MyBatis逆向工程

回想一下MyBatis的基本操作，它需要实体类，自定义mapper接口以及mapper.xml配置文件。为了避免繁琐的工作量，MyBatis Generator，简称MBG，可自动生成框架所需的这些依赖，同时支持基本的CRUD操作，但是需要注意，MBG一般不要重复执行，否则会出问题。下面是引入MBG的基本操作：

一、新建maven项目，引入依赖：

<dependencies>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.5</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.20</version>
    </dependency>

    <dependency>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-core</artifactId>
        <version>1.4.0</version>
    </dependency>
</dependencies>

二、创建mbg配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <context id="testMBG" targetRuntime="MyBatis3">
        <!-- 连接池 -->
        <jdbcConnection
                driverClass="com.mysql.cj.jdbc.Driver"
                connectionURL="jdbc:mysql://localhost:3306/demo"
                userId="root"
                password=""
        ></jdbcConnection>
        <!-- 配置JavaBean生成策略 -->
        <javaModelGenerator targetPackage="com.wts.entity" targetProject="./src/main/java"></javaModelGenerator>
        <!-- 配置SQL映射文件生成策略 -->
        <sqlMapGenerator targetPackage="com.wts.entity" targetProject="./src/main/java"></sqlMapGenerator>
        <!-- 配置Mapper接口的生成策略 -->
        <javaClientGenerator targetPackage="com.wts.entity" targetProject="./src/main/java"></javaClientGenerator>
        <table tableName="user" domainObjectName="User"></table>
    </context>
</generatorConfiguration>

三、运行Generator：

public class MyTest {
    public static void main(String[] args) {
        List<String> warnings = new ArrayList<>();
        File configFile = new File(MyTest.class.getResource("generatorConfig.xml").getFile());
        ConfigurationParser configurationParser = new ConfigurationParser(warnings);
        Configuration configuration = null;
        try {
            configuration = configurationParser.parseConfiguration(configFile);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (XMLParserException e) {
            e.printStackTrace();
        }
        DefaultShellCallback callback = new DefaultShellCallback(true);
        MyBatisGenerator myBatisGenerator = null;
        try {
            myBatisGenerator = new MyBatisGenerator(configuration, callback, warnings);
        } catch (InvalidConfigurationException e) {
            e.printStackTrace();
        }
        try {
            myBatisGenerator.generate(null);
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

这都是固定写法，了解一下即可。