java - 处理来自 httpresponse android 的 json 的最佳方法

Question

我使用httpclient来调用用django编写的restapi。它返回了 json 输出。我的 httpresponse 变量存储了它，然后将响应转换为字符串，然后转换为 json 对象，我认为虽然它正在工作，但它很长。我对java真的很陌生，任何人都可以告诉我，下面代码的最佳替代逻辑是什么

public void onClick(View v) {
    // TODO Auto-generated method stub

    HttpClient httpclient = new DefaultHttpClient();
    HttpGet httppost = new HttpGet("http://10.0.2.2:8000/api/ca/entry/?
            format=json&username=pragya");
    try {
        // Add your data
        //List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
        //nameValuePairs.add(new BasicNameValuePair("username", un.getText().toString()));
        //nameValuePairs.add(new BasicNameValuePair("username", pw.getText().toString()));
        //httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));


        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        InputStream is = entity.getContent();
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append((line + "\n"));
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        try {
            JSONObject jsonObject = new JSONObject(sb.toString());
            JSONObject meta = jsonObject.getJSONObject("meta");  
            String limit = meta.getString("limit");  
            Toast.makeText(HelloWorldActivity.this, limit, Toast.LENGTH_SHORT).show();
            JSONArray array = jsonObject.getJSONArray("objects");

            String key = array.getJSONObject(0).getString("api_key");
            String uname = array.getJSONObject(0).getString("username");
            Toast.makeText(HelloWorldActivity.this, uname + " " + key,
            Toast.LENGTH_SHORT).show();

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
        //Toast.makeText(HelloWorldActivity.this, sb.toString(), Toast.LENGTH_SHORT).show();
    } catch (ClientProtocolException e) {
        Toast.makeText(HelloWorldActivity.this, e.toString(), Toast.LENGTH_SHORT).show();

        // TODO Auto-generated catch block
    } catch (IOException e) {
        // TODO Auto-generated catch block
        Toast.makeText(HelloWorldActivity.this, e.toString(), Toast.LENGTH_SHORT).show();
    }   
}
});

json如下

{"meta": {"limit": 20, "next": null, "offset": 0, "previous": null, "total_count": 1}, "objects": [{"api_key": "c87391754b522d0c83b2c8b5e4c8cfd614559632deee70fdf1b48d470307e40e", "homeAddress": "kathmandu", "resource_uri": "/api/ca/entry/1/", "username": "sumit"}]}

Answer 1

使用Gson来自 google 的库，它非常适合此类任务。

您需要做的就是定义一个新类，其中包含具有 json 对象中的键名称的字段，然后使用 Gson 将 Json 字符串直接解析到对象中，反之亦然。

例如:

Json 如下所示:"limit": 20、"next": null、"offset": 0、"previous": null、"total_count": 1。

Java 类将是:

public class MyClass {
    private int limit;
    private int next;
    private int offset;
    private int previous;
    private int total_count;

public int getLimit() {
    return limit;
}
public void setLimit(int limit) {
    this.limit = limit;
}
public int getNext() {
    return next;
}
public void setNext(int next) {
    this.next = next;
}
public int getOffset() {
    return offset;
}
public void setOffset(int offset) {
    this.offset = offset;
}
public int getPrevious() {
    return previous;
}
public void setPrevious(int previous) {
    this.previous = previous;
}
public int getTotal_count() {
    return total_count;
}
public void setTotal_count(int total_count) {
    this.total_count = total_count;
}
}

并使用这样的 Gson 代码:

 Gson gson = new Gson(); // Or use new GsonBuilder().create();
 MyClass myClass = gson.fromJson(json, MyClass.class); // deserializes json into MyClass 

请注意，类字段的名称必须与 json 字符串中的键名称完全匹配。