Java实现Linux下双守护进程

 public class GuardA {
     // GuardA用于维持自己的锁
     private File fileGuardA;
     private FileOutputStream fileOutputStreamGuardA;
     private FileChannel fileChannelGuardA;
     private FileLock fileLockGuardA;
     // GuardB用于检测B的锁
     private File fileGuardB;
     private FileOutputStream fileOutputStreamGuardB;
     private FileChannel fileChannelGuardB;
     private FileLock fileLockGuardB;
 
     public GuardA() throws Exception {
         fileGuardA = new File(Configure.GUARD_A_LOCK);
         if (!fileGuardA.exists()) {
             fileGuardA.createNewFile();
         }
         //获取文件锁，拿不到证明GuardA已启动则退出
         fileOutputStreamGuardA = new FileOutputStream(fileGuardA);
         fileChannelGuardA = fileOutputStreamGuardA.getChannel();
         fileLockGuardA = fileChannelGuardA.tryLock();
         if (fileLockGuardA == null) {
             System.exit(0);
         }
        
         fileGuardB = new File(Configure.GUARD_B_LOCK);
         if (!fileGuardB.exists()) {
             fileGuardB.createNewFile();
         }
         fileOutputStreamGuardB = new FileOutputStream(fileGuardB);
         fileChannelGuardB = fileOutputStreamGuardB.getChannel();
     }
 
     /**
      * 检测B是否存在
      *
      * @return true B已经存在
      */
     public boolean checkGuardB() {
         try {
             fileLockGuardB = fileChannelGuardB.tryLock();
             if (fileLockGuardB == null) {
                 return true;
             } else {
                 fileLockGuardB.release();
                 return false;
             }
         } catch (IOException e) {
             System.exit(0);
             // never touch
             return true;
         }
     }
 }

 public class GuardServer {
     private String servername;
 
     public GuardServer(String servername) {
         this.servername = servername;
     }
 
     public void startServer(String cmd) throws Exception {
         System.out.println("Start Server : " + cmd);
         //将命令分开
 //        String[] cmds = cmd.split(" ");
 //        ProcessBuilder builder = new ProcessBuilder(cmds);
    
         //
         ProcessBuilder builder=new ProcessBuilder(new String[]{"/bin/sh","-c",cmd});
         //将服务器程序的输出定位到/dev/tty
         builder.redirectOutput(new File("/dev/tty"));
         builder.redirectError(new File("/dev/tty"));
         builder.start(); // throws IOException
         Thread.sleep(10000);
     }
 
     /**
      * 检测服务是否存在
      *
      * @return 返回配置的java程序的pid
      * @return pid >0 返回的是 pid <=0 代表指定java程序未运行
      * **/
     public int checkServer() throws Exception {
         int pid = -1;
         Process process = null;
         BufferedReader reader = null;
         process = Runtime.getRuntime().exec("jps -l");
         reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
         String line;
         while ((line = reader.readLine()) != null) {
             String[] strings = line.split("\\s{1,}");
             if (strings.length < 2)
                 continue;
             if (strings[1].contains(servername)) {
                 pid = Integer.parseInt(strings[0]);
                 break;
             }
         }
         reader.close();
         process.destroy();
         return pid;
     }
 }

 public class GuardAMain {
     public static void main(String[] args) throws Exception {
         GuardA guardA = new GuardA();
         Configure configure = new Configure();
         GuardServer server = new GuardServer(configure.getServername());
         while (true) {
             // 如果GuardB未运行 运行GuardB
             if (!guardA.checkGuardB()) {
                 System.out.println("Start GuardB.....");
                 Runtime.getRuntime().exec(configure.getStartguardb());
             }
             // 检测服务器存活
             if (server.checkServer() <= 0) {
                 boolean isServerDown = true;
                 // trip check
                 for (int i = 0; i < 3; i++) {
                     // 如果服务是存活着
                     if (server.checkServer() > 0) {
                         isServerDown = false;
                         break;
                     }
                 }
                 if (isServerDown)
                     server.startServer(configure.getStartserver());
             }
             Thread.sleep(configure.getInterval());
         }
     }
 }

 public class ShutDown {
     public static void main(String[] args) throws Exception {
         Configure configure = new Configure();
         System.out.println("Shutdown Guards..");
         for (int i = 0; i < 3; i++) {
             Process p = Runtime.getRuntime().exec("jps -l");
             BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
             String line;
             while ((line = reader.readLine()) != null) {
                 if (line.toLowerCase().contains("Guard".toLowerCase())) {
                     String[] strings = line.split("\\s{1,}");
                     int pid = Integer.parseInt(strings[0]);
                     Runtime.getRuntime().exec(configure.getKillcmd() + " " + pid);
                 }
             }
             p.waitFor();
             reader.close();
             p.destroy();
             Thread.sleep(2000);
         }
         System.out.println("Guards is shutdown");
     }
 }