35、Mybatis进阶：逆向工程的编写

本文整合了http://www.gulixueyuan.com/my/course/43中的任务68，任务69，任务70

1映入逆向工程需要的jar包

2任务68：mgb文件的编写

<?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="MyBatis3Simple">
		<commentGenerator>
			<property name="suppressAllComments" value="true" />
		</commentGenerator>
		<!-- 配置数据库连接 -->
		<jdbcConnection driverClass="com.mysql.jdbc.Driver"
			connectionURL="jdbc:mysql://localhost:3306/ssm_crud" userId="root"
			password="123456">
		</jdbcConnection>

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

		<!-- 指定javaBean生成的位置 -->
		<javaModelGenerator targetPackage="com.atguigu.crud.bean"
			targetProject=".\src\main\java">
			<property name="enableSubPackages" value="true" />
			<property name="trimStrings" value="true" />
		</javaModelGenerator>

		<!--指定sql映射文件生成的位置 -->
		<sqlMapGenerator targetPackage="mapper" targetProject=".\src\main\resources">
			<property name="enableSubPackages" value="true" />
		</sqlMapGenerator>

		<!-- 指定dao接口生成的位置，mapper接口 -->
		<javaClientGenerator type="XMLMAPPER"
			targetPackage="com.atguigu.crud.dao" targetProject=".\src\main\java">
			<property name="enableSubPackages" value="true" />
		</javaClientGenerator>
		<!-- table指定每个表的生成策略 -->
		<table tableName="tbl_emp" domainObjectName="Employee"></table>
		<table tableName="tbl_dept" domainObjectName="Department"></table>
	</context>
</generatorConfiguration>

3逆向生成代码

	@Test
	public void testMbg() 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);
	}

4逆向生成更加复杂的工程

4.1只需要修改下mbg.xml中的一个属性值就可以了

4.2生成逆向代码

@Test
	public void testMbg() 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);
	}

4.3使用复杂的逆向工程实例

其中的criteria.andLastNameLike便是模糊查询，这有点类似于hibernate的hql

@Test
	public void testMyBatis3() throws IOException{
		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
		SqlSession openSession = sqlSessionFactory.openSession();
		try{
			EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
			//xxxExample就是封装查询条件的
			//1、查询所有
			//List<Employee> emps = mapper.selectByExample(null);
			//2、查询员工名字中有e字母的，和员工性别是1的
			//封装员工查询条件的example
			EmployeeExample example = new EmployeeExample();
			//创建一个Criteria，这个Criteria就是拼装查询条件
			//select id, last_name, email, gender, d_id from tbl_employee 
			//WHERE ( last_name like ? and gender = ? ) or email like "%e%"
			Criteria criteria = example.createCriteria();
			criteria.andLastNameLike("%e%");
			criteria.andGenderEqualTo("1");
			
			Criteria criteria2 = example.createCriteria();
			criteria2.andEmailLike("%e%");
			example.or(criteria2);
			
			List<Employee> list = mapper.selectByExample(example);
			for (Employee employee : list) {
				System.out.println(employee.getId());
			}
			
		}finally{
			openSession.close();
		}
	}

5.补充

如果觉得逆向生成的文件注释太多，可以设置一下，就不会生成注释了配置方式如下。在mbg文件中配置如下属性

		<commentGenerator>
			<property name="suppressAllComments" value="true" />
		</commentGenerator>

mgb全部类容如下

<?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">
		<commentGenerator>
			<property name="suppressAllComments" value="true" />
		</commentGenerator>
		<!-- 配置数据库连接 -->
		<jdbcConnection driverClass="com.mysql.jdbc.Driver"
			connectionURL="jdbc:mysql://localhost:3306/ssm_crud" userId="root"
			password="123456">
		</jdbcConnection>

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

		<!-- 指定javaBean生成的位置 -->
		<javaModelGenerator targetPackage="com.atguigu.crud.bean"
			targetProject=".\src\main\java">
			<property name="enableSubPackages" value="true" />
			<property name="trimStrings" value="true" />
		</javaModelGenerator>

		<!--指定sql映射文件生成的位置 -->
		<sqlMapGenerator targetPackage="mapper" targetProject=".\src\main\resources">
			<property name="enableSubPackages" value="true" />
		</sqlMapGenerator>

		<!-- 指定dao接口生成的位置，mapper接口 -->
		<javaClientGenerator type="XMLMAPPER"
			targetPackage="com.atguigu.crud.dao" targetProject=".\src\main\java">
			<property name="enableSubPackages" value="true" />
		</javaClientGenerator>
		<!-- table指定每个表的生成策略 -->
		<table tableName="tbl_emp" domainObjectName="Employee"></table>
		<table tableName="tbl_dept" domainObjectName="Department"></table>
	</context>
</generatorConfiguration>

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