JSON解析與庫GSON在Java中

Question

我試圖解析此JSON通過我的客戶的API捕獲：

[ 
    { 
    "pagination": { 
     "page": 7, 
     "total_pages": 11, 
     "entries": 100, 
     "total_entries": 1007 
    }, 
    "logical_numbers": [ 
     { 
     "logical_number": { 
      "id": 50095, 
      "number": "524103650", 
      "app_version_ids": [ 
      1427, 
      1230, 
      847 
      ], 
      "created_by": 1510, 
      "created_via": "interface", 
      "group_id": 526, 
      "created_at": "2016-03-21T15:54:30.670-03:00", 
      "updated_at": "2016-03-21T15:54:30.682-03:00" 
     } 
     }, 
     { 
     "logical_number": { 
      "id": 44593, 
      "number": "524103627", 
      "app_version_ids": [ 
      1427, 
      1230, 
      847 
      ], 
      "created_by": 1510, 
      "created_via": "interface", 
      "group_id": 526, 
      "created_at": "2016-02-26T10:02:20.561-03:00", 
      "updated_at": "2016-02-26T10:02:20.608-03:00" 
     } 
     } 
    ] 
    } 
] 

下面是我對這項工作創建的類：

import java.io.FileReader; 
import java.util.ArrayList; 
import com.google.gson.Gson; 

public class Test { 
    public static void main(String[] args) { 
     Gson gson = new Gson(); 
     Pagination[] pagination = gson.fromJson(new FileReader("input1.json"), Pagination[].class); 
     System.out.println(gson.toJson(pagination)); 
    } 
} 

class Pagination { 
    Long page; 
    Long total_pages; 
    Long entries; 
    Long total_entries; 
    ArrayList<LogicalNumbers> logicals; 
} 

class LogicalNumbers { 
    int id; 
    String number; 
    ArrayList<String> app_version_ids = new ArrayList<>(); 
    String created_by; 
    String created_via; 
    String group_id; 
    String created_at; 
    String updated_at; 
} 

當我運行這段代碼，我得到以下結果：

[{}]

我在解析中沒有成功。有誰能夠幫助我？

謝謝。

Answer 1

探索JSON後，我發現空deseralization的原因...... 你有兩個小問題... 一日一： 您的JSON實際上是一個對象數組，其中包含一個分頁 對象和一個邏輯數字陣列

第二：將JSON模式的POJO描述不正確..

一段時間後，我發現了一個解決方案：

嘗試：

class Foo { 
private Pagination pagination; 
private List<LogicalNumbers> logical_numbers; 
} 

class Pagination { 
Long page; 
Long total_pages; 
Long entries; 
Long total_entries; 
} 

class LogicalNumbers { 
Ln logical_number; 

} 

class Ln { 
int id; 
String number; 
List<String> app_version_ids = new ArrayList<>(); 
String created_by; 
String created_via; 
String group_id; 
String created_at; 
String updated_at; 
} 

然後

public static void main(String[] args) { 
    Gson gson = new Gson(); 
    Foo[] pagination = gson.fromJson(new FileReader("input1.json"), Foo[].class); 
// Pagination[] pagination = gson.fromJson(new FileReader("input1.json"), Pagination[].class); 
    System.out.println(gson.toJson(pagination)); 
}