mybatis

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());