逆向工程。

最新推荐文章于 2025-04-13 22:25:59 发布

原创最新推荐文章于 2025-04-13 22:25:59 发布 · 1k 阅读

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#mybatis

正向工程：先创建java实体类，有框架负责根据实体类生成数据库表。Hibernate是支持正向工程

逆向工程：先创建数据库表，由框架负责根据数据库表，反向生成如下资源：

⑴Java实体类

⑵Mapper接口

⑶Mapper映射文件

注意：逆向工程生成的都是单表资源

13.1、创建逆向工程的步骤

⑴添加依赖


<build>
    
    <plugins>
        
        <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.0</version>
            
            <dependencies>
                
                <dependency>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-core</artifactId>
                    <version>1.3.2</version>
                </dependency>
                
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.6</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>

⑵配置MyBatis的核心配置文件

配置pojo包和mapper包

⑶创建逆向工程的配置文件,该文件文件名必须是：generatorConfig.xml

<?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="DB2Tables" targetRuntime="MyBatis3">
        
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mybatis_demo"
                        userId="root"
                        password="root">
        </jdbcConnection>
        
        <javaModelGenerator targetPackage="com.qcby.mybatis.pojo"
                            targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        
        <sqlMapGenerator targetPackage="com.qcby.mybatis.mapper"
                         targetProject=".\src\main\resources">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>
        
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.qcby.mybatis.mapper" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>
        
        
        
        <table tableName="emp" domainObjectName="Emp"/>
        <table tableName="dept" domainObjectName="Dept"/>
    </context>
</generatorConfiguration>

13.2测试

/**
* 根据主键查询
*/
@Test
public void testSelectByPrimaryKey(){

    Emp emp = empMapper.selectByPrimaryKey(1);
    System.out.println(emp);
}

/**
* 带条件查询
*/
@Test
public void testSelectByExample(){
    List<Emp> emps = empMapper.selectByExample(null);
    emps.forEach(System.out::println);
}

@Test
public void testSelectByExample2(){
    EmpExample example = new EmpExample();
    example.createCriteria().andEmpNameEqualTo("李四").andAgeGreaterThanOrEqualTo(22);

    List<Emp> emps = empMapper.selectByExample(example);
    emps.forEach(System.out::println);
}

@Test
public void testSelectByExample3(){
    EmpExample example = new EmpExample();
    example.createCriteria().andEmpNameEqualTo("王五").andAgeGreaterThanOrEqualTo(22);
    example.or().andSexEqualTo("男");

    List<Emp> emps = empMapper.selectByExample(example);
    emps.forEach(System.out::println);
}

@Test
public void testUpdateByPrimaryKey(){
    Emp emp = new Emp(2,"小张",null,"女");
    // int i = empMapper.updateByPrimaryKey(emp);
    // if(i>0){
    //     System.out.println("更新成功");
    // }else {
    //     System.out.println("更新失败");
    // }

    int i = empMapper.updateByPrimaryKeySelective(emp);
    if(i>0){
        System.out.println("更新成功");
    }else {
        System.out.println("更新失败");
    }
}