如何将JSON对象转为JSON数组并映射到自定义ReportResponse POJO

要完成从外部API响应到目标JSON结构的转换，我们需要修正现有代码中的映射逻辑，并正确封装结果。以下是分步实现方案：

1. 核心问题分析 #

现有代码的主要问题：

• 未将JSON对象的键映射到ReportResponse的name字段
• 返回的是原始API响应而非转换后的结果
• GET请求携带了不必要的请求体

2. 方案一：使用org.json库（保持原有技术栈） #

直接基于你当前使用的org.json库修改代码，实现正确映射：

import org.json.JSONArray;
import org.json.JSONObject;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;
import java.util.Iterator;

public String getReportList(String clientApiId) {
    try {
        final String url = "https://chapi.cloudhealthtech.com/olap_reports/custom?client_api_id=" + clientApiId;
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.AUTHORIZATION, "Bearer " + apiKey);
        headers.add(HttpHeaders.ACCEPT, "application/json");
        
        // GET请求无需请求体，传入null即可
        HttpEntity<String> requestEntity = new HttpEntity<>(null, headers);
        ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity, String.class);
        
        JSONObject originalObj = new JSONObject(responseEntity.getBody());
        JSONObject linksObj = originalObj.getJSONObject("links");
        
        Iterator<String> keyIterator = linksObj.keys();
        JSONArray responseArray = new JSONArray();
        
        while (keyIterator.hasNext()) {
            String reportName = keyIterator.next();
            JSONObject hrefObj = linksObj.getJSONObject(reportName);
            
            // 映射到ReportResponse POJO
            ReportResponse report = new ReportResponse();
            report.setName(reportName);
            report.setHref(hrefObj.getString("href"));
            
            // 转换为JSON对象并加入数组
            JSONObject reportJson = new JSONObject();
            reportJson.put("name", report.getName());
            reportJson.put("href", report.getHref());
            responseArray.put(reportJson);
        }
        
        // 封装最终响应结构
        JSONObject finalResponse = new JSONObject();
        finalResponse.put("response", responseArray);
        
        return finalResponse.toString();
        
    } catch (Exception e) {
        e.printStackTrace();
        // 返回标准化错误响应
        return new JSONObject().put("error", "处理报告列表失败：" + e.getMessage()).toString();
    }
}

3. 方案二：使用Jackson（Spring推荐方式） #

利用Spring默认的Jackson库实现更简洁的POJO映射，同时创建响应包装类：

3.1 创建响应包装类 #

import java.util.List;

public class ReportListResponse {
    private List<ReportResponse> response;

    public ReportListResponse() {}

    public ReportListResponse(List<ReportResponse> response) {
        this.response = response;
    }

    // Getter和Setter
    public List<ReportResponse> getResponse() {
        return response;
    }

    public void setResponse(List<ReportResponse> response) {
        this.response = response;
    }
}

3.2 修改业务方法 #

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.type.TypeReference;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public ReportListResponse getReportList(String clientApiId) {
    ObjectMapper objectMapper = new ObjectMapper();
    try {
        final String url = "https://chapi.cloudhealthtech.com/olap_reports/custom?client_api_id=" + clientApiId;
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.AUTHORIZATION, "Bearer " + apiKey);
        headers.add(HttpHeaders.ACCEPT, "application/json");
        
        HttpEntity<String> requestEntity = new HttpEntity<>(null, headers);
        ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity, String.class);
        
        // 解析响应并提取links节点
        JsonNode rootNode = objectMapper.readTree(responseEntity.getBody());
        JsonNode linksNode = rootNode.get("links");
        
        // 转换为键值对映射
        Map<String, JsonNode> linksMap = objectMapper.convertValue(linksNode, new TypeReference<>() {});
        
        // 映射到ReportResponse列表
        List<ReportResponse> reportList = new ArrayList<>();
        for (Map.Entry<String, JsonNode> entry : linksMap.entrySet()) {
            ReportResponse report = new ReportResponse();
            report.setName(entry.getKey());
            report.setHref(entry.getValue().get("href").asText());
            reportList.add(report);
        }
        
        return new ReportListResponse(reportList);
        
    } catch (Exception e) {
        e.printStackTrace();
        // 可自定义错误响应类返回
        throw new RuntimeException("获取报告列表失败：" + e.getMessage());
    }
}

注：如果该方法是@RestController的接口方法，直接返回ReportListResponse即可，Spring会自动将其序列化为目标JSON结构。

4. 关键改进点 #

• 正确将JSON对象的键映射到ReportResponse的name字段
• 移除GET请求中不必要的请求体
• 封装结果为{"response": [...]}的目标结构
• 增加异常处理，返回标准化错误响应

内容的提问来源于stack exchange，提问作者rsharma