/**
     * 發起一個http請求
     */
    public static void sendHttp(){
        URL url;
        int responsecode;
        HttpURLConnection urlConnection;
        BufferedReader reader;
        String line;
        try{
            //忽略Ssl(針對12306)
            SslUtils.ignoreSsl();
            //生成一個URL對象
            url=new URL("這里填你要訪問的網址");
            /**
             * 這是為了防止12306對同一ip多次訪問進行限制
             * 這里填的ip是暫時有效的，想要獲取更多就得自己去找 搜索代理ip
             */
            System.getProperties().setProperty("proxySet", "true");
            System.setProperty("http.proxyHost", "120.78.15.63");  
            System.setProperty("http.proxyPort", "80"); 
            //打開URL
            urlConnection = (HttpURLConnection)url.openConnection();
            //偽造一個請求頭 一般網頁不用，有些網站會看你有沒有請求頭，比如 12306......
            urlConnection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0"); 
            urlConnection.setRequestProperty("Host","kyfw.12306.cn");
            urlConnection.setRequestProperty("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
            urlConnection.setRequestProperty("Accept-Language","zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");
            urlConnection.setRequestProperty("Accept-Encoding","identity");
            urlConnection.setRequestProperty("Connection","keep-alive");
            urlConnection.setRequestProperty("Upgrade-Insecure-Requests","1");
            //獲取服務器響應代碼
            responsecode=urlConnection.getResponseCode();
            //假如響應代碼為200，就是代表成功
            if(responsecode==200){
                reader=new BufferedReader(new InputStreamReader(urlConnection.getInputStream(),"UTF-8"));
                while((line=reader.readLine())!=null){
                    System.out.println(line);//在這里干你想干的事情
                }
            }else{
                System.out.println("獲取不到網頁的源碼，服務器響應代碼為："+responsecode);
            }
        }catch(Exception e){
            System.out.println("獲取不到網頁的源碼,出現異常："+e);
        }
    }

package domain;

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 SslUtils {

    public static void trustAllHttpsCertificates() throws Exception {
        TrustManager[] trustAllCerts = new TrustManager[1];
        TrustManager tm = new miTM();
        trustAllCerts[0] = tm;
        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCerts, null);
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
    }

    static class miTM implements TrustManager,X509TrustManager {
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        public boolean isServerTrusted(X509Certificate[] certs) {
            return true;
        }

        public boolean isClientTrusted(X509Certificate[] certs) {
            return true;
        }

        public void checkServerTrusted(X509Certificate[] certs, String authType)
                throws CertificateException {
            return;
        }

        public void checkClientTrusted(X509Certificate[] certs, String authType)
                throws CertificateException {
            return;
        }
    }


    public static void ignoreSsl() throws Exception{
        HostnameVerifier hv = new HostnameVerifier() {
            public boolean verify(String urlHostName, SSLSession session) {
                return true;
            }
        };
        trustAllHttpsCertificates();
        HttpsURLConnection.setDefaultHostnameVerifier(hv);
    }
}