因為項目需要，頁面上需要樹形結(jié)構(gòu)的數(shù)據(jù)進行展示（類似下圖這樣），因此需要后端返回相應格式的數(shù)據(jù)。
不說廢話，直接開干！！！
我這里用的是springboot+mybatis-plus+mysql，示例的接口是查詢一級權(quán)限以及二級權(quán)限、三級權(quán)限整個權(quán)限樹…
下面是導入的maven依賴
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<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency><!--數(shù)據(jù)庫連接--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.21</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!--mybatis增強工具--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.4.0</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>5.0.6</version> </dependency> |
下面是實體類Permission
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@Datapublic class Permission implements Serializable { @TableId private String permissionId; @NotNull(message = "權(quán)限名稱不能為空") private String permissionName; /** * 權(quán)限標識 */ @NotNull(message = "權(quán)限標識不能為空") private String permissionCode; /** * 父菜單ID，如果是-1就表示是一級權(quán)限菜單。 */ @NotBlank(message = "父菜單ID不能為空") private String parentId; /** * 前端URL訪問接口路徑 */ private String path; /** * 排序值 */ private Integer sort; /** * 創(chuàng)建時間 */ private LocalDateTime createTime; /** * 更新時間 */ private LocalDateTime updateTime; /** * 0--正常 1--刪除 */ private String delFlag; public Permission() { this.permissionId = IdUtil.simpleUUID(); } |
樹形結(jié)點類
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@Datapublic class TreeNode { protected String id; protected String parentId; protected List<TreeNode> children = new ArrayList<TreeNode>(); protected boolean hasChildren; public void addTreeNode(TreeNode node){ children.add(node); }} |
樹形結(jié)點詳細信息類
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@Data@EqualsAndHashCode(callSuper = true)public class PermissionTree extends TreeNode implements Serializable { private String permissionName; private String permissionCode; private String path; private Integer sort; private String label; private boolean hasChildren; public PermissionTree() { }} |
構(gòu)建樹形結(jié)點工具類（關(guān)鍵），在這里我用@UtilityClass注解就表示這個類中的方法都是靜態(tài)方法：
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@UtilityClasspublic class TreeUtil { public <T extends TreeNode> List<T> build(List<T> treeNodes, String root) { List<T> trees = new ArrayList<>(); for (T treeNode : treeNodes) { if (root.equals(treeNode.getParentId())) { trees.add(treeNode); } for (T node : treeNodes) { if (node.getParentId().equals(treeNode.getId())) { treeNode.addTreeNode(node); treeNode.setHasChildren(true); } } } return trees; } /** * 通過permission創(chuàng)建樹形節(jié)點 * * @param permissionList * @param root * @return */ public List<PermissionTree> buildTree(List<Permission> permissionList, String root) { System.out.println(Arrays.toString(permissionList.toArray())); List<PermissionTree> treeNodeList = new ArrayList<>(); PermissionTree treeNode = null; for (Permission permission : permissionList) { treeNode = new PermissionTree(); treeNode.setId(permission.getPermissionId()); treeNode.setPermissionName(permission.getPermissionName()); treeNode.setPath(permission.getPath()); treeNode.setSort(permission.getSort()); treeNode.setParentId(permission.getParentId()); treeNode.setLabel(permission.getPermissionName()); treeNode.setHasChildren(false); treeNodeList.add(treeNode); } return TreeUtil.build(treeNodeList, root); } } |
響應消息主體類
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/** * 響應信息主體 * * @param <T> */@ToString@NoArgsConstructor@AllArgsConstructor@Accessors(chain = true)public class R<T> implements Serializable { private static final long serialVersionUID = 1L; private int code; private String msg; private T data; public int getCode() { return code; } public void setCode(int code) { this.code = code; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } public T getData() { return data; } public void setData(T data) { this.data = data; } public static <T> R<T> ok() { return restResult(null, CommonConstants.SUCCESS, CommonConstants.MSG_SUCCESS); } public static <T> R<T> ok(T data) { return restResult(data, CommonConstants.SUCCESS, CommonConstants.MSG_SUCCESS); } public static <T> R<T> ok(T data, String msg) { return restResult(data, CommonConstants.SUCCESS, msg); } public static <T> R<T> failed() { return restResult(null, CommonConstants.FAIL, null); } public static <T> R<T> failed(String msg) { return restResult(null, CommonConstants.FAIL, msg); } public static <T> R<T> failed(T data) { return restResult(data, CommonConstants.FAIL, null); } public static <T> R<T> failed(T data, String msg) { return restResult(data, CommonConstants.FAIL, msg); } private static <T> R<T> restResult(T data, int code, String msg) { R<T> apiResult = new R<>(); apiResult.setCode(code); apiResult.setData(data); apiResult.setMsg(msg); return apiResult; }} |
數(shù)據(jù)查詢接口mapper類
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@Mapperpublic interface PermissionMapper extends BaseMapper<Permission>{ } |
數(shù)據(jù)邏輯處理業(yè)務接口
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public interface PermissionService extends IService<Permission> { /** * 構(gòu)建權(quán)限樹 * * @param lazy * @param parentId * @return */ List<PermissionTree> treePermission(boolean lazy, String parentId);} |
數(shù)據(jù)邏輯處理業(yè)務接口實現(xiàn)類
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@Servicepublic class PermissionServiceImpl extends ServiceImpl<PermissionMapper, Permission> implements PermissionService {/** * 構(gòu)建權(quán)限樹：1、不是懶加載情況，查詢?nèi)?/code> * 2、是懶加載，根據(jù)parentId查詢 * * @param lazy * @param parentId * @return */ @Override public List<PermissionTree> treePermission(boolean lazy, String parentId) { if (!lazy) { return TreeUtil.buildTree( baseMapper.selectList(Wrappers.<Permission>lambdaQuery().orderByAsc(Permission::getSort)), CommonConstants.PERMISSION_ROOT_ID); } String parent = parentId == null ? CommonConstants.PERMISSION_ROOT_ID : parentId; return TreeUtil.buildTree( baseMapper.selectList(Wrappers.<Permission>lambdaQuery().eq(Permission::getParentId, parent).orderByAsc(Permission::getSort)), parent ); }} |
查詢權(quán)限樹請求接口類
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@RestController@RequestMapping("/permission")public class PermissionController { @Autowire private PermissionService permissionService; /** * 查詢權(quán)限列表，并以樹狀結(jié)構(gòu)顯示 * * @param lazy 懶加載: false時, parentId這個參數(shù)失效, 加載所有的權(quán)限; true時, 根據(jù)parentId加載 * @param parentId * @return */ @RequestMapping(value = "/getTree", method = RequestMethod.GET) public R getTree(boolean lazy, String parentId) { return R.ok(permissionService.treePermission(lazy, parentId)); } } |
表中測試數(shù)據(jù)如下（注意它的parent_id）
測試一：不是懶加載，查詢整個權(quán)限樹。 結(jié)果如下。
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{ "code": 0, "msg": "SUCCESS", "data": [ { "id": "1", "parentId": "-1", "children": [ { "id": "2", "parentId": "1", "children": [ { "id": "3", "parentId": "2", "children": [], "hasChildren": false, "permissionName": "update", "permissionCode": null, "path": null, "sort": 3, "label": "update", "owned": false }, { "id": "4", "parentId": "2", "children": [], "hasChildren": false, "permissionName": "insert_role", "permissionCode": null, "path": null, "sort": 4, "label": "insert_role", "owned": false } ], "hasChildren": true, "permissionName": "delete", "permissionCode": null, "path": null, "sort": 2, "label": "delete", "owned": false } ], "hasChildren": true, "permissionName": "add", "permissionCode": null, "path": null, "sort": 1, "label": "add", "owned": false }, { "id": "5", "parentId": "-1", "children": [], "hasChildren": false, "permissionName": "role:saveRole", "permissionCode": null, "path": "/role/saveRole", "sort": 5, "label": "role:saveRole", "owned": false } ]} |
測試二：是懶加載，根據(jù)parent_id查詢當前分支。 結(jié)果如下。
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{ "code": 0, "msg": "SUCCESS", "data": [ { "id": "3", "parentId": "2", "children": [], "hasChildren": false, "permissionName": "update", "permissionCode": null, "path": null, "sort": 3, "label": "update", "owned": false }, { "id": "4", "parentId": "2", "children": [], "hasChildren": false, "permissionName": "insert_role", "permissionCode": null, "path": null, "sort": 4, "label": "insert_role", "owned": false } ]} |
到此這篇關(guān)于springboot構(gòu)造樹形結(jié)構(gòu)數(shù)據(jù)并查詢的方法的文章就介紹到這了,更多相關(guān)springboot 樹形結(jié)構(gòu)并查詢內(nèi)容請搜索服務器之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持服務器之家！
原文鏈接：https://blog.csdn.net/to10086/article/details/109730685
