Question

我从GWT-Client提交JSON数据并将其传递给我的GWT-Server。我想将数据重新提交到另一台服务器，并希望从另一台服务器响应GWT-Client。

我只是不知道我该怎么做。我尝试了以下代码，但没有工作。

我的代码是：

@Override
protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    System.out.println("POST");

    StringBuffer jb = new StringBuffer();
    URL oracle = new URL("http://www.google.com");

    HttpURLConnection connection = null;
    connection = (HttpURLConnection) oracle.openConnection();
    connection.setRequestMethod("GET");
    connection.setDoOutput(true);
    connection.setDoInput(true);
    request.getInputStream();

    OutputStream wr = connection.getOutputStream();

    InputStream in = request.getInputStream();
    byte[] buffer = new byte[512];
    int read = in.read(buffer, 0, buffer.length);
    while (read >= 0) {
        wr.write(buffer, 0, read);
        read = in.read(buffer, 0, buffer.length);
    }

    wr.flush();
    wr.close();

    BufferedReader in1 = new BufferedReader(new InputStreamReader(
            connection.getInputStream()));
    String inputLine;
    while ((inputLine = in1.readLine()) != null) {
        jb.append(inputLine);
    }
    response.setContentType("text/html");
    // Get the printwriter object from response to write the required json
    // object to the output stream
    PrintWriter out = response.getWriter();
    // Assuming your json object is **jsonObject**, perform the following,
    // it will return your json object
    out.print(jb.toString());
    out.flush();
    in1.close();
}

请帮帮我。

Answer 1

在阅读回复

之前，您必须将请求发送到其他服务器

URL oracle = new URL("http://www.anotherserver.com/");

HttpURLConnection connection = null;
connection = (HttpURLConnection) oracle.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);

OutputStream wr = connection.getOutputStream ();

InputStream in = request.getInputStream();
byte[] buffer = new byte[512]; 
int read = in.read(buffer,0, buffer.length);
while (read >= 0) {
   wr.write(buffer,0, read);
   read = in.read(buffer,0,buffer.length);
}

wr.flush ();
wr.close ();


BufferedReader in = new BufferedReader(new InputStreamReader(
        connection.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
    jb.append(inputLine);
}

另见Using java.net.URLConnection to fire and handle HTTP requests

Answer 2

此外，您可以使用Apache httpclient，实现您的要求非常简单，例如：

public static void main(String[] args) {
    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost("http://www.anotherserver.com/");
    try {
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
        nameValuePairs.add(new BasicNameValuePair("key",
                "value"));
        post.setEntity(new UrlEncodedFormEntity(nameValuePairs));

        HttpResponse response = client.execute(post);
        BufferedReader rd = new BufferedReader(new InputStreamReader(
                response.getEntity().getContent()));
        String line = "";
        while ((line = rd.readLine()) != null) {
            System.out.println(line);
        }

    } catch (IOException e) {
        e.printStackTrace();
    }
}

将POST数据从一个servlet调用到另一个服务器

2 个答案: