(String underscoreName) {
            StringBuilder result = new StringBuilder();
            if (underscoreName != null && underscoreName.length() > 0) {
                boolean flag = false;
                for (int i = 0; i < underscoreName.length(); i++) {
                    char ch = underscoreName.charAt(i);
                    if ("_".charAt(0) == ch) {
                        flag = true;
                    } else {
                        if (flag) {
                            result.append(Character.toUpperCase(ch));
                            flag = false;
                        } else {
                            result.append(ch);
                        }
                    }
                }
            }
            return result.toString();
        }
    }

    /**
     * JDBC连接数据库工具类
     */
    private static class DBConnectionUtil {

        static {
            // 1、加载驱动
            try {
                Class.forName(DRIVER_CLASSNAME);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        }

        /**
         * 返回一个Connection连接
         */
        static Connection getConnection() {
            Connection conn = null;
            // 2、连接数据库
            try {
                conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return conn;
        }

        /**
         * 关闭Connection，Statement连接
         */
        public static void close(Connection conn, Statement stmt) {
            try {
                conn.close();
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        /**
         * 关闭Connection，Statement，ResultSet连接
         */
        public static void close(Connection conn, Statement stmt, ResultSet rs) {
            try {
                close(conn, stmt);
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

    /**
     * 表结构信息实体类
     */
    private class TableInfo {
        private String columnName;//字段名
        private String dataType;//字段类型
        private String columnComment;//字段注释
        private String columnKey;//主键
        private String extra;//主键类型

        public String getColumnName() {
            return columnName;
        }

        public void setColumnName(String columnName) {
            this.columnName = columnName;
        }

        public String getDataType() {
            return dataType;
        }

        public void setDataType(String dataType) {
            this.dataType = dataType;
        }

        public String getColumnComment() {
            return columnComment;
        }

        public void setColumnComment(String columnComment) {
            this.columnComment = columnComment;
        }

        public String getColumnKey() {
            return columnKey;
        }

        public void setColumnKey(String columnKey) {
            this.columnKey = columnKey;
        }

        public String getExtra() {
            return extra;
        }

        public void setExtra(String extra) {
            this.extra = extra;
        }
    }

    /**
     * 获取表结构信息
     * 目前仅支持mysql
     */
    private List getTableInfo() {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        ArrayList list = new ArrayList<>();
        try {
            conn = DBConnectionUtil.getConnection();

            //表字段信息
            String sql = "select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_schema = (select database()) and table_name=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, tableName);
            rs = ps.executeQuery();
            while (rs.next()) {
                TableInfo tableInfo = new TableInfo();
                //列名，全部转为小写
                tableInfo.setColumnName(rs.getString("column_name").toLowerCase());
                //列类型
                tableInfo.setDataType(rs.getString("data_type"));
                //列注释
                tableInfo.setColumnComment(rs.getString("column_comment"));
                //主键
                tableInfo.setColumnKey(rs.getString("column_key"));
                //主键类型
                tableInfo.setExtra(rs.getString("extra"));
                list.add(tableInfo);
            }

            //表注释
            sql = "select table_comment from information_schema.tables where table_schema = (select database()) and table_name=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, tableName);
            rs = ps.executeQuery();
            while (rs.next()) {
                //表注释
                tableComment = rs.getString("table_comment");
            }
        } catch (SQLException e) {

            e.printStackTrace();
        } finally {
            if(rs != null){
                DBConnectionUtil.close(conn, ps, rs);
            }
        }
        return list;
    }

    /**
     * 快速创建，供外部调用，调用之前先设置一下项目的基础路径
     */
    private String create() {
        System.out.println("生成路径位置：" + filePath);

        //获取表信息
        List tableInfo = getTableInfo();

        //驼峰标识映射后的表名
        String captureName = StringUtil.captureName(StringUtil.camelCaseName(tableName));

        //自定义参数
        HashMap customParameter = new HashMap<>();
        customParameter.put("author","作者：Auto Generator By 'huanzi-qch'");
        customParameter.put("date","生成日期："+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));

        //读取模板、生成代码
        writer(tlfPath+"controller.tlf",
                filePath + "controller\\" + captureName + "Controller.java",
                tableInfo,customParameter);
        writer(tlfPath+"entity.tlf",
                filePath + "pojo\\" + captureName + ".java",
                tableInfo,customParameter);
        writer(tlfPath+"entityvo.tlf",
                filePath + "vo\\" + captureName + "Vo.java",
                tableInfo,customParameter);
        writer(tlfPath+"repository.tlf",
                filePath + "repository\\" + captureName + "Repository.java",
                tableInfo,customParameter);
        writer(tlfPath+"service.tlf",
                filePath + "service\\" + captureName + "Service.java",
                tableInfo,customParameter);
        writer(tlfPath+"serviceimpl.tlf",
                filePath + "service\\" + captureName + "ServiceImpl.java",
                tableInfo,customParameter);

        return tableName + " 后台代码生成完毕！";
    }

    public static void main(String[] args) {
//        String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};
        String[] tables = {"tb_user"};
        for (String table : tables) {
            String msg = new AutoGeneratorPlus(table).create();
            System.out.println(msg);
        }
    }
}

同时，所有代码都在base admin项目里，代码已经开源、托管到我的GitHub、码云：

GitHub：https://github.com/huanzi-qch/base-admin

码云：https://gitee.com/huanzi-qch/base-admin

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