图解用Java实现的https心跳程序

本文以图示的方式简单介绍了如何使用Java来实现心跳程序，心跳的英文单词是heartbeat. 心跳的目的是当客户端第一次向服务器端发送了请求后，在一定时间内服务器端未能将响应返回到客户端，那么客户端为了继续保持和服务器端的连接，这时客户端就会发送一个心跳到服务器端来维持这种连接，我个人的理解心跳其实也是一种请求，只不过这个请求并不携带要求服务器端要进行处理的信息（个人看法，仅供参考）。

 

好了，下面我就把客户端和服务器端的程序共享出来供大家参考。说明一下，我采用的是https响应方式，所以我会把详细的步骤呈现出来。我的操作系统是英文的，大家就将就着看吧，不过有截图，看起来也很方便啦！

 

1. 创建https服务器端所需要的证书。https是一种安全链接协议，所以在服务器端需要一个证书，关于这方面的知识大家可以去参考更为专业和详细的介绍，在这里就简单跳过了。

1.1. startrun

 

1.2. 在下列界面中输入”cmd”, 点击”Ok”

 

 

1.3. 输入创建证书的命令(Windows和Unix系统都适用) keytool -genkey -alias test -keyalg RSA -keystore D:/mykey.store, 这样就会在D:\下创建一个名为mykey.store的证书

 

 

 

 

说明：红框里面的都是要自己输入的，关键是密码，服务器端程序要使用到。

 

2. 服务器端程序

模式很固定，至于为什么要写成这样，you ask me, I ask whom, you’d better ask Google. 业务逻辑在class MyHandler的public void handle(HttpExchange t) throws IOException中实现。另外实现这个服务器端程序要用到 这是MyEclipse自带的，JDK1.6

import java.io.BufferedReader;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

 

import java.net.InetSocketAddress;

 

 

import java.security.KeyManagementException;

import java.security.KeyStore;

import java.security.KeyStoreException;

import java.security.NoSuchAlgorithmException;

import java.security.UnrecoverableKeyException;

import java.security.cert.CertificateException;

 

 

import javax.net.ssl.KeyManagerFactory;

import javax.net.ssl.SSLContext;

 

import sun.net.httpserver.HttpsServerImpl;

 

import com.sun.net.httpserver.HttpExchange;

import com.sun.net.httpserver.HttpHandler;

import com.sun.net.httpserver.HttpsConfigurator;

 

publicclass HttpsServer {

   publicstaticvoid main(String[] args) {

      com.sun.net.httpserver.HttpsServer hss;

      try {

         //Set port as 8000

         hss = HttpsServerImpl.create(new InetSocketAddress(8000),0);

          

         //Create certification lib

         KeyStore ks = KeyStore.getInstance("JKS");

         // Load certification

         ks.load(new FileInputStream("D:/key.store" ), "123456".toCharArray());

         //Create a KeyManageeFactory

         KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");

         //Initialize the KeyManageeFactory

         kmf.init(ks, "123456".toCharArray());

         //Create certification instance

         SSLContext sslContext = SSLContext.getInstance("SSLv3");

         //Initialize certification

         sslContext.init(kmf.getKeyManagers(), null, null);

         //Confighttps

         HttpsConfigurator conf = new HttpsConfigurator(sslContext);

          

         //Load configuration in https server

         hss.setHttpsConfigurator(conf);

         // creates a default executor

         hss.setExecutor(null);

         // apply MyHandler to process "/" request

          

         hss.createContext("/mytest", new MyHandler());

          

         hss.start();

          

      } catch (IOException e) {

         e.printStackTrace();

      } catch (KeyStoreException e) {

         e.printStackTrace();

      } catch (NoSuchAlgorithmException e) {

         e.printStackTrace();

      } catch (CertificateException e) {

         e.printStackTrace();

      } catch (UnrecoverableKeyException e) {

         e.printStackTrace();

      } catch (KeyManagementException e) {

         e.printStackTrace();

      }

   }

}

 

 

class MyHandler implements HttpHandler{

   privateintcount;

   publicvoid handle(HttpExchange t) throws IOException {

       

      InputStream is = t.getRequestBody();

      BufferedReader br = new BufferedReader(new InputStreamReader(is));

      String msg = null;

      while ((msg = br.readLine()) != null) {

         System.out.println("Request from client: " + msg);         

      }

      is.close();

      br.close();

       

      count ++;

      System.out.println("count: " + count);

      String response1 = "first";

      String response2 = "second";

      t.sendResponseHeaders(200, 200);

       

      OutputStream os = t.getResponseBody();

      try {

         if (count == 1) {

            System.out.println("First send response to client");

            Thread.sleep(6000);

            os.write(response1.getBytes());

         } elseif (count == 2){

            System.out.println("Second send response to client");

//            Thread.sleep(6000);

            Thread.sleep(2000);

            os.write(response2.getBytes());

         }

          

      } catch (InterruptedException e) {

         e.printStackTrace();

      }   

      os.flush();

      os.close();

   }

}

 

3. 客户端程序

如果把本机作为服务器，url中的服务器地址理论上可以写成实际IP或127.0.0.1或localhost, 但有时写成实际的IP, 程序会出问题，就不得不写成127.0.0.1或localhost, 至于原因嘛，you ask me, I ask whom, you’d better ask Google, 因为我就是个打酱油的。多看我写的注释，关键代码就是那一句啊

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.net.MalformedURLException;

import java.net.URL;

import java.security.GeneralSecurityException;

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.X509TrustManager;

 

 

publicclass HttpsClient {

   privatestatic String url = "https://127.0.0.1:8000/mytest";

   private myX509TrustManager xtm = new myX509TrustManager();

   private myHostnameVerifier hnv = new myHostnameVerifier();

 

   public HttpsClient() {

      SSLContext sslContext = null;

      try {

         sslContext = SSLContext.getInstance("TLS"); // 或SSL

         X509TrustManager[] xtmArray = new X509TrustManager[] { xtm };

         sslContext.init(null, xtmArray, new java.security.SecureRandom());

      } catch (GeneralSecurityException e) {

         e.printStackTrace();

      }

      if (sslContext != null) {

         HttpsURLConnection.setDefaultSSLSocketFactory(sslContext

               .getSocketFactory());

      }

      HttpsURLConnection.setDefaultHostnameVerifier(hnv);

   }

    

   privateintcount = 0;

   publicvoid send(String msg) {

      count ++;

      HttpsURLConnection urlCon = null;

      OutputStream os = null;;

      InputStream is = null;

      BufferedReader br = null;

      try {

         urlCon = (HttpsURLConnection) new URL(url).openConnection();

         urlCon.setDoOutput(true);

         urlCon.setRequestProperty("Content-Length", "1024");

         urlCon.setUseCaches(false);

         urlCon.setDoInput(true);

         urlCon.setRequestMethod("POST");

//         key point, set response time.

         urlCon.setReadTimeout(5000);

          

         os = urlCon.getOutputStream();

          

         os.write(msg.getBytes());

         os.flush();

         os.close();

          

         is = urlCon.getInputStream();

         br = new BufferedReader(new InputStreamReader(is));

         String line = null;

         while ((line = br.readLine()) != null) {

            System.out.println("Response from server: " + line);

            System.exit(0);

         }

      } catch (MalformedURLException e) {

         e.printStackTrace();

      } catch (IOException e) {

          

         if (count == 1) {

            System.out.println("Send heartbeat");

            send("Heartbeat");

         } elseif (count == 2) {

            System.out.println("Time is up");

         }

      } finally {

         urlCon.disconnect();

         try {

            os.close();

            is.close();

            br.close();

         } catch (IOException e) {}

      }

   }

    

   publicstaticvoid main(String[] args) {

      HttpsClient t = new HttpsClient();

      System.out.println("Send request to server");

//      try {

//         Thread.sleep(6000);

         t.send("Hello Server");

//      } catch (InterruptedException e) {

//         e.printStackTrace();

//      }

   }

    

   class myX509TrustManager implements X509TrustManager {

      publicvoid checkClientTrusted(X509Certificate[] chain, String authType) {}

      publicvoid checkServerTrusted(X509Certificate[] chain, String authType) {}

      public X509Certificate[] getAcceptedIssuers() {

         returnnull;

      }

   }

 

   class myHostnameVerifier implements HostnameVerifier {

      publicboolean verify(String hostname, SSLSession session) {

         returntrue;

      }

   }

}