前言

    Httpclient 3.X和Httpclient 4.X如何设置代理呢？现在的网络比较成熟，各种大型网站为了防止别人恶意攻击自己的网站，都会对访问者的IP进行限制，所以为了能够多次访问一个网站，Httpclient在使用过程就会遇到设置代理的问题，那么如何来给Httpclient设置代理IP呢？

    Httpclient 3.X和Httpclient 4.X的版本差距比较大，设置代理的方式各不一样.

Httpclient 3.X 设置代理的方式：

//设置不带用户和密码的代理
httpClient.getHostConfiguration().setProxy(ip, port) ;

//设置带用户和密码的代理
if(ip!=null && !ip.equals("")){
    System.out.println("使用代理:"+ip+"--"+port+"--"+httpUsername+"--"+httpPwd);
    httpClient.getHostConfiguration().setProxy(ip, port) ;
    if (StringUtils.isNotBlank(httpUsername)) {  
	UsernamePasswordCredentials upc = null;  
	upc = new UsernamePasswordCredentials(httpUsername, httpPwd);   
	httpClient.getState().setProxyCredentials(AuthScope.ANY, upc);  
    }  
}

Httpclient 4.X设置代理的方式：

if(ip!=null && !ip.equals("")){
    HttpHost proxy = new HttpHost(ip, port);
    httpClient.getParams().setParameter(ConnRouteParams.DEFAULT_PROXY, proxy);
}

Httpclient使用代理访问网页的例子:

给大家分享一个使用代理查询对IP访问限制的网站，希望有所帮助！

public class Xicidaili {
	public static void get(DefaultHttpClient httpClient, String ip, int port) {
		boolean re = false;

		if (ip != null && !ip.equals("")) {
			HttpHost proxy = new HttpHost(ip, port);
			httpClient.getParams().setParameter(ConnRouteParams.DEFAULT_PROXY,
					proxy);
		}

		if (httpClient == null) {
			httpClient = HttpClientUtuils.handleNewHttpClient(120000, 120000);			
		}

		String sg1 = "";
		HttpGet g1 = null;
		try {

			g1 = new HttpGet("https://www.xicidaili.com/nn/");
			HttpResponse response2 = httpClient.execute(g1);
			sg1 = EntityUtils.toString(response2.getEntity());
			if(response2.getStatusLine().getStatusCode() == 200 && sg1.indexOf("<table id=\"ip_list\">")!=-1
					&& sg1.indexOf("<tr class")!=-1) {
				sg1 = sg1.substring(sg1.indexOf("<table id=\"ip_list\">")) ;
				while(sg1.indexOf("<tr class")!=-1) {
					sg1 = sg1.substring(sg1.indexOf("<tr class")) ;
					String trstring = sg1.substring(0, sg1.indexOf("</tr>")) ;
					sg1 = sg1.substring(sg1.indexOf("</tr>")+4) ;
					if(trstring.indexOf("<td class=\"country\">")!=-1) {
						trstring = trstring.substring(trstring.indexOf("<td>")+4) ;
						String ips = trstring.substring(0, trstring.indexOf("</td>")).trim() ;
						trstring = trstring.substring(trstring.indexOf("<td>")+4) ;
						String ports = trstring.substring(0, trstring.indexOf("</td>")).trim() ;
						String https = ips + ":" + ports;
						System.out.println(https);
						
					}
				}
			}

		} catch (Exception e) {
			System.out.println(e.toString());
		} finally {
			if (httpClient != null) {
				httpClient.getConnectionManager().shutdown();
			}
		}

		sg1 = null;
		System.gc();

		return;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {		
		Xicidaili is_address_right_hm = new Xicidaili();
		is_address_right_hm.get(null, "", 0, null);
	}
}

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