有时候我们需要进行远程调用，跨域，有很多可选方案，例如 jsonp ，RMI,   HttpClient.

我感觉 HttpClient属于一次写好，以后只要直接用就可以了，很方便，节约时间。

/* * 利用HttpClient进行post请求的工具类 */public class HttpClientUtil {		public static String doPost(String url,Map
    
      map,String charset){		HttpClient httpClient = null;		HttpPost httpPost = null;		String result = null;		try{			httpClient = new SSLClient();			httpPost = new HttpPost(url);			//设置参数			List
     
       list = new ArrayList
      
       ();			Iterator
       
        
         > iterator = map.entrySet().iterator();			while(iterator.hasNext()){				Entry
         
           elem = (Entry
          
           ) iterator.next(); list.add(new BasicNameValuePair(elem.getKey(),elem.getValue())); } if(list.size() > 0){ UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list,charset); httpPost.setEntity(entity); } HttpResponse response = httpClient.execute(httpPost); if(response != null){ HttpEntity resEntity = response.getEntity(); if(resEntity != null){ result = EntityUtils.toString(resEntity,charset); } } }catch(Exception ex){ ex.printStackTrace(); } return result; }}
          
         
        
       
      
     
    

public class SSLClient  extends DefaultHttpClient{	public SSLClient() throws Exception{        super();        SSLContext ctx = SSLContext.getInstance("TLS");        X509TrustManager tm = new X509TrustManager() {                public void checkClientTrusted(X509Certificate[] chain,                        String authType) throws CertificateException {                }                public void checkServerTrusted(X509Certificate[] chain,                        String authType) throws CertificateException {                }                public X509Certificate[] getAcceptedIssuers() {                    return null;                }        };        ctx.init(null, new TrustManager[]{tm}, null);        SSLSocketFactory ssf = new SSLSocketFactory(ctx,SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);        ClientConnectionManager ccm = this.getConnectionManager();        SchemeRegistry sr = ccm.getSchemeRegistry();        sr.register(new Scheme("https", 443, ssf));    }}

调用：

/**	 *方法用途：使用	 *@param args	 *2017年1月11日	 */	public static void main(String[] args) {		String url="";		Map
    
      param=new HashMap
     
      ();		String charset="utf-8";		String result=doPost(url,param,charset);		System.out.println(result);	}
     
    

param 的 key 为参数名称， value 为参数的值。对方可以用过 request.getParameter("");得到值。