MyBatis逆向工程 Generator

冷不防 2023-10-01 20:39 15阅读 0赞

*  正向工程：先创建Java实体类，由框架负责根据实体类生成数据库表。Hibernate是支持正向工程  
    的。
 *  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：
    
    Java实体类  
    Mapper接口  
    Mapper映射文件

1.  添加依赖和插件 pom

<dependencies>
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.7</version>
            </dependency>
        </dependencies>
    
        <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>com.mchange</groupId>
                            <artifactId>c3p0</artifactId>
                            <version>0.9.2</version>
                        </dependency> 
                        <dependency>
                            <groupId>mysql</groupId>
                            <artifactId>mysql-connector-java</artifactId>
                            <version>5.1.8</version>
                        </dependency>
                    </dependencies>
                </plugin>
            </plugins>
        </build>

1.  创建MyBatis的核心配置文件 mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        
        <properties resource="jdbc.properties"></properties>
        <settings>
            
            <setting name="mapUnderscoreToCamelCase" value="true"/>
            
            <setting name="lazyLoadingEnabled" value="true"/>
        </settings>
        <typeAliases>
            
            
            
            
            <package name="com.atguigu.mybatis.pojo"/>
        </typeAliases>
        
        <environments default="mysql_test">
            
            <environment id="mysql_test">
                
                <transactionManager type="JDBC"/>
                
                <dataSource type="POOLED">
                    
                    <property name="driver" value="${jdbc.driver}"/>
                    
                    <property name="url" value="${jdbc.url}"/>
                    
                    <property name="username" value="${jdbc.username}"/>
                    
                    <property name="password" value="${jdbc.password}"/>
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            
            
            <package name="com.atguigu.mybatis.mapper"/>
        </mappers>
    </configuration>

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://152.136.208.110:3306/MyBatis
    jdbc.username=root
    jdbc.password=creation

1.  创建逆向工程的配置文件 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://152.136.208.110:3306/mybatis"
                            userId="root"
                            password="creation">
    
            </jdbcConnection>
            
            <javaModelGenerator targetPackage="com.atguigu.mybatis.pojo" targetProject=".\src\main\java">
                <property name="enableSubPackages" value="true"/>
                <property name="trimStrings" value="true"/>
            </javaModelGenerator>
            
            <sqlMapGenerator targetPackage="com.atguigu.mybatis.mapper" targetProject=".\src\main\resources">
                <property name="enableSubPackages" value="true"/>
            </sqlMapGenerator>
            
            <javaClientGenerator type="XMLMAPPER" targetPackage="com.atguigu.mybatis.mapper" targetProject=".\src\main\java">
                <property name="enableSubPackages" value="true"/>
            </javaClientGenerator>
            
            
            
            <table tableName="t_emp" domainObjectName="Emp"/>
            <table tableName="t_dept" domainObjectName="Dept"/>
        </context>
    </generatorConfiguration>

1.  执行MBG插件的generate目标  
    ![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5bCn5LiK5pyJ5Yac_size_19_color_FFFFFF_t_70_g_se_x_16]  
    ![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5bCn5LiK5pyJ5Yac_size_19_color_FFFFFF_t_70_g_se_x_16 1]
2.  QBC查询

加入依赖

<dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.3</version>
            </dependency>
            
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>

@Test 
    public void testMBG() throws IOException {
         
    	InputStream is = Resources.getResourceAsStream("mybatis-config.xml"); SqlSession sqlSession = new SqlSessionFactoryBuilder().build(is).openSession(true);
    	EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); 
    	EmpExample empExample = new EmpExample(); 
    	//创建条件对象，通过andXXX方法为SQL添加查询添加，每个条件之间是and关系 
    	empExample.createCriteria().andEnameLike("a").andAgeGreaterThan(20).andDidIsNot Null(); 
    	//将之前添加的条件通过or拼接其他条件 
    	empExample.or().andSexEqualTo("男"); 
    	List<Emp> list = mapper.selectByExample(empExample); 
    	for (Emp emp : list) {
         
    		System.out.println(emp); 
    	} 
    }

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5bCn5LiK5pyJ5Yac_size_20_color_FFFFFF_t_70_g_se_x_16]

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