【Java】MyBatis应用（四）逆向工程

正文索引 [隐藏]

MyBatis框架需要：实体类、自定义Mapper接口、Mapper.xml
传统发开中上述三个组件需要开发者手动创建，逆向工程可以帮助开发者自动创建三个组件，减轻开发者的工作量，提高工作效率

如何使用逆向工程

MyBatis Generator，简称MBG，是一个专门为Mybatis框架开发者定制的代码生成器，可自动生成MaBatis框架所需的实体类、Mapper接口和Mappler.xml，支持基本的CRUD操作，但是一些相对复杂的SQL需要开发者自己来完成

  • 新建Maven工程，pom.xml
    • <dependencies>
    
        <dependency>
    
            <groupId>org.mybatis</groupId>
    
            <artifactId>mybatis</artifactId>
    
            <version>3.4.6</version>
    
        </dependency>
    
        <dependency>
    
            <groupId>mysql</groupId>
    
            <artifactId>mysql-connector-java</artifactId>
    
            <version>8.0.21</version>
    
        </dependency>
    
        <dependency>
    
            <groupId>org.mybatis.generator</groupId>
    
            <artifactId>mybatis-generator</artifactId>
    
            <version>1.3.2</version>
    
        </dependency>
    
    </dependencies>
  • 创建MBG配置文件generatorConfig.xml

    • 1、jdbcConnect配置数据库连接信息
    2、javaModelGenerator配置JavaBean的生成策略
    3、sqlMapGenerator配置SQL映射文件生成策略
    4、JavaClientGenerator配置Mapper接口的生成策略
    5、table配置目标数据表(tbaleName：表名,domainObjectName：JavaBean类名)

    <?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="mybatis" targetRuntime="MyBatis3">
    
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
    
                        connectionURL="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"
    
                        userId="root" password="123456">
    
        </jdbcConnection>
    
        <javaModelGenerator targetPackage="com.mybatistest.entity" targetProject=".\src\main\java">
    
        </javaModelGenerator>
    
        <sqlMapGenerator targetPackage="com.mybatistest.repository" targetProject=".\src\main\java">
    
        </sqlMapGenerator>
    
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.mybatistest.repository" targetProject=".\src\main\java">
    
        </javaClientGenerator>
    
        <table tableName="t_user" domainObjectName="User">
    
        </table>
    
    </context>
    
</generatorConfiguration>

  • 创建Generator执行类

    • package com.mybatis.test;
    
import org.mybatis.generator.api.MyBatisGenerator;
    
import org.mybatis.generator.config.Configuration;
    
import org.mybatis.generator.config.xml.ConfigurationParser;
    
import org.mybatis.generator.exception.InvalidConfigurationException;
    
import org.mybatis.generator.exception.XMLParserException;
    
import org.mybatis.generator.internal.DefaultShellCallback;
    
import java.io.File;
    
import java.io.IOException;
    
import java.sql.SQLException;
    
import java.util.ArrayList;
    
import java.util.List;
    
public class Main {
    
    public static void main(String[] args) {
    
        List<String>warings = new ArrayList<String>();
    
        boolean overwrite = true;
    
        String genCig = "/generatorConfig.xml";
    
        File configFile = new File(Main.class.getResource(genCig).getFile());
    
        ConfigurationParser configurationParser = new ConfigurationParser(warings);
    
        Configuration configuration = null;
    
        try {
    
            configuration = configurationParser.parseConfiguration(configFile);
    
        } catch (IOException e) {
    
            e.printStackTrace();
    
        } catch (XMLParserException e) {
    
            e.printStackTrace();
    
        }
    
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
    
        MyBatisGenerator myBatisGenerator = null;
    
        try {
    
            myBatisGenerator = new MyBatisGenerator(configuration,callback,warings);
    
        } catch (InvalidConfigurationException e) {
    
            e.printStackTrace();
    
        }
    
        try {
    
            myBatisGenerator.generate(null);
    
        } catch (SQLException throwables) {
    
            throwables.printStackTrace();
    
        } catch (IOException e) {
    
            e.printStackTrace();
    
        } catch (InterruptedException e) {
    
            e.printStackTrace();
    
        }
    
    }
    
}
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