如何使用gson解析特定的對象數組？

Question

我想在JSON中使用Gson庫獲取JSON對象數組，但在這裏我遇到了一個問題，如何訪問嵌套JSON數組中的特定JSON數組。這是我正在嘗試：

我的模型類：

public class ComposeSMSList { 

@SerializedName("userMessages") 
@Expose 
private List<UserMessage> userMessages = null; 
@SerializedName("userPhoneBooks") 
@Expose 
private List<UserPhoneBook> userPhoneBooks = null; 
@SerializedName("usersSendorIds") 
@Expose 
private List<UsersSendorId> usersSendorIds = null; 
@SerializedName("userTemplates") 
@Expose 
private List<UserTemplate> userTemplates = null; 

public List<UserMessage> getUserMessages() { 
    return userMessages; 
} 

public void setUserMessages(List<UserMessage> userMessages) { 
    this.userMessages = userMessages; 
} 

public List<UserPhoneBook> getUserPhoneBooks() { 
    return userPhoneBooks; 
} 

public void setUserPhoneBooks(List<UserPhoneBook> userPhoneBooks) { 
    this.userPhoneBooks = userPhoneBooks; 
} 

public List<UsersSendorId> getUsersSendorIds() { 
    return usersSendorIds; 
} 

public void setUsersSendorIds(List<UsersSendorId> usersSendorIds) { 
    this.usersSendorIds = usersSendorIds; 
} 

public List<UserTemplate> getUserTemplates() { 
    return userTemplates; 
} 

public void setUserTemplates(List<UserTemplate> userTemplates) { 
    this.userTemplates = userTemplates; 
} 

} 

現在我想從父類訪問用戶的電話簿類。
有沒有優雅的方式來做到這一點？

我的代碼：

Gson mGson=new Gson(); 
List<ComposeModel> posts=Arrays.asList(mGson.fromJson(response.toString(),ComposeModel.class)); 

for (int i=0;i<posts.size();i++){ 
    ComposeModel object = new ComposeModel(posts.get(i).getComposeSMSList().getUserMessages().get(i).getId(),posts.get(i).getComposeSMSList().getUserMessages().get(i).getMessage()); 
    global.add(object); 
} 
mUserMsgAdpater=new UserMsgAdpater(mContext,global); 
mRecyclerView.setAdapter(mUserMsgAdpater); 

Answer 1

你是什麼ComposeModel類？無論如何，你插入評論的Json是不完整的。我認爲是這樣的：

ComposeSMS.json

{ 
    "userMessages":[ 
    { 
     "id":1, 
     "message":"this is a message" 
    } 
    ], 
    "userPhoneBooks":[ 
    { 
     "id":1, 
     "phonebookGroupname":"ISKON", 
     "nrOfContacts":2924 
    } 
    ], 
    "usersSendorIds":[ 
    { 
     "id":1 
    } 
    ], 
    "userTemplates":[ 
    { 
     "id":1, 
     "templateName":"aTemplate" 
    } 
    ] 
} 

如果您有ComposeSMSList類：

public class ComposeSMSList { 

    private List<UserMessage> userMessages = null; 
    private List<UserPhoneBook> userPhoneBooks = null; 
    private List<UsersSendorId> usersSendorIds = null; 
    private List<UserTemplate> userTemplates = null; 

    public List<UserMessage> getUserMessages() { 
     return userMessages; 
    } 

    public void setUserMessages(List<UserMessage> userMessages) { 
     this.userMessages = userMessages; 
    } 

    public List<UserPhoneBook> getUserPhoneBooks() { 
     return userPhoneBooks; 
    } 

    public void setUserPhoneBooks(List<UserPhoneBook> userPhoneBooks) { 
     this.userPhoneBooks = userPhoneBooks; 
    } 

    public List<UsersSendorId> getUsersSendorIds() { 
     return usersSendorIds; 
    } 

    public void setUsersSendorIds(List<UsersSendorId> usersSendorIds) { 
     this.usersSendorIds = usersSendorIds; 
    } 

    public List<UserTemplate> getUserTemplates() { 
     return userTemplates; 
    } 

    public void setUserTemplates(List<UserTemplate> userTemplates) { 
     this.userTemplates = userTemplates; 
    } 
} 

你可以反序列化JSON的這樣：

 Gson gson = new Gson(); 
     String filename="/pathTo.../composeSMS.json"; 
     JsonReader reader = new JsonReader(new FileReader(filename)); 
     ComposeSMSList composeSMSList= gson.fromJson(reader, ComposeSMSList.class); 
     System.out.println("composeSMSList: " + gson.toJson(composeSMSList)); 

在你的問題中，你要求訪問UserPhoneBook，但是在你的代碼中你可以用UserMessage進行嘗試。

無論如何，你可以以這種方式訪問​​：

 List<UserPhoneBook> userPhoneBooks= composeSMSList.getUserPhoneBooks(); 
     for(UserPhoneBook upb: userPhoneBooks) 
     { 
      System.out.println("UserPhoneBook id: " + upb.getId()); 
      System.out.println("UserPhoneBook nrOfContacts: " +upb.getNrOfContacts()); 
      System.out.println("UserPhoneBook phonebookGroupname: " +upb.getPhonebookGroupname()); 
     }