Android学习之Http使用Post方式进行数据提交
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】：
package com.wujay.utils;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.UnsupportedEncodingException;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.net.URLEncoder;import java.util.HashMap;import java.util.Map;public class HttpUtils {private static String PATH = "http://bdfngdg:8080/myhttp/servlet/LoginAction"; // 服务端地址private static URL url;public HttpUtils() {super();}// 静态代码块实例化urlstatic {try {url = new URL(PATH);} catch (MalformedURLException e) {e.printStackTrace();}}/** * 发送消息体到服务端 * * @param params * @param encode * @return */public static String sendPostMessage(Map<String, String> params,String encode) {StringBuilder stringBuilder = new StringBuilder();if (params != null && !params.isEmpty()) {for (Map.Entry<String, String> entry : params.entrySet()) {try {stringBuilder.append(entry.getKey()).append("=").append(URLEncoder.encode(entry.getValue(), encode)).append("&");} catch (UnsupportedEncodingException e) {e.printStackTrace();}}stringBuilder.deleteCharAt(stringBuilder.length() - 1);try {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));// 获得输出流，向服务器输出内容OutputStream outputStream = urlConnection.getOutputStream();// 写入数据outputStream.write(myData, 0, myData.length);outputStream.close();// 获得服务器响应结果和状态码int responseCode = urlConnection.getResponseCode();if (responseCode == 200) {// 取回响应的结果return changeInputStream(urlConnection.getInputStream(),encode);}} catch (IOException e) {e.printStackTrace();}}return "";}/** * 将一个输入流转换成指定编码的字符串 * * @param inputStream * @param encode * @return */private static String changeInputStream(InputStream inputStream,String encode) {// 内存流ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();byte[] data = new byte[1024];int len = 0;String result = null;if (inputStream != null) {try {while ((len = inputStream.read(data)) != -1) {byteArrayOutputStream.write(data, 0, len);}result = new String(byteArrayOutputStream.toByteArray(), encode);} catch (IOException e) {e.printStackTrace();}}return result;}/** * @param args */public static void main(String[] args) {Map<String, String> map = new HashMap<String, String>();map.put("username", "admin");map.put("password", "123456");String result = sendPostMessage(map, "UTF-8");System.out.println(">>>" + result);}}
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");System.out.println("userName:"+userName);System.out.println("passWord:"+passWord);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!