1:概述
HttpClient是HttpComponents(简称为hc)项目其中的一部份,访问地址:http://hc.apache.org/
HttpClient是一个代码级的Http客户端工具,可以使用它模拟浏览器向Http服务器发送请求。使用HttpClient还需要HttpCore.后者包括Http请求与Http响应的代码封装。
public final static void main(String[] args) throws Exception { HttpClient httpclient = new DefaultHttpClient(); try { HttpGet httpget = new HttpGet("http://www.apache.org/"); System.out.println("executing request " + httpget.getURI()); HttpResponse response = httpclient.execute(httpget); HttpEntity entity = response.getEntity(); System.out.println("----------------------------------------"); System.out.println(response.getStatusLine()); if (entity != null) { System.out.println("Response content length: " + entity.getContentLength()); } System.out.println("----------------------------------------"); InputStream inSm = entity.getContent(); Scanner inScn = new Scanner(inSm); while (inScn.hasNextLine()) { System.out.println(inScn.nextLine()); } // Do not feel like reading the response body // Call abort on the request object httpget.abort(); } finally { // When HttpClient instance is no longer needed, // shut down the connection manager to ensure // immediate deallocation of all system resources httpclient.getConnectionManager().shutdown(); } }
httpcore:EntityUtils.toString(httpEntity)
读取response响应内容部分,也可以借助于 httpcore-4.1.2.jar 里面的
- String content = EntityUtils.toString(httpEntity);
String content = EntityUtils.toString(httpEntity);
/** * User: liuwentao * Time: 12-1-25 下午1:23 */ public class Demo1 { /** * 用 get 方法访问 www.apache.org 并返回内容 * * @param args */ public static void main(String[] args) { //创建默认的 HttpClient 实例 HttpClient httpClient = new DefaultHttpClient(); try { //创建 httpUriRequest 实例 HttpGet httpGet = new HttpGet("http://www.apache.org/"); System.out.println("uri=" + httpGet.getURI()); //执行 get 请求 HttpResponse httpResponse = httpClient.execute(httpGet); //获取响应实体 HttpEntity httpEntity = httpResponse.getEntity(); //打印响应状态 System.out.println(httpResponse.getStatusLine()); if (httpEntity != null) { //响应内容的长度 long length = httpEntity.getContentLength(); //响应内容 String content = EntityUtils.toString(httpEntity); System.out.println("Response content length:" + length); System.out.println("Response content:" + content); } //有些教程里没有下面这行 httpGet.abort(); } catch (Exception e) { e.printStackTrace(); } finally { //关闭连接,释放资源 httpClient.getConnectionManager().shutdown(); } } }
执行结果:
httpget.setHeader
1:分析请求包中这六个头信息
2:代码
/** * @param args * @throws IOException */ public static void main(String[] args) { HttpClient httpClient = new DefaultHttpClient(); try { HttpGet httpget = new HttpGet("http://www.iteye.com"); httpget.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"); httpget.setHeader("Accept-Language", "zh-cn,zh;q=0.5"); httpget.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 5.1; rv:7.0.1) Gecko/20100101 Firefox/7.0.1)"); httpget.setHeader("Accept-Encoding", "gzip, deflate"); httpget.setHeader("Accept-Charset", "GB2312,utf-8;q=0.7,*;q=0.7"); httpget.setHeader("Host", "www.iteye.com"); httpget.setHeader("Connection", "Keep-Alive"); HttpResponse response = httpClient.execute(httpget); HttpEntity entity = response.getEntity(); System.out.println("----------------------------------------"); System.out.println(response.getStatusLine()); if (entity != null) { System.out.println("Response content length: " + entity.getContentLength()); } System.out.println("----------------------------------------"); InputStream inSm = entity.getContent(); Scanner inScn = new Scanner(inSm); while (inScn.hasNextLine()) { System.out.println(inScn.nextLine()); } // Do not feel like reading the response body // Call abort on the request object httpget.abort(); } catch (Exception e) { e.printStackTrace(); } finally { // When HttpClient instance is no longer needed, // shut down the connection manager to ensure // immediate deallocation of all system resources httpClient.getConnectionManager().shutdown(); } }
3:效果
以上乱码是由于
- httpget.setHeader("Accept-Encoding", "gzip, deflate");
注释掉这行
/** * User: liuwentao * Time: 12-1-25 下午1:23 */ public class Demo3 { /** * 用 get 方法访问 www.baidu.com 并返回内容 * * @param args */ public static void main(String[] args) { //创建默认的 HttpClient 实例 HttpClient httpClient = new DefaultHttpClient(); try { //创建 httpUriRequest 实例 HttpGet httpGet = new HttpGet("http://www.iteye.com"); httpGet.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"); httpGet.setHeader("Accept-Language", "zh-cn,zh;q=0.5"); httpGet.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 5.1; rv:7.0.1) Gecko/20100101 Firefox/7.0.1)"); // httpGet.setHeader("Accept-Encoding", "gzip, deflate"); httpGet.setHeader("Accept-Charset", "GB2312,utf-8;q=0.7,*;q=0.7"); httpGet.setHeader("Host", "www.iteye.com"); httpGet.setHeader("Connection", "Keep-Alive"); System.out.println("uri=" + httpGet.getURI()); //执行 get 请求 HttpResponse httpResponse = httpClient.execute(httpGet); //获取响应实体 HttpEntity httpEntity = httpResponse.getEntity(); //打印响应状态 System.out.println(httpResponse.getStatusLine()); if (httpEntity != null) { //响应内容的长度 long length = httpEntity.getContentLength(); //响应内容 String content = EntityUtils.toString(httpEntity); System.out.println("Response content length:" + length); System.out.println("Response content:" + content); } //有些教程里没有下面这行 httpGet.abort(); } catch (Exception e) { e.printStackTrace(); } finally { //关闭连接,释放资源 httpClient.getConnectionManager().shutdown(); } } }
效果:
用post方法访问本地应用根据传递参数不同,返回不同结果
<servlet> <servlet-name>Test1Servlet</servlet-name> <servlet-class>demo.servlet.Test1Servlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>Test1Servlet</servlet-name> <url-pattern>/test1Servlet</url-pattern> </servlet-mapping>
/** * User: liuwentao * Time: 11-12-25 下午1:08 */ public class Test1Servlet extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //接收地址栏参数 String param1 = request.getParameter("param1"); //输出 response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); out.write("你传递来的参数param1=" + param1); out.close(); } }
/** * User: liuwentao * Time: 12-1-25 下午1:23 */ public class Demo2 { /** * 用post方法访问本地应用根据传递参数不同,返回不同结果 * * @param args */ public static void main(String[] args) { //创建默认的 HttpClient 实例 HttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost("http://localhost:86/test1Servlet"); List<NameValuePair> formParams = new ArrayList<NameValuePair>(); formParams.add(new BasicNameValuePair("param1", "刘文涛")); UrlEncodedFormEntity urlEncodedFormEntity; try { urlEncodedFormEntity = new UrlEncodedFormEntity(formParams, "UTF-8"); httpPost.setEntity(urlEncodedFormEntity); System.out.println("execurting request:" + httpPost.getURI()); HttpResponse httpResponse = null; httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); if (httpEntity != null) { String content = EntityUtils.toString(httpEntity, "UTF-8"); System.out.println("Response content:" + content); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { //关闭连接,释放资源 httpClient.getConnectionManager().shutdown(); } } }
结果: