将json字符串转换为列表或映射

Question

我在服务器端获得了一个json字符串，如下所示

[     {"projectFileId":"8547",
       "projectId":"8235",
       "fileName":"1",
       "application":"Excel",
       "complexity":"NORMAL",
       "pageCount":"2",
       "targetLanguages":" ar-SA",
       "Id":"8547"
      },
      {"projectFileId":"8450",
       "projectId":"8235",
       "fileName":"Capacity Calculator.pptx",
       "application":"Powerpoint",
       "complexity":"NORMAL",
       "pageCount":"100",
       "targetLanguages":" ar-LB, ar-SA",
       "Id":"8450"
      }
]

我希望将此字符串转换为arraylist或map尽可能使我可以迭代它并获取字段值。

Answer 1

您可以使用GSON library。只需使用Gson#fromJson()方法将JSON字符串转换为Java Object。

示例代码：

BufferedReader reader = new BufferedReader(new FileReader(new File("json.txt")));
Gson gson = new Gson();
Type type = new TypeToken<ArrayList<Map<String, String>>>() {}.getType();
ArrayList<Map<String, String>> data = gson.fromJson(reader, type);

// convert back to JSON string from object
System.out.println(new GsonBuilder().setPrettyPrinting().create().toJson(data));

---

您可以创建一个POJO类，将其直接转换为POJO clas对象列表，以便轻松访问它。

示例代码：

class PojectDetail{
    private String projectFileId;
    private String projectId;
    private String fileName;
    private String application;
    private String complexity;
    private String pageCount;
    private String targetLanguages;
    private String Id;
    // getter & setter
}

Gson gson = new Gson();
Type type = new TypeToken<ArrayList<PojectDetail>>() {}.getType();
ArrayList<PojectDetail> data = gson.fromJson(reader, type);