1.测试数据

1.表结构SQL

CREATE TABLE `test` (`id` int DEFAULT NULL,`u_id` int DEFAULT NULL,`p_u_id` int DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

2.数据SQL

INSERT INTO test (id,u_id,p_u_id) VALUES(1,1,0),(2,2,0),(3,3,0),(4,11,1),(5,12,1),(6,21,2),(7,22,2),(8,211,21),(9,221,22),(10,222,22),(11,223,22),(12,2231,223),(13,2232,223),(14,0,-1);

3.查询表数据

select * from test;

2.实现代码

1.pojo代码

@TableName("test")
@Data
public class Test implements Serializable {private Integer id;private Integer uId;private Integer pUId;@TableField(exist = false)private List<Test> testChains;@TableField(exist =false)private String treeId;}

2.service层代码

    @Overridepublic List<String> treeIds() {List<Test> list = this.list();return list.stream().filter(e -> e.getPUId() == -1).peek((tId) -> {tId.setTestChains(getChildren(tId, list));}).toList();}private List<Test> getChildren(Test test, List<Test> all) {return all.stream().filter(x->x.getPUId() != null).filter(categoryEntity -> {return categoryEntity.getPUId().equals(test.getUId());}).peek(treeId -> {treeId.setTestChains(getChildren(treeId, all));}).collect(Collectors.toList());}
}

3.测试结果

[{"id": 14,"testChains": [{"id": 1,"testChains": [{"id": 4,"testChains": [],"treeId": null,"puid": 1,"uid": 11},{"id": 5,"testChains": [],"treeId": null,"puid": 1,"uid": 12}],"treeId": null,"puid": 0,"uid": 1},{"id": 2,"testChains": [{"id": 6,"testChains": [{"id": 8,"testChains": [],"treeId": null,"puid": 21,"uid": 211}],"treeId": null,"puid": 2,"uid": 21},{"id": 7,"testChains": [{"id": 9,"testChains": [],"treeId": null,"puid": 22,"uid": 221},{"id": 10,"testChains": [],"treeId": null,"puid": 22,"uid": 222},{"id": 11,"testChains": [{"id": 12,"testChains": [],"treeId": null,"puid": 223,"uid": 2231},{"id": 13,"testChains": [],"treeId": null,"puid": 223,"uid": 2232}],"treeId": null,"puid": 22,"uid": 223}],"treeId": null,"puid": 2,"uid": 22}],"treeId": null,"puid": 0,"uid": 2},{"id": 3,"testChains": [],"treeId": null,"puid": 0,"uid": 3}],"treeId": null,"puid": -1,"uid": 0}
]

3.获取父ID层级

1.pojo代码

@TableName("test")
@Data
public class Test implements Serializable {private Integer id;private Integer uId;private Integer pUId;@TableField(exist = false)private List<Test> testChains;@TableField(exist =false)private String treeId;}

2.service层代码

 @Overridepublic List<String> treeIds() {List<Test> list = this.list();List<Test> collect = list.stream().peek((tId) -> {tId.setTreeId(tId.getUId().toString());tId.setTestChains(getChildren(tId, list));}).toList();return collect.stream().map(Test::getTreeId).toList();}private List<Test> getChildren(Test test, List<Test> all) {return all.stream().filter(x->x.getPUId() != null).filter(categoryEntity -> {return categoryEntity.getPUId().equals(test.getUId());}).peek(treeId -> {treeId.setTreeId((test.getTreeId() == null? test.getUId() : test.getTreeId())+"/"+treeId.getUId());treeId.setTestChains(getChildren(treeId, all));}).collect(Collectors.toList());}

3.测试结果

["0/1","0/2","0/3","0/1/11","0/1/12","0/2/21","0/2/22","0/2/21/211","0/2/22/221","0/2/22/222","0/2/22/223","0/2/22/223/2231","0/2/22/223/2232","0"
]