MyBatis动态SQL foreach标签实现批量插入

需求:查出给定id的记录:

 

        SELECT * FROM tb1_emplyee WHERE id IN
        
            #{item_id}
        

关于foreach标签,有几个属性应该注意一下:

 

 

        collection：指定要遍历的集合：
        list类型的参数会特殊处理封装在map中，map的key就叫list
        item：将当前遍历出的元素赋值给指定的变量
        separator:每个元素之间的分隔符
        open：遍历出所有结果拼接一个开始的字符
        close:遍历出所有结果拼接一个结束的字符
        index:索引。遍历list的时候是index就是索引，item就是当前值
        遍历map的时候index表示的就是map的key，item就是map的值
        #{变量名}就能取出变量的值也就是当前遍历出的元素

测试方法:

 

 

@Test
	public void testDynamicSqlTest() throws IOException{
		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
		//1、获取到的SqlSession不会自动提交数据
		SqlSession openSession = sqlSessionFactory.openSession();
		try
		{
			    EmployeeMapperDymanicSQL mapper=openSession.getMapper(EmployeeMapperDymanicSQL.class);
				/*Employee employee=new Employee(1,"lili",null,"1");*/
				List emps=mapper.getEmpsByConditionForeach(Arrays.asList(1,2,3,4));
			    for (Employee e:emps){
					System.out.println(e);
				}

		}
		finally {
			openSession.close();
		}
	}

 

 

foreach标签也可以实现实现批量插入(删除)数据:

 

 

这里以批量插入数据为例:

 

        INSERT INTO tb1_emplyee(last_name,email,gender,d_id)
        VALUES 
        
            (#{emp.lastName},#{emp.email},#{emp.gender},#{emp.dept.id})
        

对应的接口:

 

 

  public void addEmps(@Param("emps")List emps);

测试方法

@Test
	public void testBatchSave() throws IOException{
		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
		//1、获取到的SqlSession不会自动提交数据
		SqlSession openSession = sqlSessionFactory.openSession();
		try
		{
			EmployeeMapperDymanicSQL mapper=openSession.getMapper(EmployeeMapperDymanicSQL.class);
			List emps=new ArrayList();
			emps.add(new Employee(null,"Eminem","[email protected]","1",new Department(1)));
			emps.add(new Employee(null,"2Pac","[email protected]","1",new Department(1)));
			mapper.addEmps(emps);
			openSession.commit();
		}
		finally {
			openSession.close();
		}

	}