Question

我正在打开一个HttpURLConnection并使用POST方法，我发送一个JSON请求，我构建另一个类。 JSON的结构正确，因为我已经在调试时验证了它。尝试读取服务器给出的输出响应时抛出异常。这是给出的错误

java.io.IOException: Server returned HTTP response code: 400 for URL:

但是，当我手动尝试使用Url方法Chrome扩展程序从网络浏览器输入POST时。我可以查看响应，一切正常。所以我确信它与下面的代码有关，我在那里进行连接和读/写。

    URL obj = new URL(url);

    HttpURLConnection connection = (HttpURLConnection) obj.openConnection();
    //add request header
    connection.setRequestMethod("POST");
    connection.setRequestProperty("Content-Type", "application/json");
    //mapping objects to json
    BatchRequest requestParameters = new BatchRequest(o,d);

    ObjectMapper mapper = new ObjectMapper();

    String json = mapper.writeValueAsString(requestParameters);

    connection.setDoOutput(true);
    DataOutputStream os = new DataOutputStream(connection.getOutputStream());

    os.writeBytes(json);
    os.flush();
    os.close();
         // this is where the program throws the exception  
    BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));

    String inputLine;
    StringBuilder response = new StringBuilder();

    while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
    }
    in.close();

URL和JSON请求都是正确的，因为它们在我尝试通过浏览器进行手动连接时起作用。

Answer 1

不需要DataOutputStream。只是：

OutputStream os = con.getOutputStream();

Java - 从HttpURLConnection读取POST，抛出响应代码400

1 个答案: