Fuzzy query in Map pass-by-value and object pass-by-value

一、在MapFuzzy query in pass-by-value

• 适用于字段或者参数过多,我们应当考虑使用Map!
• 在xml的sql语句当中,parametertaypeThe type of directly writemap,No need to write the full class name of the entity class.
• #{} Variables can be named arbitrarily within parentheses,It is no longer necessary to match the variable name of the entity class.
• 在测试时,只需要 new 一个hashmap ,Treat variables inside parentheses as key值,valuefor the value you want to add,然后put进map里就可以了.Saves the step of building multiple constructors.

1、Mapper接口

 List<Map> UserList(Map<String,Object> map);

2、XML

	<select id="UserList" resultType="map">
        select *
        from mybatis01.user where name like #{value};
    </select>

3、Test

	@Test
    public void getUserList() {
    
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        HashMap<String, Object> map = new HashMap<>();
        map.put("value", "%亚%");
        List<Map> maps = mapper.UserList(map);
        for (Map map1 : maps) {
    
            System.out.println(map1);
        }
		//In addition, deletion and modification, the transaction must be submitted！ sqlSession.commit();
        sqlSession.close();
    }

二、Fuzzy query in object pass-by-value

• bound to the interfacexml中,#{} 括号里面的变量,Must correspond to the variable name defined by the entity class.
• 在测试类当中,要new对象时,The parameters of the constructor must also correspond one-to-one with the constructor created by the entity class.

1、实体类

package com.jin.pojo;

public class User {
    
    private int id;
    private String name;
    private String pwd;
	...
 // (无参、有参、get和set、toString)
 	...
}

2、Mapper接口

List<User> UserList02(String name);

3、XML

<select id="UserList02" resultType="com.jin.pojo.User" parameterType="String">
        select *
        from mybatis01.user where name like #{name};
    </select>

4、Test

 @Test
    public void UserList02(){
    
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.UserList02("%亚%");
        for (User user : userList) {
    
            System.out.println(user);
        }
        //In addition, deletion and modification, the transaction must be submitted！ sqlSession.commit();
        sqlSession.close();
    }

查询结果