使用Apache HttpClient访问JSP发送GET和POST请求
本示例说明了如何使用Apache HttpClient发送GET和POST请求，以及如何发送表单数据，详见代码及说明。对于ASP.NET的网站请求，可以查看使用Apache HttpClient访问ASP.NET发送GET和POST请求
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说明：
1、发送表单POST请求时，需要借助HttpWatch或有这种功能的小工具来查看发给服务器的参数有哪些；
2、对于POST请求的表单数据，需要创建BasicNameValuePair对象的集合，然后构造成UrlEncodedFormEntity对象，再赋值到HttpPost对象的Entity中；
3、请求发送后可以使用response2.getStatusLine().getStatusCode()，获取HTTP的状态码；
4、使用HttpResponse对象的getHeaders("")或getAllHeaders方法可以获取相应头；
5、若要获取相应的内容，可以使用HttpResponse的getEntity()获取HttpEntity对象，然后再调用它的getContent()方法，获取一个输出流(InputStream对象)
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Apache HttpClient 版本 4.0.3
下载地址：http://hc.apache.org/downloads.cgi
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package com.zywang.http;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;import org.apache.http.Header;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;/** * 使用HttClient访问JSP示例 * @author ZYWANG */public class HttpClientForJSP {public static void main(String[] args)throws ClientProtocolException, IOException {HttpClient client = new DefaultHttpClient();get(client,"http://localhost:8080/PMS");loginPost(client);client.getConnectionManager().shutdown();}/** * 模拟POST请求 * @param client * @throws UnsupportedEncodingException * @throws IOException * @throws ClientProtocolException */private static void loginPost(HttpClient client)throws UnsupportedEncodingException, IOException,ClientProtocolException {System.out.println("==========登录：====================================");HttpPost post = new HttpPost("http://localhost:8080/PMS/LoginCheck.do");//创建表单参数列表List<NameValuePair> qparams = new ArrayList<NameValuePair>();qparams.add(new BasicNameValuePair("method", "check"));qparams.add(new BasicNameValuePair("userid", "zywang"));qparams.add(new BasicNameValuePair("userpassword", "111111"));//填充表单post.setEntity(new UrlEncodedFormEntity(qparams,"UTF-8"));HttpResponse response2 = client.execute(post);int statusCode = response2.getStatusLine().getStatusCode();System.out.println("statusCode:"+statusCode);if(statusCode==200){HttpEntity entity2 = response2.getEntity();BufferedReader reader2 = new BufferedReader(new InputStreamReader(entity2.getContent()));String buffer2;while((buffer2=reader2.readLine())!=null){System.out.println(buffer2);}}else if(statusCode == 302){//302表示重定向Header[] hs = response2.getHeaders("Location");if(hs.length>0){String url = hs[0].getValue();post.abort();get(client,url);}}}/** * 模拟GET请求 * @param client * @param url * @throws IOException * @throws ClientProtocolException */private static void get(HttpClient client,String url) throws IOException,ClientProtocolException {System.out.println("======GET:"+url+"===========================");HttpGet get = new HttpGet(url);HttpResponse response = client.execute(get);HttpEntity entity = response.getEntity();BufferedReader reader = new BufferedReader(new InputStreamReader(entity.getContent(),"UTF-8"));String buffer = null;while((buffer=reader.readLine())!=null){System.out.println(buffer);}get.abort();}}?