MyBatis 傳入參數parameterType詳解

在MyBatis的select、insert、update、delete這些元素中都提到了parameterType這個屬性。MyBatis現在可以使用的parameterType有基本數據類型和JAVA複雜數據類型

基本數據類型：包含int,String,Date等。基本數據類型作爲傳參，只能傳入一個。通過#{參數名} 即可獲取傳入的值
複雜數據類型：包含JAVA實體類、Map。通過#{屬性名}或#{map的KeyName}即可獲取傳入的值



基本數據類型參數示例：

根據班級ID查詢教師列表

xml文件

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


java代碼

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

JAVA實體類型參數示例：

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


java代碼

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

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

java代碼

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還提供了一個使用註解來參入多個參數的方式。這種方式需要在接口的參數上添加@Param註解

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>


測試代碼

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