Mapper 接口如何传递多个参数

参考答案

Mapper接口传递多个参数的4种实现方式：

1.  接口中传多个参数，在 xml 中使用 #{param0}、#{param1}…

//方式一
//java
System.out.println("------ selectUserByParamIndex ------");
user = userMapper.selectUserByParamIndex(31, "javamianshi1");
System.out.println(user);
//xml
<select id="selectUserByParamIndex" resultType="javamianshi.po.User">
    select * from user where id = #{arg0} and name = #{arg1}
</select>

------ selectUserByParamIndex ------
User{id=31, name='javamianshi1', mc='null'}

2.  使用 @param 注解指定名称，在 xml 中使用 #{名称}

//方式二
//java
System.out.println("------ selectUserByAnnotation ------");
user = userMapper.selectUserByAnnotation(31, "javamianshi1");
System.out.println(user);
//xml
<select id="selectUserByAnnotation" resultType="javamianshi.po.User">
    select * from user where id = #{id} and name = #{name}
</select>

------ selectUserByAnnotation ------
User{id=31, name='javamianshi1', mc='null'}

3.  多个参数封装到 Java bean 中

//方式三
//java
System.out.println("------ selectUserByPo ------");
user = userMapper.selectUserByPo(new User(31, "javamianshi1"));
System.out.println(user);
//xml
<select id="selectUserByPo" resultType="constxiong.po.User" parameterType="javamianshi.po.User">
    select * from user where id = #{id} and name = #{name}
</select>

------ selectUserByPo ------
User{id=31, name='javamianshi1', mc='null'}

4.  多个参数指定 key，put 到 Map 中

//方式四
//java
System.out.println("------ selectUserByMap ------");
Map<String, Object> param = new HashMap<>();
param.put("id", 31);
param.put("name", "javamianshi1");
user = userMapper.selectUserByMap(param);
System.out.println(user);
//xml
<select id="selectUserByMap" resultType="javamianshi.po.User">
    select * from user where id = #{id} and name = #{name}
</select>

------ selectUserByMap ------
User{id=31, name='javamianshi1', mc='null'}

以上，是MyBatis面试题【Mapper接口如何传递多个参数】的参考答案。

输出，是最好的学习方法。

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