mybatis树型数据查询

一、表结构

CREATE TABLE `my_tree` (
	`test_id` VARCHAR(32) NOT NULL,
	`gjfl_name` VARCHAR(100) NULL DEFAULT NULL,
	`parent_id` VARCHAR(32) NULL DEFAULT NULL,
	`gjfl_level` INT(11) NULL DEFAULT NULL,
	PRIMARY KEY (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB;

二、构建数据

INSERT INTO `my_tree` VALUES ('1', '1', '0', '1');
INSERT INTO `my_tree` VALUES ('2', '2', '1', '2');
INSERT INTO `my_tree` VALUES ('3', '3', '0', '1');
INSERT INTO `my_tree` VALUES ('4', '4', '3', '2');
INSERT INTO `my_tree` VALUES ('5', '5', '4', '3');
INSERT INTO `my_tree` VALUES ('6', '6', '2', '3');
INSERT INTO `my_tree` VALUES ('7', '7', '3', '2');

三、实体

@Table(name = "my_tree")
public class MyTree implements Serializable {
    @Id
    @Column(name = "test_id")
    private String testId;

    @Column(name = "gjfl_name")
    private String gjflName;

    @Column(name = "parent_id")
    private String parentId;

    @Column(name = "gjfl_level")
    private Integer gjflLevel;

    private List childrenList;//注意这里
//忽略setter、getter方法，使用lombok可以生成setter、getter
}

四、mapper配置
注意collection里的配置：javaType、 column、select

    
    
    
    
    
  
  
 
    
      
      
      
      
    
  
  
    SELECT * FROM my_tree where parent_id = #{testId} <--这里是父级ID-->
  

五、DAO层

public interface MyTreeMapper {

        List findLevel(String param);

}

service及controller层与平常没有差别
结果

"list":[
	{"testId":"1","gjflName":"1","parentId":"0","gjflLevel":1,
		"childrenList":[
			{"testId":"2","gjflName":"2","parentId":"1","gjflLevel":2,
				"childrenList":[
					{"testId":"6","gjflName":"6","parentId":"2","gjflLevel":3,"childrenList":[]}
				]
			}
		]
	},
	{"testId":"3","gjflName":"3","parentId":"0","gjflLevel":1,
		"childrenList":[
			{"testId":"4","gjflName":"4","parentId":"3","gjflLevel":2,
				"childrenList":[
					{"testId":"5","gjflName":"5","parentId":"4","gjflLevel":3,"childrenList":[]}
				]
			},
			{"testId":"7","gjflName":"7","parentId":"3","gjflLevel":2,"childrenList":[]}
		]
	}
]