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://169.254.32.172:8080/myhttp/LoginAction";

    private static URL url;

    public HttpUtils() {

        // TODO Auto-generated constructor stub

    }

    static {

        try {

            url = new URL(PATH);

        } catch (MalformedURLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

    /**

     *

     * @param params

     *            填写的URL的参数

     * @param encode

     *            字节编码

     * @return

     */

    public static String sendPostMessage(Map<String, String> params,

            String encode) {

        // 作为StringBuffer初始化的字符串

        StringBuffer buffer = new StringBuffer();

        // buffer.append("?");

        try {

            if (params != null && !params.isEmpty()) {

                for (Map.Entry<String, String> entry : params.entrySet()) {

                    buffer.append(entry.getKey())

                            .append("=")

                            .append(URLEncoder.encode(entry.getValue(), encode))

                            .append("&");

                }

            }

            // 删除掉最后一个&

            // buffer.deleteCharAt(buffer.length()-1);

            System.out.println(buffer.toString());

            HttpURLConnection urlConnection = (HttpURLConnection) url

                    .openConnection();

            urlConnection.setConnectTimeout(3000);

            urlConnection.setRequestMethod("POST");

            urlConnection.setDoInput(true);// 从服务器读数据

            urlConnection.setDoOutput(true);// 向服务器写数据

            // 获得上传信息的字节大小以及长度

            byte[] mydata = buffer.toString().getBytes();

            // 表示设置请求体的类型是文本类型

            urlConnection.setRequestProperty("Content-Type",

                    "application/x-www-form-urlencoded");

            urlConnection.setRequestProperty("Content-Length",

                    String.valueOf(mydata.length));

            // 获得输出流，向服务器输出数据

            OutputStream outputStream = urlConnection.getOutputStream();

            outputStream.write(mydata, 0, mydata.length);

            outputStream.close();

            // 获得服务器响应码

            int responseCode = urlConnection.getResponseCode();

            if (responseCode == 200) {

                return changeInputStream(urlConnection.getInputStream(), encode);

            }

        } catch (UnsupportedEncodingException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            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) {

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

        byte[] data = new byte[1024];

        int len = 0;

        String result = "";

        if (inputStream != null) {

            try {

                while ((len = inputStream.read(data)) != -1) {

                    outputStream.write(data, 0, len);

                }

                result = new String(outputStream.toByteArray(), encode);

            } catch (IOException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

        }

        return result;

    }

    public static void main(String[] args) {

        Map<String, String> params = new HashMap<String, String>();

        params.put("username", "123");

        params.put("password", "123");

        sendPostMessage(params, "utf-8");

        String result = sendPostMessage(params, "utf-8");

        System.out.println(result);

    }

}

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 {

    /**

     * 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 {

        response.setContentType("text/html");

        PrintWriter out = response.getWriter();

        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");

        System.out.println(username);

        String password=request.getParameter("password");

        System.out.println(password);

        if(username.equals("123")){

            out.println("Success");

        }else{

            out.print("fail");

        }

        out.flush();

        out.close();

    }

}