Java线程同步方法实例总结

import java.util.concurrent.semaphore;

public class program{

     public static void main(string[] agrs){

         printqueue p= new printqueue();

         thread[] ths= new thread[ 10 ];

         for ( int i= 0 ;i< 10 ;i++){

             ths[i]= new thread( new job(p), "thread" +i);

         }

         for ( int i= 0 ;i< 10 ;i++){

             ths[i].start();

         }

     }

}

class printqueue{

     private semaphore s;

     public printqueue(){

         s= new semaphore( 1 ); //二进制信号量

     }

     public void printjob(object document){

         try {

             s.acquire();

             long duration=( long )(math.random()* 100 );

             system.out.printf( "线程名：%s 睡眠：%d" ,thread.currentthread().getname(),duration);

             thread.sleep(duration);

         }

         catch (interruptedexception e){

             e.printstacktrace();

         }

         finally {

             s.release();

         }

     }

}

class job implements runnable{

     private printqueue p;

     public job(printqueue p){

         this .p=p;

     }

     @override

     public void run(){

         system.out.printf( "%s:正在打印一个任务\n " ,thread.currentthread().getname());

         this .p.printjob( new object());

         system.out.printf( "%s:文件已打印完毕\n " ,thread.currentthread().getname());

     }

}

import java.util.concurrent.semaphore;

import java.util.concurrent.locks.lock;

import java.util.concurrent.locks.reentrantlock;

public class program{

     public static void main(string[] agrs){

         printqueue p= new printqueue();

         thread[] ths= new thread[ 10 ];

         for ( int i= 0 ;i< 10 ;i++){

             ths[i]= new thread( new job(p), "thread" +i);

         }

         for ( int i= 0 ;i< 10 ;i++){

             ths[i].start();

         }

     }

}

class printqueue{

     private semaphore s;

     private boolean [] freeprinters;

     private lock lock;

     public printqueue(){

         s= new semaphore( 3 ); //二进制信号量

         freeprinters= new boolean [ 3 ];

         for ( int i= 0 ;i< 3 ;i++){

             freeprinters[i]= true ;

         }

         lock= new reentrantlock();

     }

     public void printjob(object document){

         try {

             s.acquire();

             int printerindex=getindex();

                 long duration=( long )(math.random()* 100 );

                 system.out.printf( "线程名：%s 睡眠：%d\n" ,thread.currentthread().getname(),duration);

                 thread.sleep(duration);

                 freeprinters[printerindex]= true ; //恢复信号，供下次使用

         }

         catch (interruptedexception e){

             e.printstacktrace();

         }

         finally {

             s.release();

         }

     }

     //返回一个内部分组后的同步索引

     public int getindex(){

         int index=- 1 ;

         try {

             lock.lock();

             for ( int i= 0 ;i<freeprinters.length;i++){

                 if (freeprinters[i]){

                     freeprinters[i]= false ;

                     index=i;

                     break ;

                 }

             }

      }

      catch (exception e){

          e.printstacktrace();

      }

      finally {

          lock.unlock();

      }

      return index;

     }

}

class job implements runnable{

     private printqueue p;

     public job(printqueue p){

         this .p=p;

     }

     @override

     public void run(){

         system.out.printf( "%s:正在打印一个任务\n " ,thread.currentthread().getname());

         this .p.printjob( new object());

         system.out.printf( " %s:文件已打印完毕\n " ,thread.currentthread().getname());

     }

}

import java.util.concurrent.countdownlatch;

public class program{

     public static void main(string[] agrs){

         //开启可容纳10人的会议室

         videoconference v= new videoconference( 10 );

         new thread(v).start();

         //参与人员陆续进场

         for ( int i= 0 ;i< 10 ;i++){

             participant p= new participant(i+ "号人员" ,v);

             new thread(p).start();

         }

     }

}

class videoconference implements runnable{

     private countdownlatch controller;

     public videoconference( int num){

         controller= new countdownlatch(num);

     }

     public void arrive(string name){

         system.out.printf( "%s 已经到达！\n" ,name);

         controller.countdown();

         system.out.printf( "还需要等 %d 个成员！\n" ,controller.getcount());

     }

     @override

     public void run(){

         try {

             system.out.printf( "会议正在初始化...!\n" );

             controller.await();

             system.out.printf( "所有人都到齐了，开会吧!\n" );

         }

         catch (interruptedexception e){

             e.printstacktrace();

         }

     }

}

class participant implements runnable{

     private videoconference conference;

     private string name;

     public participant(string name,videoconference conference){

         this .name=name;

         this .conference=conference;

     }

     @override

     public void run(){

         long duration=( long )(math.random()* 100 );

         try {

             thread.sleep(duration);

             conference.arrive( this .name);

      }

      catch (interruptedexception e){

      }

     }

}

import java.util.concurrent.phaser;

import java.util.concurrent.timeunit;

import java.util.list;

import java.util.arraylist;

import java.io.file;

import java.util.date;

public class program{

     public static void main(string[] agrs){

         phaser phaser= new phaser( 3 );

         filesearch system= new filesearch( "c:\\windows" , "log" ,phaser);

         filesearch apps= new filesearch( "c:\\program files" , "log" ,phaser);

         filesearch documents= new filesearch( "c:\\documents and settings" , "log" ,phaser);

         thread systemthread= new thread(system, "system" );

         systemthread.start();

         thread appsthread= new thread(apps, "apps" );

         appsthread.start();

         thread documentsthread= new thread(documents, "documents" );

         documentsthread.start();

         try {

             systemthread.join();

             appsthread.join();

             documentsthread.join();

             } catch (interruptedexception e) {

             e.printstacktrace();

         }

         system.out.println( "terminated: " + phaser.isterminated());

     }

}

class filesearch implements runnable{

     private string initpath;

     private string end;

     private list<string> results;

     private phaser phaser;

     public filesearch(string initpath,string end,phaser phaser){

         this .initpath=initpath;

         this .end=end;

         this .results= new arraylist<string>();

         this .phaser=phaser;

     }

     private void directoryprocess(file file){

         file[] files=file.listfiles();

         if (files!= null ){

             for ( int i= 0 ;i<files.length;i++){

                 if (files[i].isdirectory()){

                     directoryprocess(files[i]);

                 }

                 else {

                     fileprocess(files[i]);

                 }

             }

         }

     }

     private void fileprocess(file file){

         if (file.getname().endswith(end)){

             results.add(file.getabsolutepath());

         }

     }

     private void filterresults(){

         list<string> newresults= new arraylist<string>();

         long actualdate= new date().gettime();

         for ( int i= 0 ;i<results.size();i++){

             file file= new file(results.get(i));

             long filedate=file.lastmodified();

             if (actualdate-filedate<timeunit.milliseconds.convert( 1 ,timeunit.days)){

                 newresults.add(results.get(i));

             }

         }

         results=newresults;

     }

     private boolean checkresults(){

         if (results.isempty()){

             system.out.printf( "%s: phase %d: 0 results.\n" ,thread.currentthread().getname(),phaser.getphase());

             system.out.printf( "%s: phase %d: end.\n" ,thread.currentthread().getname(),phaser.getphase());

             phaser.arriveandderegister();

         }

         else {

             system.out.printf( "%s: phase %d: %d results.\n" ,thread.currentthread().getname(),phaser.getphase(),results.size());

              phaser.arriveandawaitadvance();

             return true ;

         }

     }

     private void showinfo() {

         for ( int i= 0 ; i<results.size(); i++){

             file file= new file(results.get(i));

             system.out.printf( "%s: %s\n" ,thread.currentthread().getname(),file.getabsolutepath());

         }

         phaser.arriveandawaitadvance();

     }

     @override

     public void run(){

         file file= new file(initpath);

         if (file.isdirectory()){

             directoryprocess(file);

         }

         if (!checkresults()){

             return ;

         }

         filterresults();

         if (!checkresults()){

             return ;

         }

         showinfo();

         phaser.arriveandderegister();

         system.out.printf( "%s: work completed.\n" ,thread.currentthread().getname());

     }

}