转自：http://blog.csdn.net/wulianghuan/article/details/8626551
我们知道通过Get方式提交的数据是作为Url地址的一部分进行提交，而且对字节数的长度也有限制，与Get方式类似，http-post参数也是被URL编码的，然而它的变量名和变量值不作为URL的一部分被传送，而是放在实际的HTTP请求消息内部被传送。
可以通过如下的代码设置POST提交方式参数：
- HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
- urlConnection.setConnectTimeout(3000);
- urlConnection.setRequestMethod("POST"); //以post请求方式提交
- urlConnection.setDoInput(true); //读取数据
- urlConnection.setDoOutput(true); //向服务器写数据
- //获取上传信息的大小和长度
- byte[] myData = stringBuilder.toString().getBytes();
- //设置请求体的类型是文本类型,表示当前提交的是文本数据
- urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
- urlConnection.setRequestProperty("Content-Length", String.valueOf(myData.length));
这里使用一个案例来看一下如何使用post方式提交数据到服务器：
首先我们创建一个java project，只要创建一个类就行，我们创建一个HttpUtils.java类，
【代码如下】：
我们再创建一个服务端工程，一个web project，这里创建一个myhttp的工程，先给它创建一个servlet，用来接收参数访问。
创建的servlet配置如下：
- <servlet>
- <description>This is the description of my J2EE component</description>
- <display-name>This is the display name of my J2EE component</display-name>
- <servlet-name>LoginAction</servlet-name>
- <servlet-class>com.login.manager.LoginAction</servlet-class>
- </servlet>
- <servlet-mapping>
- <servlet-name>LoginAction</servlet-name>
- <url-pattern>/servlet/LoginAction</url-pattern>
- </servlet-mapping>
建立的LoginAction.java类继承HttpServlet:
- package com.login.manager;
- import java.io.IOException;
- import java.io.PrintWriter;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- public class LoginAction extends HttpServlet {
- /**
- * Constructor of the object.
- */
- public LoginAction() {
- super();
- }
- /**
- * Destruction of the servlet. <br>
- */
- public void destroy() {
- super.destroy(); // Just puts "destroy" string in log
- // Put your code here
- }
- /**
- * The doGet method of the servlet. <br>
- *
- * This method is called when a form has its tag value method equals to get.
- *
- * @param request the request send by the client to the server
- * @param response the response send by the server to the client
- * @throws ServletException if an error occurred
- * @throws IOException if an error occurred
- */
- public void doGet(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- this.doPost(request, response);
- }
- /**
- * The doPost method of the servlet. <br>
- *
- * This method is called when a form has its tag value method equals to post.
- *
- * @param request the request send by the client to the server
- * @param response the response send by the server to the client
- * @throws ServletException if an error occurred
- * @throws IOException if an error occurred
- */
- public void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- response.setContentType("text/html;charset=utf-8");
- request.setCharacterEncoding("utf-8");
- response.setCharacterEncoding("utf-8");
- PrintWriter out = response.getWriter();
- String userName = request.getParameter("username");
- String passWord = request.getParameter("password");
- String json = request.getParameter("json");
- System.out.println("userName:"+userName);
- System.out.println("passWord:"+passWord);
- System.out.println("json:"+json);
- if(userName.equals("admin") && passWord.equals("123456")){
- out.print("login successful!");
- }else{
- out.print("login failed");
- }
- out.flush();
- out.close();
- }
- /**
- * Initialization of the servlet. <br>
- *
- * @throws ServletException if an error occurs
- */
- public void init() throws ServletException {
- // Put your code here
- }
- }
我们运行java project，控制台输出如下：
>>>login successful!