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我正在尝试从 url 获取 json 字符串，当我使用这行代码时，我的方法返回一个空字符串值：

String jsonStr = getJsonStringFromURL(url);

这是我正在使用的方法：

public static String getJsonStringFromURL(String url)  {
    InputStream is = null; 
    String result = "";
    JSONObject jsonObject = null;

    try { 
        HttpClient httpclient = new DefaultHttpClient(); 
        HttpPost httppost = new HttpPost(url);
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent(); 
    }
    catch (Exception e) { 
        return null;
    }

    try { 
        BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) { 
            sb.append(line + "\n");
        }
        is.close();
        result = sb.toString();
    }
    catch(Exception e) { 
        return null;
    }
    return result;
}

我有一个 url 变量，当我将 url 复制并粘贴到浏览器中时，它会返回并显示一个 json 字符串。任何建议或帮助将不胜感激。

4

1 回答 1

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BufferReader问题是您在关闭时为结果赋值。这就是为什么你得到空值。

而不是分配result = sb.toString(); BufferReader在关闭它之前分配它之外。

   BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"), 8);
    StringBuilder sb = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) { 
        sb.append(line + "\n"); 
    }
    result = sb.toString();
    System.out.println(result);// It will print you the value
    is.close();

希望能帮助到你。

于 2013-03-27T16:20:02.437 回答