利用Post方法进行数据提交

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);
    }
}

servlet部分

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();
    }

}