Java應用程序模擬向Servlet發送POST請求

在某些情況下，需要用Java applicatioin來模擬form，向服務器(本文以servlet為例)發送http post請求，包括提交表單域中的數據以及上傳文件。如果僅僅是傳遞form中的數據，而不包含上傳文件，那是很簡單的，比如Java application可以這麼寫：

package com.pat.postrequestemulator;

importjava.io.BufferedReader;

importjava.io.InputStream;

importjava.io.InputStreamReader;

importjava.io.OutputStreamWriter;

importjava.net.HttpURLConnection;

importjava.net.URL;

public classPostRequestEmulator

{

public static void main(String[] args)throws Exception

{

// 服務地址

URL url = newURL("http://127.0.0.1:8080/test/upload");

// 設定連接的相關參數

HttpURLConnection connection= (HttpURLConnection) url.openConnection();

connection.setDoOutput(true);

connection.setRequestMethod("POST");

OutputStreamWriter out = newOutputStreamWriter(connection.getOutputStream(), "UTF-8");

// 向服務端發送key = value對

out.write("username=kevin&password=pass");

out.flush();

out.close();

// 獲取服務端的反饋

String strLine="";

String strResponse ="";

InputStream in =connection.getInputStream();

BufferedReader reader = newBufferedReader(new InputStreamReader(in));

while((strLine =reader.readLine()) != null)

{

strResponse +=strLine +"\n";

}

System.out.print(strResponse);

}

}

服務端的servlet可以這麼寫：

packagecom.pat.handlinghttprequestservlet;

importjava.io.IOException;

importjava.io.PrintWriter;

importjavax.servlet.ServletException;

importjavax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

public classHandlingHttpRequestServlet extends HttpServlet

{

private static final longserialVersionUID = 1L;

@Override

protected void doGet(HttpServletRequestreq, HttpServletResponse resp)

throws ServletException, IOException

{

super.doGet(req, resp);

}

@Override

protected voiddoPost(HttpServletRequest req, HttpServletResponse resp)

throwsServletException, IOException

{

String username =req.getParameter("username"); //獲取username所對應的value

String password =req.getParameter("password"); //獲取password所對應的value

System.out.println("Thereceived username and password is: " + username + "/" +password);

// 向請求端發回反饋信息

PrintWriter out =resp.getWriter();

out.print("OK");

out.flush();

out.close();

super.doPost(req, resp);

}

}

一切看起來都不復雜。但是如果要模擬的表單，除了要向服務器傳遞如上面的“key = value”這樣的普通信息，同時還要上傳文件，事情就復雜得多。