HttpUrlConnection Post提交数据到服务器、并得到服务器返回的数据

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url

static {

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：

[html] view
plaincopy

<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:

[html] view
plaincopy

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")){

//返回给android客户端的值就是login successful!

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

}



}