mybatis模糊查询

SQLMapper接口

public interface SQLMapper {
 
    /*
    根据用户名 来模糊查询  用户信息
     */
    //  设置一个参数  有一个固定的访问方式
    List getUserByList(@Param("username") String username);
    
}

接口对应的映射文件

"1.0" encoding="UTF-8" ?>
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 
 
"com.atguigu.mybatis.mapper.SQLMapper">
 
    
 
    "getUserByLike" resultType="com.atguigu.mybatis.pojo.User">
        
        select  *  from  t_user  where  username like '%#{username}%'
 
    
 
 

建立测试类

public class SQLMapperTest {
 
 
    @Test
public  void  testGetUserByLike(){
 
 
      //获取 sqlSession 对象
        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
                         //  获取一个SQLMapper  对象
        SQLMapper mapper = sqlSession.getMapper(SQLMapper.class);
        //    根据a来调用,返回值是一个list集合
        List list = mapper.getUserByLike("a");
        System.out.println(list);
 
 
    }
}

三种模糊拼接方式

        select  *  from  t_user  where  username like '%${username}%'
      select * from t_user where  username  like  concat('%',#{username},'%')
          select  *  from  t_user where  username  like "%" #{username} "%"