Mybatis的基本使用（2） - 参数的传递与接收

 

  
    
        select * from t_user where id=#{value}
    

 
    
        insert into t_user(userName,password) values(#{userName},#{password})
    

  

    
    
        select * from t_user where userName=#{userName} and password=#{password}
    
 
2、mybatis中返回参数的接受问题 
2.1、返回简单类型的参数 
 

    
    
        select userName from t_user where id=#{value }
    

    
    
        select * from t_user where id=#{value }
    
 
2.3、返回集合类型的参数 
  
    
        select * from t_user
    

    
    
        SELECT id AS userId,userName AS username,PASSWORD AS passwd FROM t_user
    
 
2.4.2、通过建立映射关系来完成映射 
  
    
    
        
         
        
        
        
    
    
    
        SELECT * FROM t_user
    

1、编写User类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User1 {

    private int userId;
    private String username;
    private String passwd;
    private IdCard idCard;

}

2、编写IdCard类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class IdCard {
    private int id;
    private String address;
    private Date startTime;
    private Date endTime;
    private int userId;
}

3、编写映射关系和查询的描述

 

    
    
        
        
        
        
        
        

        
        
            
            
            
            
            
        

    


    
        SELECT * FROM t_user t1,t_idcard t2 WHERe t1.id=t2.userId AND t1.id=#{value }
    

 
4、测试
 
    
    @Test
    public void testFindUserIdCard() throws IOException {
        SqlSession sqlSession = JdbcUtils.getSqlSession();
        Object o = sqlSession.selectOne("UserMapper.findUserInfoById", 24);
        System.out.println("查询回来的数据是:"+o);
        JdbcUtils.close();
    }
 
2.6、映射关系的一对多的返回 
 
1、准备部门对象
 
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Dept {
    private int deptId;
    private String deptName;
    private String deptAddress;
    List employees;
}
 
2、准备员工对象
 
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Employee {
    private int empId;
    private String empName;
    private int gender;
}
 
3、准备配置文件和映射关系
 
  
    
    
    
       
        
        
        
        
        
            
            
            
            
            
        
    

    
       SELECT * FROM t_dept t1,t_emp t2 WHERe t1.deptId=t2.dId AND t1.deptId=#{value }
    

4、准备测试

    
    @Test
    public void testFindDeptByDeptId() throws IOException {
        SqlSession sqlSession = JdbcUtils.getSqlSession();
        Object o = sqlSession.selectOne("UserMapper.findDeptByDeptId", 1);
        System.out.println("查询回来的数据是:"+o);
        JdbcUtils.close();
    }