Http_Post

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 Http_Post {// 请求服务器端的urlprivate static String PATH = "http://192.168.1.125:8080/myhttp/servlet/LoginAction";private static URL url;public Http_Post() {// TODO Auto-generated constructor stub}static {try {url = new URL(PATH);} catch (MalformedURLException e) {// TODO Auto-generated catch blocke.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();try {if (params != null && !params.isEmpty()) {  for (Map.Entry<String, String> entry : params.entrySet()) {// 完成转码操作buffer.append(entry.getKey()).append("=").append(URLEncoder.encode(entry.getValue(), encode)).append("&");}buffer.deleteCharAt(buffer.length() - 1);}// System.out.println(buffer.toString());// 删除掉最有一个&System.out.println("-->>"+buffer.toString());HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();urlConnection.setConnectTimeout(3000);urlConnection.setRequestMethod("POST");urlConnection.setDoInput(true);// 表示从服务器获取数据urlConnection.setDoOutput(true);// 表示向服务器写数据// 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();// 获得服务器响应的结果和状态码int responseCode = urlConnection.getResponseCode();if (responseCode == 200) {return changeInputStream(urlConnection.getInputStream(), encode);}} catch (UnsupportedEncodingException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.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) {// TODO Auto-generated method stubByteArrayOutputStream 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 blocke.printStackTrace();}}return result;}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubMap<String, String> params = new HashMap<String, String>();params.put("username", "admin");params.put("password", "123");String result = Http_Post.sendPostMessage(params, "utf-8");System.out.println("--result->>" + result);}}