教你利用JAVA实现可以自行关闭服务器的方法

package shutdownserver;

import java.io.*;
import java.net.serversocket;
import java.net.socket;
import java.net.socketexception;
import java.net.sockettimeoutexception;
import java.util.concurrent.executorservice;
import java.util.concurrent.executors;
import java.util.concurrent.rejectedexecutionexception;
import java.util.concurrent.timeunit;

public class echoserver {
    private int port=8000;
    private serversocket serversocket;
    private executorservice executorservice; //线程池
    private final int pool_size=4; //单个cpu时线程池中工作线程的数目

    private int portforshutdown=8001; //用于监听关闭服务器命令的端口
    private serversocket serversocketshutdown;
    private boolean isshutdown=false; //服务器是否已经关闭

    private thread shutdownthread=new thread(){
        //负责关闭服务器的线程
        public void run(){
            while(!isshutdown){
                socket socketforshutdown=null;
                try{
                    socketforshutdown=serversocketshutdown.accept();
                    bufferedreader br=new bufferedreader(
                            new inputstreamreader(socketforshutdown.getinputstream())
                    );
                    string command=br.readline();
                    if (command.equals("shutdown")){
                        long begintime=system.currenttimemillis();
                        socketforshutdown.getoutputstream().write("服务器正在关闭\r\n".getbytes());
                        isshutdown=true;

                        //请求关闭线程池
                        //线程池不再接收新的任务，但会继续执行完工作队列中现有的任务
                        executorservice.shutdown();

                        //等待关闭线程池，每次等待的超时时间为30s
                        //当使用awaittermination时，主线程会处于一种等待的状态，等待线程池中所有的线程都运行完毕后才继续运行。
                        //如果等待的时间超过指定的时间，但是线程池中的线程运行完毕，那么awaittermination()返回true。执行分线程已结束
                        //如果等待的时间超过指定的时间，但是线程池中的线程未运行完毕，那么awaittermination()返回false。不执行分线程已结束
                        //如果等待时间没有超过指定时间，等待！
                        //可以用awaittermination()方法来判断线程池中是否有继续运行的线程。
                        while(!executorservice.isterminated())
                            executorservice.awaittermination(30, timeunit.seconds);
                            //关闭与echoclient客户通信的serversocket
                            serversocket.close();
                            long endtime=system.currenttimemillis();
                            socketforshutdown.getoutputstream().write(("服务器关闭，"+"关闭服务器用了"+(endtime-begintime)+"ms\r\n").getbytes());
                            socketforshutdown.close();
                            serversocketshutdown.close();
                            system.out.println("服务器关闭");
                    }
                    else {
                        socketforshutdown.getoutputstream().write("错误的命令\r\n".getbytes());
                        socketforshutdown.close();
                    }
                } catch (exception e) {
                    e.printstacktrace();
                }
            }
        }
    };

    public echoserver() throws ioexception {
        serversocket=new serversocket(port);
        //设定等待客户连接的超时时间为60s
        serversocket.setsotimeout(60000);
        serversocketshutdown=new serversocket(portforshutdown);

        //创建线程池
        executorservice= executors.newfixedthreadpool(runtime.getruntime().availableprocessors() * pool_size);
        shutdownthread.start();
        system.out.println("服务器启动");
    }

    public void service(){
        while(!isshutdown){
            socket socket=null;
            try {
                //可能会抛出sockettimeoutexception和socketexception
                socket=serversocket.accept();
                //把等待客户发送数据的超时时间设为60s
                socket.setsotimeout(60000);
                //可能会抛出rejectedexecutionexception
                executorservice.execute(new handler(socket));
            }catch (sockettimeoutexception e){
                //不必处理等待客户连接时出现的异常
            }catch (rejectedexecutionexception e) {
                try {
                    if (socket != null)
                        socket.close();
                } catch (ioexception ex) {
                    return;
                }
            }catch (socketexception e){
                if (e.getmessage().indexof("socket closed")!=-1)
                    return;
            }catch (ioexception e){
                e.printstacktrace();
            }
        }
    }

    public static void main(string[] args) throws ioexception { //main方法抛出异常，异常直接交给虚拟机，虚拟机直接结束异常
        new echoserver().service();
    }
}

//负责与单个客户通信的任务
class handler implements runnable{
    private socket socket;
    public handler(socket socket){
        this.socket=socket;
    }

    private printwriter getwriter(socket socket) throws ioexception{
        outputstream socketout=socket.getoutputstream();
        return new printwriter(socketout,true);
    }
    private bufferedreader getreader(socket socket) throws ioexception{
        inputstream socketin=socket.getinputstream();
        return new bufferedreader(new inputstreamreader(socketin));
    }
    public string echo(string msg){
        return "echo: "+msg;
    }

    @override
    public void run() {
        try{
            system.out.println("new connection accepted "+socket.getinetaddress()+":"+socket.getport());
            bufferedreader br=getreader(socket);
            printwriter pw=getwriter(socket);

            string msg=null;
            //接收和发送数据，直到通信结束
            while((msg=br.readline())!=null){
                system.out.println("from "+socket.getinetaddress()+":"+socket.getport()+">"+msg);
                pw.println(echo(msg));
                if (msg.equals("bye"))
                    break;
            }
        } catch (ioexception e) {
            e.printstacktrace();
        }finally{
            try{
                if (socket!=null)
                    socket.close();
            }catch (ioexception e){
                e.printstacktrace();
            }
        }
    }
}

package shutdownserver;

import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstreamreader;
import java.io.outputstream;
import java.net.socket;

public class adminclient {
    public static void main(string[] args){
        socket socket=null;
        try{
            socket=new socket("localhost",8001);
            //发送关闭命令
            outputstream socketout=socket.getoutputstream();
            //scanner scanner=new scanner(system.in);
            //string order=scanner.next();
            socketout.write("shutdown\r\n".getbytes());
            //接收服务器反馈
            bufferedreader br=new bufferedreader(new inputstreamreader(socket.getinputstream()));
            string msg=null;
            while ((msg=br.readline())!=null){
                system.out.println(msg);
            }
        } catch (exception e) {
            e.printstacktrace();
        }finally {
            try{
                if (socket!=null)
                    socket.close();
            } catch (ioexception e) {
                e.printstacktrace();
            }
        }
    }
}

package shutdownserver;

import java.io.*;
import java.net.socket;

public class client {
    private string host="localhost";
    private int port=8000;
    private socket socket;

    public client() throws ioexception {
        socket=new socket(host,port);
    }

    private printwriter getwriter(socket socket) throws ioexception{
        outputstream socketout=socket.getoutputstream();
        return new printwriter(socketout,true);
    }

    private bufferedreader getreader(socket socket) throws ioexception{
        inputstream socketin=socket.getinputstream();
        return new bufferedreader(new inputstreamreader(socketin));
    }

    public void talk() throws ioexception{
        try{
            bufferedreader br=getreader(socket);
            printwriter pw=getwriter(socket);
            bufferedreader localreader=new bufferedreader(new inputstreamreader(system.in));
            string msg=null;
            while((msg=localreader.readline()) != null){
                pw.println(msg);
                system.out.println(br.readline());

                if (msg.equals("bye")){
                    break;
                }
            }
        }catch (ioexception e){
            e.printstacktrace();
        }
        finally {
            try{
                socket.close();
            }catch (ioexception e){
                e.printstacktrace();
            }
        }
    }

    public static void main(string args[]) throws ioexception {
        new client().talk();
    }
}

executorservice.shutdown();

                        //等待关闭线程池，每次等待的超时时间为30s
                        //当使用awaittermination时，主线程会处于一种等待的状态，等待线程池中所有的线程都运行完毕后才继续运行。
                        //如果等待的时间超过指定的时间，但是线程池中的线程运行完毕，那么awaittermination()返回true。执行分线程已结束
                        //如果等待的时间超过指定的时间，但是线程池中的线程未运行完毕，那么awaittermination()返回false。不执行分线程已结束
                        //如果等待时间没有超过指定时间，等待！
                        //可以用awaittermination()方法来判断线程池中是否有继续运行的线程。
                        while(!executorservice.isterminated())
                            executorservice.awaittermination(30, timeunit.seconds);