【Mybatis】逆向工程简单demo

1. 是什么

Mybatis逆向工程，可以通过配置数据库信息，配置对应参数，由数据库表生成对应的Mapper接口跟mapper.xml文件，以及实体类Bean，方便我们进行开发，让我们不用再去写mapper.xml配置文件。

2. 怎么用

1. 创建maven工程：
   

2. 配置Maven,在pom.xml中配置mybatis，跟mysql相关的Jar包

	<dependencies>
        
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.2version>
        dependency>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.41version>
        dependency>

		
        
        <dependency>
            <groupId>org.mybatis.generatorgroupId>
            <artifactId>mybatis-generator-coreartifactId>
            <version>1.3.5version>
        dependency>
    dependencies>

3. 创建数据库表

use mbg;
CREATE TABLE `people` (
  `id` int auto_increment,
  `age` int NOT NULL,
  `weight` double NOT NULL,
  `height` double NOT NULL,
  `name` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

4. IDEA中编写配置文件

编写mgb.xml与pom.xml放在同一目录

<generatorConfiguration>

    <context id="DB2Tables" targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressAllComments" value="true" />
        commentGenerator>
        
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mbg" userId="root"
                        password="88888">
        jdbcConnection>

        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        javaTypeResolver>

        
        <javaModelGenerator targetPackage="com.server.bean"
                            targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        javaModelGenerator>

        
        <sqlMapGenerator targetPackage="mapper" targetProject=".\src\main\resources">
            <property name="enableSubPackages" value="true" />
        sqlMapGenerator>

        
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.server.dao" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
        javaClientGenerator>

        
        <table tableName="people" domainObjectName="People"/>
    context>
generatorConfiguration>

5. 编写生成代码

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultShellCallback;

public class Main {

    public static void main(String[] args) throws Exception {
        List<String> warnings = new ArrayList<String>();
        boolean overwrite = true;
        File configFile = new File("mbg.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(configFile);
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
                callback, warnings);
        myBatisGenerator.generate(null);
    }
}

6. 执行

执行前：

执行后：

生成对应的mapper文件：

Mapper接口：

bean类：

7. 编写测试代码：
   插入成功，说明逆向工程成功
   
   demo的github链接：
   https://github.com/Parallelline1996/DailyCoding/tree/master/MBG