SpringBoot读取本地json文件，java递归方法，根据父id返回子集列表

红太狼 2021-09-02 08:17 402阅读 0赞

## java递归方法，根据父id返回子集列表 ##

**解析之后的json结构**

{
        "code": 0,
        "message": "success",
        "tipMsg": null,
        "result": [
            {
                "id": "1030101",
                "name": "教学素材01"
            },
            {
                "id": "1030102",
                "name": "教学素材02"
            }
        ]
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3ODgwOTY4_size_16_color_FFFFFF_t_70_pic_center]  
**java代码实现**

package com.necibook.resource.service.impl;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONArray;
    import com.alibaba.fastjson.JSONObject;
    import com.necibook.resource.common.enums.ResourceErrorCode;
    import com.necibook.resource.exception.ResourceException;
    import com.necibook.resource.model.qo.ResourceTypeQo;
    import com.necibook.resource.model.vo.ResourceTypeVo;
    import com.necibook.resource.service.ResourceTypeService;
    import org.springframework.stereotype.Service;
    
    import java.io.*;
    import java.nio.charset.StandardCharsets;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Objects;
    
    
    @Service
    public class ResourceTypeServiceImpl implements ResourceTypeService {
    
        @Override
        public List<ResourceTypeVo> getResourceTypes(ResourceTypeQo resourceTypeQo) {
            String path = Objects.requireNonNull(ResourceTypeServiceImpl.class.getClassLoader().getResource("resource-type.json")).getPath();
            String s = readJsonFile(path);
            JSONObject jobj = JSON.parseObject(s);
            //构建JSONArray数组
            JSONArray movies = jobj.getJSONArray("RECORDS");
            List<ResourceTypeVo> resourceTypeVos = new ArrayList<>();
            List<ResourceTypeVo> resourceTypeVoList = nextList(resourceTypeQo.getId(), movies, resourceTypeVos);
            if (resourceTypeVoList.size() > 0) {
                return resourceTypeVoList;
            } else {
                throw new ResourceException(ResourceErrorCode.RESOURCE_TYPE_NOT_FOUND.getMsg(), ResourceErrorCode.RESOURCE_TYPE_NOT_FOUND.getCode());
            }
        }
    
        //读取json文件
        private String readJsonFile(String fileName) {
            String jsonStr = "";
            try {
                File jsonFile = new File(fileName);
                FileReader fileReader = new FileReader(jsonFile);
                Reader reader = new InputStreamReader(new FileInputStream(jsonFile), StandardCharsets.UTF_8);
                int ch = 0;
                StringBuilder sb = new StringBuilder();
                while ((ch = reader.read()) != -1) {
                    sb.append((char) ch);
                }
                fileReader.close();
                reader.close();
                jsonStr = sb.toString();
                return jsonStr;
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }
    
        private List<ResourceTypeVo> nextList(String id, JSONArray movies, List<ResourceTypeVo> resourceTypeVos) {
            for (Object movie : movies) {
                JSONObject object = (JSONObject) movie;
                String aimsId = (String) object.get("id");
                String name = (String) object.get("name");
                JSONArray subLit = object.getJSONArray("subLit");
                if (subLit != null && subLit.size() > 0) {
                    if (id.equals(aimsId)) {
                        for (Object sub : subLit) {
                            JSONObject obj = (JSONObject) sub;
                            String idNext = (String) obj.get("id");
                            String nameNext = (String) obj.get("name");
                            ResourceTypeVo resourceTypeVo = new ResourceTypeVo();
                            resourceTypeVo.setId(idNext);
                            resourceTypeVo.setName(nameNext);
                            resourceTypeVos.add(resourceTypeVo);
                        }
                    } else {
                        nextList(id, subLit, resourceTypeVos);
                    }
                } else {
                    System.out.println(name+":没查询到当前子类");
                }
            }
            return resourceTypeVos;
        }
    }

**本地的json文件格式**

{
      "RECORDS": [
        {
          "id": "101",
          "name": "资源分类",
          "subLit": [
            {
              "id": "10101",
              "name": "热门学习方向"
            }
          ]
        },
        {
          "id": "102",
          "name": "其他分类方式",
          "subLit": [
            {
              "id": "10201",
              "name": "院校专业分类"
            },
            {
              "id": "10202",
              "name": "院校专题"
            }
          ]
        },{
          "id": "103",
          "name": "资源类型",
          "subLit": [
            {
              "id": "10301",
              "name": "教学素材",
              "subLit": [
                {
                  "id": "1030101",
                  "name": "教学素材01"
                },
                {
                  "id": "1030102",
                  "name": "教学素材02"
                }
              ]
            },
            {
              "id": "10302",
              "name": "实训案例"
            },
            {
              "id": "10303",
              "name": "试卷"
            },
            {
              "id": "10304",
              "name": "其他"
            }
          ]
        }
      ]
    }

package com.necibook.resource.model.vo;
    
    import lombok.Data;
    
    /**
     * 获取资源类型
     *
     * @author : lbx
     */
    
    @Data
    public class ResourceTypeVo {
        /**
         * id
         */
        private String id;
        /**
         * 名称
         */
        private String name;
    
    }

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