使用UrlConnection实现后台模拟http请求的简单实例
这两天在整理看httpclient，然后想自己用UrlConnection后台模拟实现Http请求，于是一个简单的小例子就新鲜出炉了（支持代理哦）：
public class SimpleHttpTest { public static String send(String urlStr, Map<String,String> map,String encoding){ String body=""; StringBuffer sbuf = new StringBuffer(); if(map!=null){ for (Entry<String,String> entry : map.entrySet()) { sbuf.append(entry.getKey()).append("=").append(entry.getValue()).append("&"); } if(sbuf.length()>0){ sbuf.deleteCharAt(sbuf.length()-1); } } // 1、重新对请求报文进行 GBK 编码 byte[] postData = null; try { postData = sbuf.toString().getBytes(encoding); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } // 2、发送 HTTP(S) 请求 OutputStream reqStream = null; InputStream resStream = null; URLConnection request = null; try { System.out.println("交易请求地址：" + urlStr); System.out.println("参数：" + sbuf.toString()); //A、与服务器建立 HTTP(S) 连接 URL url = null; try { Proxy proxy = new Proxy(java.net.Proxy.Type.HTTP,new InetSocketAddress("127.0.0.1", 8087)); url = new URL(urlStr); request = url.openConnection(proxy); request.setDoInput(true); request.setDoOutput(true); } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } //B、指定报文头【Content-type】、【Content-length】 与 【Keep-alive】 request.setRequestProperty("Content-type", "application/x-www-form-urlencoded"); request.setRequestProperty("Content-length", String.valueOf(postData.length)); request.setRequestProperty("Keep-alive", "false"); request.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)"); //C、发送报文至服务器 reqStream = request.getOutputStream(); reqStream.write(postData); reqStream.close(); //D、接收服务器返回结果 ByteArrayOutputStream ms = null; resStream = request.getInputStream(); ms = new ByteArrayOutputStream(); byte[] buf = new byte[4096]; int count; while ((count = resStream.read(buf, 0, buf.length)) > 0) { ms.write(buf, 0, count); } resStream.close(); body = new String(ms.toByteArray(), encoding); } catch (UnknownHostException e) { System.err.println( "服务器不可达【" + e.getMessage() + "】"); } catch (IOException e) { e.printStackTrace(); } finally { try { if (reqStream != null) reqStream.close(); if (resStream != null) resStream.close(); } catch (Exception ex) { } } System.out.println("交易响应结果："); System.out.println(body); return body; } public static void main(String[] args) { String url="http://php.weather.sina.com.cn/iframe/index/w_cl.php"; Map<String, String> map = new HashMap<String, String>(); map.put("code", "js"); map.put("day", "0"); map.put("city", "上海"); map.put("dfc", "1"); map.put("charset", "utf-8"); send(url, map,"utf-8"); } }
结果如下：
交易请求地址： 参数：dfc=1&charset=utf-8&day=0&code=js&city=上海 交易响应结果： (function(){var w=[];w['上海']=[{s1:'阴',s2:'阴',f1:'yin',f2:'yin',t1:'17',t2:'14',p1:'≤3',p2:'≤3', d1:'东北风',d2:'东北风'}];var add={now:'2015-11-11 19:04:33',time:'1447239873',update:' 北京时间11月11日17:10更新',error:'0',total:'1'};window.SWther={w:w,add:add};})();//0
代码中的步骤写的很明白了，如果你有心，还可以对该方法进行各种封装，方便使用。下篇我会分享一下httpclient是如何模拟后台来发送http请求的，还有配置ssl、代理、自定义header等等，敬请期待吧。