Java设置代理的两种方式（HTTP和HTTPS）

直接设置系统属性，设置后所有网络请求都有效

System.setProperty("proxyType", "4");
System.setProperty("proxyPort", "80"));
System.setProperty("proxyHost", "127.0.0.1");
System.setProperty("proxySet", "true");

使用java.net.Proxy类

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.Proxy.Type;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class HttpAndHttpsProxy {

    public static String HttpsProxy(String url, String param, String proxy, int port) {
        HttpsURLConnection httpsConn = null;
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        BufferedReader reader = null;
        try {
            URL urlClient = new URL(url);
            System.out.println("请求的URL========：" + urlClient);

                SSLContext sc = SSLContext.getInstance("SSL");
                // 指定信任https
                sc.init(null, new TrustManager[] { new TrustAnyTrustManager() }, new java.security.SecureRandom());
                //创建代理虽然是https也是Type.HTTP
                Proxy proxy1=new Proxy(Type.HTTP, new InetSocketAddress(proxy, port));
                //设置代理
                httpsConn = (HttpsURLConnection) urlClient.openConnection(proxy1);

                httpsConn.setSSLSocketFactory(sc.getSocketFactory());
                httpsConn.setHostnameVerifier(new TrustAnyHostnameVerifier());
                 // 设置通用的请求属性
                httpsConn.setRequestProperty("accept", "*/*");
                httpsConn.setRequestProperty("connection", "Keep-Alive");
                httpsConn.setRequestProperty("user-agent",
                        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
                // 发送POST请求必须设置如下两行
                httpsConn.setDoOutput(true);
                httpsConn.setDoInput(true);
                // 获取URLConnection对象对应的输出流
                out = new PrintWriter(httpsConn.getOutputStream());
                // 发送请求参数
                out.print(param);
                // flush输出流的缓冲
                out.flush();
                // 定义BufferedReader输入流来读取URL的响应
                in = new BufferedReader(
                        new InputStreamReader(httpsConn.getInputStream()));
                String line;
                while ((line = in.readLine()) != null) {
                    result += line;
                }
                // 断开连接
                httpsConn.disconnect();
                System.out.println("====result====" + result);
                System.out.println("返回结果：" + httpsConn.getResponseMessage());

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
            }
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (out != null) {
                out.close();
            }
        }

         return result;
    }

    public static String HttpProxy(String url, String param, String proxy, int port) {
        HttpURLConnection httpConn = null;
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        BufferedReader reader = null;
        try {
            URL urlClient = new URL(url);
            System.out.println("请求的URL========：" + urlClient);
                //创建代理
                Proxy proxy1=new Proxy(Type.HTTP, new InetSocketAddress(proxy, port));
                //设置代理
                httpConn = (HttpURLConnection) urlClient.openConnection(proxy1);
                // 设置通用的请求属性
                httpConn.setRequestProperty("accept", "*/*");
                httpConn.setRequestProperty("connection", "Keep-Alive");
                httpConn.setRequestProperty("user-agent",
                        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
                // 发送POST请求必须设置如下两行
                httpConn.setDoOutput(true);
                httpConn.setDoInput(true);
                // 获取URLConnection对象对应的输出流
                out = new PrintWriter(httpConn.getOutputStream());
                // 发送请求参数
                out.print(param);
                // flush输出流的缓冲
                out.flush();
                // 定义BufferedReader输入流来读取URL的响应
                in = new BufferedReader(
                        new InputStreamReader(httpConn.getInputStream()));
                String line;
                while ((line = in.readLine()) != null) {
                    result += line;
                }
                // 断开连接
                httpConn.disconnect();
                System.out.println("====result====" + result);
                System.out.println("返回结果：" + httpConn.getResponseMessage());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
            }
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (out != null) {
                out.close();
            }
        }

         return result;
    }

    private static class TrustAnyTrustManager implements X509TrustManager {

        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        public X509Certificate[] getAcceptedIssuers() {
            return new X509Certificate[] {};
        }
    }

    private static class TrustAnyHostnameVerifier implements HostnameVerifier {
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    }

    public static void main(String[] args) {
        HttpsProxy("https://www.baidu.com/", "", "127.0.0.1", 81);
        HttpProxy("http://www.appblog.cn/", "", "127.0.0.1", 81);
    }
}