MyBatis 传入参数parameterType详解

  在MyBatis的select、insert、update、delete这些元素中都提到了parameterType这个属性。MyBatis现在可以使用的parameterType有基本数据类型和JAVA复杂数据类型

    基本数据类型：包含int,String,Date等。基本数据类型作为传参，只能传入一个。通过#{参数名} 即可获取传入的值
    复杂数据类型：包含JAVA实体类、Map。通过#{属性名}或#{map的KeyName}即可获取传入的值



    基本数据类型参数示例：

    根据班级ID查询教师列表

    xml文件

        <select id="selectTeacher" parameterType="int" resultType="com.myapp.domain.Teacher"> 
            select * from Teacher where c_id=#{id} 
        </select> 


    java代码

        List<Teacher> tList = teacherMapper.selectTeacher(2);   
        for (Teacher entityTemp : tList) {   
            System.out.println(entityTemp.toString());   
        }   

    JAVA实体类型参数示例：

        <select id="selectTeacher" parameterType="com.myapp.domain.Teacher" resultType="com.myapp.domain.Teacher"> 
            select * from Teacher where c_id=#{id} 
        </select> 


        java代码 
         
        Teacher queryTeacher=new Teacher(); 
        queryTeacher.setId(2); 
        List<Teacher> tList = teacherMapper.selectTeacher(queryTeacher);   
        for (Teacher entityTemp : tList) {   
            System.out.println(entityTemp.toString()); } 

    Map参数示例：
        <select id="selectTeacher" parameterType="Map" resultType="com.myapp.domain.Teacher"> 
            select * from Teacher where c_id=#{id} and sex=#{sex} 
        </select> 

        java代码 
         
        Map<String,String> map=new HasMap<String,String>(); 
        map.put("id","2"); 
        map.put("sex","男"); 
        List<Teacher> tList = teacherMapper.selectTeacher(map);   
        for (Teacher entityTemp : tList) {   
            System.out.println(entityTemp.toString()); } 

另外MyBatis还提供了一个使用注解来参入多个参数的方式。这种方式需要在接口的参数上添加@Param注解

示例：

接口方法

    public List<Teacher> selectTeacher(@Param(value="id") String id,@Param(value="sex") String sex); 


XML文件

    <select id="selectTeacher"  resultType="com.myapp.domain.Teacher"> 
        select * from Teacher where c_id=#{id} and sex=#{sex} 
    </select> 


测试代码

    List<Teacher> tList = teacherMapper.selectTeacher("2","男");   
    for (Teacher entityTemp : tList) {   
        System.out.println(entityTemp.toString());