MyBatis - parameterType - 多个参数

1. 将参数封装成一个域对象，底层 HashMap 还是一个：

1 User user=new User();
2 user.setUserName("taiyo");
3 user.setPassword("123");
4 checkUser(user);//为返回值类型为User

<select id="selectByUsernameAndPassword" resultType="user" parameterType="user">
    select * from user where username = #{username} and password = #{password};
</select>

2. 使用 HashMap 封装参数：

HashMap<String, Object> map = new HashMap<String, Object>();
map.put("username", "taiyo");
map.put("password", "123");
checkUser(map);

<select id="selectByUsernameAndPassword" resultType="user" parameterType="Map">
    select * from user where username = #{username} and password = #{password};
</select>

3. 在 UserMapper.java 接口中定义方法时在方法入参前加上 @param：

// interface UserMapper.java
User selectByUsernameAndPassword(@param("username") String username, @param("password") String password);

1 checkUser("taiyo", "123");

<select id="selectByUsernameAndPassword" resultType="user">
    select * from user where username = #{username} and password = #{password};
</select>