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 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,buf.length)) > 0) { 
    ms.write(buf,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：

PHP.weather.sina.com.cn/iframe/index/w_cl.PHP 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。

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！

原文链接：https://www.f2er.com/js/42881.html

使用UrlConnection实现后台模拟http请求的简单实例

使用UrlConnection实现后台模拟http请求的简单实例

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