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java树结构查询及分页_java树形结构查询

作者：繁依Fanyi0 | 2024-05-03 06:41:48

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java树形结构查询

目录

1、简单表结构示例：

结果展示：

实体类TestTree

controller

service

mapper

2、多层次使用此方法也可以查询出树形结构

示例：

3、根据根节点分页

TreeEntity

BaseEntity 

sysDept

SysdeptPlus

serviceImpl

1、简单表结构示例：

结果展示：

  1. {
  2.     "success": true,
  3.     "message": "操作成功！",
  4.     "code": 200,
  5.     "result": [
  6.         {
  7.             "id": 1,
  8.             "pid": 0,
  9.             "name": "中国",
  10.             "code": "0001",
  11.             "children": [
  12.                 {
  13.                     "id": 2,
  14.                     "pid": 1,
  15.                     "name": "河南",
  16.                     "code": "0002",
  17.                     "children": [
  18.                         {
  19.                             "id": 4,
  20.                             "pid": 2,
  21.                             "name": "周口",
  22.                             "code": "0021",
  23.                             "children": []
  24.                         },
  25.                         {
  26.                             "id": 5,
  27.                             "pid": 2,
  28.                             "name": "郑州",
  29.                             "code": "0022",
  30.                             "children": []
  31.                         }
  32.                     ]
  33.                 },
  34.                 {
  35.                     "id": 3,
  36.                     "pid": 1,
  37.                     "name": "台湾",
  38.                     "code": "0003",
  39.                     "children": [
  40.                         {
  41.                             "id": 6,
  42.                             "pid": 3,
  43.                             "name": "台北",
  44.                             "code": "0031",
  45.                             "children": []
  46.                         }
  47.                     ]
  48.                 },
  49.                 {
  50.                     "id": 7,
  51.                     "pid": 1,
  52.                     "name": "北京",
  53.                     "code": "0004",
  54.                     "children": []
  55.                 }
  56.             ]
  57.         }
  58.     ],
  59.     "resultTwo": null,
  60.     "resultThree": null,
  61.     "timestamp": 1687765801212
  62. }

实体类TestTree

  1. @Data
  2. @TableName("test_tree")
  3. @Accessors(chain = true)
  4. @ApiModel(value="测试树", description="测试树")
  5. public class TestTree {
  6.  
  7.     @ApiModelProperty(value = "ID")
  8.     private Integer id;
  9.  
  10.     @ApiModelProperty(value = "父id")
  11.     private Integer pid;
  12.  
  13.     @ApiModelProperty(value = "姓名")
  14.     private String name;
  15.  
  16.     @ApiModelProperty(value = "编码")
  17.     private String code;
  18.  
  19.     @TableField(exist = false)
  20.     private List<TestTree> children;
  21.  
  22. }

controller

  1. @Slf4j
  2. @Api(tags = "测试树")
  3. @RestController
  4. @RequestMapping("/test")
  5. public class TestTreeController {
  6. 	@Resource
  7. 	private TestTreeService testTreeService;
  8.  
  9. 	@ApiOperation(value = "测试树",notes = "测试树")
  10. 	@GetMapping("/selectTree")
  11. 	public Result<Object> selectTree() {
  12. 		Result<Object> result = testTreeService.selectTree();
  13. 		return Result.ok(result);
  14. 	}
  15. }

 service

  1. public interface TestTreeService {
  2.     Result<Object> selectTree();
  3.  
  4. }
  5.  
  6.  
  7. @Service
  8. public class TestTreeServiceImpl implements TestTreeService {
  9.     @Resource
  10.     private TestTreeMapper testTreeMapper;
  11.  
  12.     @Override
  13.     public Result<Object> selectTree() {
  14.         List<TestTree> testTreeList=this.testTreeMapper.selectTree();
  15.  
  16.         List<TestTree> testTrees = testTreeList.stream().filter(testTree -> 0 == testTree.getPid())
  17.                 .peek(testTree -> testTree.setChildren(createChildList(testTree, testTreeList)))
  18.                 .collect(Collectors.toList());
  19.         return Result.ok(testTrees);
  20.     }
  21.  
  22.     /**
  23.      * @param testTree  父级
  24.      * @param testTreeList 对应的list
  25.      * @return
  26.      */
  27.     private static List<TestTree> createChildList(TestTree testTree, List<TestTree> testTreeList) {
  28.  
  29.         return testTreeList.stream().filter(model -> testTree.getId().equals(model.getPid()))
  30.                 .peek(model -> model.setChildren(createChildList(model, testTreeList)))
  31.                 .collect(Collectors.toList());
  32.     }
  33.  
  34. }

 mapper

sql：select * from test_tree 

2、多层次使用此方法也可以查询出树形结构

示例：

  1. {
  2.     "success": true,
  3.     "message": "操作成功！",
  4.     "code": 200,
  5.     "result": [
  6.       {
  7.         "id": 1,
  8.         "pid": 0,
  9.         "name": "中国",
  10.         "code": "0001",
  11.         "children": [
  12.           {
  13.             "id": 2,
  14.             "pid": 1,
  15.             "name": "河南",
  16.             "code": "0002",
  17.             "children": [
  18.               {
  19.                 "id": 4,
  20.                 "pid": 2,
  21.                 "name": "周口",
  22.                 "code": "0021",
  23.                 "children": [
  24.                   {
  25.                     "id": 10,
  26.                     "pid": 4,
  27.                     "name": "郸城县",
  28.                     "code": "0211",
  29.                     "children": [
  30.                       {
  31.                         "id": 12,
  32.                         "pid": 10,
  33.                         "name": "汲冢镇",
  34.                         "code": "2111",
  35.                         "children": []
  36.                       },
  37.                       {
  38.                         "id": 13,
  39.                         "pid": 10,
  40.                         "name": "李楼乡",
  41.                         "code": "2112",
  42.                         "children": []
  43.                       }
  44.                     ]
  45.                   },
  46.                   {
  47.                     "id": 11,
  48.                     "pid": 4,
  49.                     "name": "沈丘县",
  50.                     "code": "0212",
  51.                     "children": []
  52.                   }
  53.                 ]
  54.               },
  55.               {
  56.                 "id": 5,
  57.                 "pid": 2,
  58.                 "name": "郑州",
  59.                 "code": "0022",
  60.                 "children": []
  61.               }
  62.             ]
  63.           },
  64.           {
  65.             "id": 3,
  66.             "pid": 1,
  67.             "name": "台湾",
  68.             "code": "0003",
  69.             "children": [
  70.               {
  71.                 "id": 6,
  72.                 "pid": 3,
  73.                 "name": "台北",
  74.                 "code": "0031",
  75.                 "children": []
  76.               }
  77.             ]
  78.           },
  79.           {
  80.             "id": 7,
  81.             "pid": 1,
  82.             "name": "北京",
  83.             "code": "0004",
  84.             "children": []
  85.           }
  86.         ]
  87.       },
  88.       {
  89.         "id": 8,
  90.         "pid": 0,
  91.         "name": "俄罗斯",
  92.         "code": "1001",
  93.         "children": [
  94.           {
  95.             "id": 9,
  96.             "pid": 8,
  97.             "name": "莫斯科",
  98.             "code": "1011",
  99.             "children": []
  100.           }
  101.         ]
  102.       }
  103.     ],
  104.   "resultTwo": null,
  105.   "resultThree": null,
  106.   "timestamp": 1687766628068
  107. }

3、根据根节点分页

TreeEntity<T>

  1. @Data
  2. @EqualsAndHashCode(callSuper = true)
  3. public class TreeEntity<T> extends BaseEntity {
  4.  
  5.     private static final long serialVersionUID = 1L;
  6.  
  7.     /**
  8.      * 父菜单名称
  9.      */
  10.     @TableField(exist = false)
  11.     private String parentName;
  12.  
  13.     /**
  14.      * 父菜单ID
  15.      */
  16.     private Long parentId;
  17.  
  18.     /**
  19.      * 子部门
  20.      */
  21.     @TableField(exist = false)
  22.     private List<T> children = new ArrayList<>();
  23. }

 BaseEntity 

  1. @Data
  2. public class BaseEntity implements Serializable {
  3.  
  4.     private static final long serialVersionUID = 1L;
  5.  
  6.     /**
  7.      * 搜索值
  8.      */
  9.     @JsonIgnore
  10.     @TableField(exist = false)
  11.     private String searchValue;
  12.  
  13.  
  14.     /**
  15.      * 创建者
  16.      */
  17.     @TableField(fill = FieldFill.INSERT)
  18.     @ApiModelProperty(value = "创建人")
  19.     private String createName;
  20.  
  21.     /**
  22.      * 创建时间
  23.      */
  24.     @TableField(fill = FieldFill.INSERT)
  25.     @ApiModelProperty(value = "创建时间")
  26.     private LocalDateTime createTime;
  27.  
  28.     /**
  29.      * 更新者
  30.      */
  31.     @JsonFormat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
  32.     @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
  33.     @TableField(fill = FieldFill.INSERT_UPDATE)
  34.     @ApiModelProperty(value = "更新人")
  35.     private String updateName;
  36.  
  37.     /**
  38.      * 更新时间
  39.      */
  40.     @JsonFormat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
  41.     @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
  42.     @TableField(fill = FieldFill.INSERT_UPDATE)
  43.     @ApiModelProperty(value = "更新时间")
  44.     private LocalDateTime updateTime;
  45.  
  46.     /**
  47.      * 开始时间
  48.      */
  49.     @TableField(exist = false)
  50.     @ApiModelProperty(value = "时间查询开始时间")
  51.     private String beginCreateTime;
  52.  
  53.     /**
  54.      * 结束时间
  55.      */
  56.     @TableField(exist = false)
  57.     @ApiModelProperty(value = "时间查询结束时间")
  58.     private String endCreateTime;
  59.  
  60.     /**
  61.      * 页码
  62.      */
  63.     @TableField(exist = false)
  64.     @ApiModelProperty(value = "页码")
  65.     private Integer pageNum = 1;
  66.  
  67.     /**
  68.      * 条数
  69.      */
  70.     @TableField(exist = false)
  71.     @ApiModelProperty(value = "每页条数")
  72.     private Integer pageSize = 10;
  73.  
  74.     /**
  75.      * 请求参数
  76.      */
  77.     @JsonInclude(JsonInclude.Include.NON_EMPTY)
  78.     // 在序列化Java对象为JSON时，只有属性值不为null，或者如果属性是集合或数组，则至少包含一个元素，或者如果属性是字符串，则不是空字符串，这些属性才会被包含在生成的JSON中。
  79.     @TableField(exist = false)
  80.     private Map<String, Object> params = new HashMap<>();
  81.  
  82. }

sysDept

  1. @Data
  2. @EqualsAndHashCode(callSuper = true)
  3. @TableName("sys_dept")
  4. @NoArgsConstructor
  5. @AllArgsConstructor
  6. public class SysDept extends TreeEntity<SysDept> {
  7.     private static final long serialVersionUID = 1L;
  8.  
  9.     /**
  10.      * 部门ID
  11.      */
  12.     @TableId(value = "dept_id")
  13.     private Long deptId;
  14.  
  15.     /**
  16.      * 部门编码
  17.      */
  18.     @NotBlank(message = "部门编码不能为空")
  19.     @Size(min = 0, max = 30, message = "部门编码长度不能超过{max}个字符")
  20.     private String deptCode;
  21.  
  22.     /**
  23.      * 部门名称
  24.      */
  25.     @NotBlank(message = "部门名称不能为空")
  26.     @Size(min = 0, max = 30, message = "部门名称长度不能超过{max}个字符")
  27.     private String deptName;
  28.  
  29.     /**
  30.      * 部门类型 0机器人 1标件公司 2非标件公司
  31.      */
  32.     private String deptType;
  33.  
  34.     /**
  35.      * 显示顺序
  36.      */
  37.     @NotNull(message = "显示顺序不能为空")
  38.     private Integer orderNum;
  39.  
  40.     /**
  41.      * 负责人
  42.      */
  43.     private String leader;
  44.  
  45.     /**
  46.      * 联系电话
  47.      */
  48.     @Size(min = 0, max = 11, message = "联系电话长度不能超过{max}个字符")
  49.     private String phone;
  50.  
  51.     /**
  52.      * 邮箱
  53.      */
  54.     @Email(message = "邮箱格式不正确")
  55.     @Size(min = 0, max = 50, message = "邮箱长度不能超过{max}个字符")
  56.     private String email;
  57.  
  58.     /**
  59.      * 部门状态:0正常,1停用
  60.      */
  61.     private String status;
  62.  
  63.     /**
  64.      * 删除标志（0代表存在 2代表删除）
  65.      */
  66.     @TableLogic
  67.     private String delFlag;
  68.  
  69.     /**
  70.      * 祖级列表
  71.      */
  72.     private String ancestors;
  73. }

SysdeptPlus

  1. /**
  2.  * @author ChenSir
  3.  * @description
  4.  * @date 2023/10/26
  5.  **/
  6. @Data
  7. @NoArgsConstructor
  8. @AllArgsConstructor
  9. public class SysdeptPlus {
  10.     private SysDept sysDept;
  11.  
  12.     private List<SysDept> rows;
  13.  
  14.     private int total;
  15. }

serviceImpl

  1. @Override
  2.     public SysdeptPlus getTreePage(SysDept sysDept, PageQuery pageQuery) {
  3.  
  4.         int pageNum = pageQuery.getPageNum();
  5.         int pageSize = pageQuery.getPageSize();
  6.  
  7.         // 1、查询所有分类
  8.         QueryWrapper<SysDept> wrapper = Wrappers.query();
  9.         wrapper.eq(StrUtil.isNotBlank(sysDept.getStatus()), "status", sysDept.getStatus());
  10.         List<SysDept> sysDeptList = treePageMapper.selectList(wrapper);
  11.  
  12.         // 2、组装成父子树形结构 每条均为parentId=0 的根节点,其children包含其子节点
  13.         List<SysDept> testTrees = sysDeptList.stream().filter(testTree -> 0 == testTree.getParentId())
  14.                 .peek(testTree -> testTree.setChildren(createChildList(testTree, sysDeptList)))
  15.                 .collect(Collectors.toList());
  16.  
  17.         // 3、分页
  18.         List<SysDept> page = new ArrayList<>();
  19.         int start = (pageNum - 1) * pageSize;
  20.         for (int i = start; i < (start + pageSize > testTrees.size() ? testTrees.size() : start + pageSize); i++) {
  21.             page.add(testTrees.get(i));
  22.         }
  23.  
  24.         SysdeptPlus sysdeptPlus = new SysdeptPlus();
  25.         sysdeptPlus.setRows(page);
  26.         sysdeptPlus.setTotal(testTrees.size());
  27.         return sysdeptPlus;
  28.     }
  29.  
  30.  
  31.     /**
  32.      * @param testTree     父级
  33.      * @param testTreeList 对应的list
  34.      * @return
  35.      */
  36.     private static List<SysDept> createChildList(SysDept testTree, List<SysDept> testTreeList) {
  37.  
  38.         return testTreeList.stream().filter(model -> testTree.getDeptId().equals(model.getParentId()))
  39.                 .peek(model -> model.setChildren(createChildList(model, testTreeList)))
  40.                 .collect(Collectors.toList());
  41.     }

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