MybatisPlus搭建项目

一、搭建项目环境

1.1 创建项目

1.2 配置环境

导入分页依赖

 <!--用于生存代码-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.31</version>
        </dependency>

修改MySQL的版本

1.1.1 自动生成代码

首先在resources下创建项目mappers

修改application.yml

server:
    port: 8080
spring:
    application:
        name: springbootxm
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        name: defaultDataSource
        password: 123456
        url: jdbc:mysql://localhost:3306/y101?useUnicode=true&characterEncoding=UTF-8
        username: root
    freemarker:
        cache: false
        charset: utf-8
        expose-request-attributes: true
        expose-session-attributes: true
        suffix: .ftl
        template-loader-path: classpath:/templates/
#    resources:
#        static-locations: classpath:/static/# 应用服务 WEB 访问端口
    mvc:
        static-path-pattern: /static/**
#打印SQL语句
logging:
    level:
        com.xlb.springbootassets: debug
#配置映射
mybatis-plus:
    mapper-locations: classpath:mappers/**/*.xml
    type-aliases-package: com.xlb.springbootxm.bj.model

引入生成代码类

MPGenerator

package com.xlb.springbootxm.mp;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.*;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * mybatis-plus代码生成
 */
public class MPGenerator {

    /**
     * 

     * 读取控制台内容
     * 
     */
    public static String scanner(String tip) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder help = new StringBuilder();
        help.append("请输入" + tip);
        System.out.println(help.toString());
        if (scanner.hasNext()) {
            String ipt = scanner.next();
            if (StringUtils.isNotBlank(ipt)) {
                if ("quit".equals(ipt)) return "";
                return ipt;
            }
        }
        throw new MybatisPlusException("请输入正确的" + tip + "！");
    }

    public static void main(String[] args) {
        // 代码生成器
        AutoGenerator mpg = new AutoGenerator();

        // 1.全局配置
        GlobalConfig gc = new GlobalConfig();
        //System.getProperty("user.dir")指工作区间 如我们工作期间名是iderr
        String projectPath = System.getProperty("user.dir") + "/springbootxm";
        System.out.println(projectPath);

        gc.setOutputDir(projectPath + "/src/main/java");
        gc.setOpen(false);
        gc.setBaseResultMap(true);//生成BaseResultMap
        gc.setActiveRecord(false);// 不需要ActiveRecord特性的请改为false
        gc.setEnableCache(false);// XML 二级缓存
        gc.setBaseResultMap(true);// XML ResultMap
        gc.setBaseColumnList(true);// XML columList
        //gc.setSwagger2(true); //实体属性 Swagger2 注解
        gc.setAuthor("小谢");

        // 自定义文件命名，注意 %s 会自动填充表实体属性！
        gc.setMapperName("%sMapper");
        gc.setXmlName("%sMapper");
        gc.setServiceName("%sService");
        gc.setServiceImplName("%sServiceImpl");
        gc.setControllerName("%sController");

        gc.setIdType(IdType.AUTO);
        mpg.setGlobalConfig(gc);

        // 2.数据源配置
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setDbType(DbType.MYSQL);
        dsc.setUrl("jdbc:mysql://localhost:3306/y101?useUnicode=true&characterEncoding=UTF-8");
        dsc.setDriverName("com.mysql.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("123456");
        mpg.setDataSource(dsc);

        // 3.包配置
        PackageConfig pc = new PackageConfig();
        String moduleName = scanner("模块名(quit退出，表示没有模块名)");
        if (StringUtils.isNotBlank(moduleName)) {
            pc.setModuleName(moduleName);
        }

        //设置父包
        pc.setParent("com.xlb.springbootxm")
                .setMapper("mapper")
                .setService("service")
                .setController("controller")
                .setEntity("model");
        mpg.setPackageInfo(pc);

        // 4.自定义配置
        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap() {
                // to do nothing
            }
        };

        // 如果模板引擎是 freemarker
        String templatePath = "/templates/mapper.xml.ftl";
        // 自定义输出配置
        List<FileOutConfig> focList = new ArrayList<>();
        // 自定义配置会被优先输出
        focList.add(new FileOutConfig(templatePath) {
            @Override
            public String outputFile(TableInfo tableInfo) {
                // 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！
                if (StringUtils.isNotBlank(pc.getModuleName())) {
                    return projectPath + "/src/main/resources/mappers/" + pc.getModuleName() + "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
                } else {
                    return projectPath + "/src/main/resources/mappers/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
                }
            }
        });
        cfg.setFileOutConfigList(focList);
        mpg.setCfg(cfg);
        // 配置模板
        TemplateConfig templateConfig = new TemplateConfig();
        templateConfig.setXml(null);
        mpg.setTemplate(templateConfig);

        // 5.策略配置
        StrategyConfig strategy = new StrategyConfig();
        // 表名生成策略(下划线转驼峰命名)
        strategy.setNaming(NamingStrategy.underline_to_camel);
        // 列名生成策略(下划线转驼峰命名)
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);
        // 是否启动Lombok配置
        strategy.setEntityLombokModel(true);
        // 是否启动REST风格配置
        strategy.setRestControllerStyle(true);
        // 自定义实体父类strategy.setSuperEntityClass("com.baomidou.mybatisplus.extension.activerecord.Model");
        // 自定义service父接口strategy.setSuperServiceClass("com.baomidou.mybatisplus.extension.service.IService");
        // 自定义service实现类strategy.setSuperServiceImplClass("com.baomidou.mybatisplus.extension.service.impl.ServiceImpl");
        // 自定义mapper接口strategy.setSuperMapperClass("com.baomidou.mybatisplus.core.mapper.BaseMapper");
        strategy.setSuperEntityColumns("id");

        // 写于父类中的公共字段plus
        strategy.setSuperEntityColumns("id");
        strategy.setInclude(scanner("表名，多个英文逗号分割").split(","));
        strategy.setControllerMappingHyphenStyle(true);

        //表名前缀(可变参数)：“t_”或”“t_模块名”，例如：t_user或t_sys_user
        strategy.setTablePrefix("t_", "t_sys_");
        //strategy.setTablePrefix(scanner("请输入表前缀"));
        mpg.setStrategy(strategy);
        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        // 执行
        mpg.execute();
    }
}

运行生成代码

1.1.2 配置SpringbootassetsApplication

SpringbootassetsApplication

package com.xlb.springbootxm;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.EnableTransactionManagement;


//完成对mapper接口的扫描
@MapperScan("com.xlb.springbootxm.bj.mapper")
//开启事务管理
@EnableTransactionManagement
@SpringBootApplication
public class SpringbootxmApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootxmApplication.class, args);
    }

}

1.3 配置application.yml

server:
    port: 8080
spring:
    application:
        name: springbootxm
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        name: defaultDataSource
        password: 123456
        url: jdbc:mysql://localhost:3306/y101?useUnicode=true&characterEncoding=UTF-8
        username: root
    freemarker:
        cache: false
        charset: utf-8
        expose-request-attributes: true
        expose-session-attributes: true
        suffix: .ftl
#        template-loader-path: classpath:/templates/
#    resources:
#        static-locations: classpath:/static/# 应用服务 WEB 访问端口
    mvc:
        static-path-pattern: /static/**
#打印SQL语句
logging:
    level:
        com.xlb.springbootassets: debug
#配置映射
mybatis-plus:
    mapper-locations: classpath:mappers/**/*.xml
    type-aliases-package: com.xlb.springbootxm.bj.model

1.4 编写controller层

因为自动生成代码注解是==@RestController==，等价于@Controller + @ResponseBody。但是@ResponseBody表示方法的返回值直接以指定的格式写入Http response body中，而不是解析为跳转路径。所以我们要把注解改为==@Controller==

StrutsClassController

package com.xlb.springbootmp.book.controller;


import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.xlb.springbootmp.book.model.MvcBook;
import com.xlb.springbootmp.book.service.MvcBookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 

 *  前端控制器
 * 
 *
 * @author lky
 * @since 2022-11-01
 */
@Controller
@RequestMapping("/book")
public class MvcBookController {
    @Autowired
    private MvcBookService mvcBookService;

    //查询单个
    @GetMapping("/list")
    public List<MvcBook> list(){
        return mvcBookService.list();
    }

    //按条件查询
    @GetMapping("/listByCondition")
    public List<MvcBook> listByCondition(MvcBook mvcBook){
        QueryWrapper qw = new QueryWrapper();
        //key代表数据库自段  value代表查询的值 like代表模糊查询
        qw.like("bname", mvcBook.getBname());
        return mvcBookService.list(qw);
    }

    //查询单个
    @GetMapping("/get")
    public MvcBook get(MvcBook mvcBook){
        return mvcBookService.getById(mvcBook.getBid());
    }


    //增加
    @PutMapping("/add")
    public boolean add(MvcBook mvcBook){
        boolean save = mvcBookService.save(mvcBook);
        return save;
    }


    //删除
    @DeleteMapping("/del")
    public boolean del(MvcBook mvcBook){
        return mvcBookService.removeById(mvcBook.getBid());
    }

    //修改
    @PostMapping("/edit")
    public boolean edit(MvcBook mvcBook){
        return mvcBookService.saveOrUpdate(mvcBook);
    }

    // 连表查询
    @GetMapping("/userRole")
    public List<Map> userRole(String uname){
        Map map = new HashMap();
        map.put("username",uname);
        List<Map> maps = mvcBookService.queryUserRole(map);
        return maps;
    }

}

1.5 编写前台代码

目录

headd.ftl

<#--局部变量-->
<#assign ctx>
    ${springMacroRequestContext.contextPath}
</#assign>


<#--全局变量-->
<#global ctx2>
    ${springMacroRequestContext.contextPath}
</#global>

clzEdit.ftl

<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>博客的编辑界面</title>
</head>
<body>
<#include '/headd.ftl' />
<#if b??>
   <#-- 修改-->
    <form action="${ctx }/clz/edit">
       
        cname:<input type="text" name="cname" value="${b.cname !}">
        cteacher:<input type="text" name="cteacher" value="${b.cteacher !}">
        pic:<input type="text" name="pic" value="${b.pic !}">
        <input type="submit">
    </form>
    <#else>
        <#-- 新增 -->
        <form action="${ctx }/clz/add" method="post">
            
            cname:<input type="text" name="cname" value="">
            cteacher:<input type="text" name="cteacher" value="">
            pic:<input type="text" name="pic" value="">
            <input type="submit">
        </form>
    </#if>

</body>
</html>

clzList.ftl

<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <link
            href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
            rel="stylesheet">
    <script
            src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
    <title>博客列表</title>
    <style type="text/css">
        .page-item input {
            padding: 0;
            width: 40px;
            height: 100%;
            text-align: center;
            margin: 0 6px;
        }

        .page-item input, .page-item b {
            line-height: 38px;
            float: left;
            font-weight: 400;
        }

        .page-item.go-input {
            margin: 0 10px;
        }
    </style>
</head>
<body>
<#include '/headd.ftl' />
<#-- 查询条件框  -->
<form class="form-inline"
      action="${ctx}/clz/list" method="post">
    <div class="form-group mb-2">
        <input type="text" class="form-control-plaintext" name="cname"
               placeholder="请输入班级名称">
    </div>
    <button type="submit" class="btn btn-primary mb-2">查询</button>
    <a class="btn btn-primary mb-2" href="${ctx}/clz/toEdit">新增</a>
</form>
<table class="table table-striped bg-success">
    <thead>
    <tr>
        <th scope="col">ID</th>
        <th scope="col">班级名称</th>
        <th scope="col">指导老师</th>
        <th scope="col">班级相册</th>
        <th scope="col">操作</th>
    </tr>
    </thead>
    <tbody>
    <#list lst as b>
        <tr>
            <td>${b.cid !}</td>
            <td>${b.cname !}</td>
            <td>${b.cteacher !}</td>
            <td>${b.pic !}</td>
            <td>
                <a href="${ctx }/clz/toEdit?cid=${b.cid}">修改</a>
                <a href="${ctx }/clz/del?cid=${b.cid}">删除</a>
            </td>
        </tr>
    </#list>
    </tbody>
</table>
</body>
</html>

1.6 测试

1.6.1 查询

1.6.2 新增

1.6.3 修改

1.6.4 删除

二、MyBatis-Plus分页插件

2.1 创建插件配置类

MybatisPlusConfig

package com.xlb.springbootassets.bj.config;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {

    /**
     * 分页插件配置
     *
     * @return
     */
    //从MyBatis-Plus 3.4.0开始，不再使用旧版本的PaginationInterceptor ，而是使用MybatisPlusInterceptor。
    //使用分页插件需要配置MybatisPlusInterceptor，将分页拦截器添加进来：
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        // 向MyBatis-Plus的过滤器链中添加分页拦截器，需要设置数据库类型（主要用于分页方言）
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

2.2 编写SQL

StrutsClassMapper.xml

<select id="selectPageVo" resultType="com.xlb.springbootassets.bj.model.StrutsClass">
        select cid,cname,cteacher,pic FROM t_struts_class WHERE cname=#{cname}
    </select>

2.3 mapper层

//亲测这里最前面使用Ipage和Page是一样的，如果这里使用的是Page，下面也要改。但是还是推荐官网上面的Ipage，不改最好。
    IPage<StrutsClass> selectPageVo(Page<StrutsClass> page,String clazz);

2.4 service层

StrutsClassService

//分页方法
    IPage<StrutsClass> selectPageVo(Page<StrutsClass> page,String clazz);

StrutsClassServiceImpl

@Override
    public IPage<StrutsClass> selectPageVo(Page<StrutsClass> page,String clazz) {
        return strutsClassMapper.selectPageVo(page,clazz);
    }

2.5 controller 层

//分页方法
    @RequestMapping("/pagelist")
    public IPage<StrutsClass> pagelist(@RequestBody String clazz){
        Page<StrutsClass> page1 = new Page<>();
        Page<StrutsClass> page = new Page<>(1,10);
        return strutsClassService.selectPageVo(page,clazz);
    }