java基礎(chǔ)課程14-第十四章多線程

Java基礎(chǔ)課程第十四章簡本課件由網(wǎng)新()軟件 （以下簡稱：網(wǎng)新）編制，網(wǎng)新仿真實訓(xùn)的學(xué)網(wǎng)新享有本課件中的文字?jǐn)⑹?、文檔格式、插圖、等所有信息資料的，受知識法及法等法律、的保護(hù)。任何個人或組織網(wǎng)新的 ，網(wǎng)新保留 上節(jié)課回 本課目線程的通訊（難點什么是線一個程序由一個或多個進(jìn)程組成的，一個進(jìn)程包含一個或多個線程進(jìn)程(process)本質(zhì)上是一個可執(zhí)行的程序。操作系統(tǒng)引入進(jìn)程概念象實例對應(yīng)一個線程多線程則指的是在單個程序中可以同時運行多個不同的線什么是線 。 線程的調(diào)搶占式：高優(yōu)先級的線程搶占classMythreadextendsThreadpublicstaticvoidmain(Stringargs[])Threadt=tryfor(inti=0;i<3;i++)

輸出每個 暫停1500catch(InterruptedExceptione)}}ThreadThreadrunclassmythreadextendsThread{publicvoidrun**}Runnablerun。classmythreadimplementsRunnable{publicvoidrun(){/*實現(xiàn)該方法*/}}startMythreadt=newstartrun()Thread(Stringname)構(gòu)造名稱為name classMyThread1extendsThreadpublicstaticvoidmain(Stringargs[])Threadt=

或者使implementsMyThread1ex=new}publicvoidrun()}}Born)Ready)start(Running睡眠(Slee ):線程的執(zhí)行可通過使用sleep()方法來Waiting)waitResume)以說它已被恢復(fù)。阻塞(Blocked)– ，線程就處 狀態(tài)。現(xiàn)在也不使用stop()方法新線程（新建

線程生命周ThreadstateNe

sleep()timeouorthreadjoin()orinterupt(

OtherwiseBlockedorstart( sleep(orjoin(Runnabl

Schedule

Runnin

run()complete

DeaLocavailabl synchronized(Blockedinobject`swait()pool

notify(interupt()

Blockedinobject`slockpool新死死注意stop()方法已經(jīng)被作

CPUsleep(waityieldCPUclassThreadStateDemoextendsThreadThreadpublicThreadStateDemo()t=newSystem.out.printlntSystem.out.printlnt.start();publicvoidrun()try{ System.out.printlntcatch(InterruptedExceptionIE)System.out.println");}publicstaticvoidmain(Stringargs[])newThreadStateDemo();線程類常用方currentThread()返回當(dāng)前運行的Thread對象。start(run()線程體,由start()方法調(diào)用,當(dāng)run()方法返sleep(intn)使線程睡眠n毫秒,n毫秒后,線程可線程類常用方resume()恢復(fù)掛起的線程,使其處于可運行狀態(tài)yield()將CPU控制權(quán)主動移交到下一個可運行線setName()設(shè)置線程的名字。isAlive()如果線程已被啟動并且未被終止，那么isAlive()返回true。如果返回false，則該線程是線程調(diào)讓處于運行狀態(tài)的線程調(diào)用Thread.sleep讓處于運行狀態(tài)的線程調(diào)用Thread.yield讓處于運行狀態(tài)的線程調(diào)用另一個線程的join()線程睡眠：Thread.sleep()方publicclassMyThreadextendsThread{publicvoidrun(){for(inttry{Thread.sleep(100);}catch(InterruptedExceptione){}}}publicstaticvoidmain(Stringargs[]){MyThreadt1=newMyThread();MyThreadt2=newMyThread();}}線程讓步：Thead.yield()方publicclassMyThreadextendsThread{publicvoidrun(){for(intSystem.out.println(Thread.currentThread().getName()+"}}publicstaticvoidmain(Stringargs[]){MyThreadt1=newMyThread();MyThreadt2=newMyThread();}}等待其他線程結(jié)束publicclassMachineextendsThread{publicvoidrun(){for(inta=0;a<10;a++)}publicstaticvoidmain(Stringargs[])throwsException{Machinemachine=newMachine();();}}線程類 publicfinalvoidsetDaemon(booleanpublicfinalbooleanisDaemon線程(精靈線程可以用方法publicbooleanisDaemon()確定一個線程是否守護(hù)線程，也可以用方法publicvoidsetDaemon(boolean)來設(shè)定一個線程為守護(hù)線程。 JavaThreadNORM_PRIORITYMAX_PRIORITYMIN_PRIORITYfinalvoidsetPriority(intnewp)finalintgetPriority共享資源的競當(dāng)多個線程共些數(shù)據(jù)，它們的操作會競爭共享資源，這以一個生產(chǎn)者(Producer)，消費者(Consumer)為例，生產(chǎn)

堆棧privateStringintpoint=-1;…publicStringpop()Stringgoods=buffer[point];

push()

}publicvoidpush(Stringgoods){}生產(chǎn)者線classProducerextendsThread{privateStacktheStack;privateStringbuffer[3]buffer[2]buffer1]publicbuffer[3]buffer[2]buffer1]theStack=;

}publicvoidrun(){Stringgoods;for(inti=0;i<200;i++)System.out.println(name+":push"+goods+"to}}消費者線classConsumerextendsThreadprivateStringname;publicConsumer(Stacks,Stringname){=name;buffer[3]buffer[2]buffer[3]buffer[2]buffer1];

消費者線

}publicvoidrun(){Stringgoods;for(inti=0;i<200;i++){goods=theStack.pop();+":pop"+goods+"from"+theStack.getName());}}}創(chuàng)建生產(chǎn)者和消費者線publicclassTestpublicstaticvoidmain(Stringargs[]){Stackstack=newStack("stack1");Producerproducer1=newProducer(stack,"producer1");Consumerconsumer1=newConsumer(stack,"consumer1");}}生產(chǎn) 消費堆堆共享資源的競打打印結(jié)果producer1:pushgoods0tostack1consumer1:popnullfromstack1producer1:pushgoods0tostack1…線程的同同步是一種保證共享資源完整性publicStringpop(){Stringgoods=return

publicsynchronizedStringpop(){Stringgoods=buffer[point];}}} 堆棧的方法同classStack…publicsynchronizedintgetPoint(){returnpoint;}publicsynchronizedStringpop(){…}publicsynchronizedvoidpush(Stringgoods)}線程同修改完代碼以線程同在Product類的runstack線程 機(jī)制，在Java5之前，我們只能使用synchronized來鎖定。們使用ReentrantLock保證代碼線程安全privatestaticReentrantLocklock=new//執(zhí)行后釋放 堆棧的方法同 堆棧的方法同線程同步的特線程的同步的特publicstaticvoidmain(Stringargs[])Stackstack1=newProducerproducer1=newProducer(stack1,"producer1");Producerproducer2=newProducer(stack1,"producer2");Producerproducer3=newProducer(stack1,"producer3");Consumerconsumer1=newConsumer(stack1,"consumer1");Stackstack2=newStack("stack2");Producerproducer4=newProducer(stack2,"producer4");Consumerconsumer2=newConsumer(stack2,"consumer2");}}線程的同步的特

Stack1

wait()、notify()和notifyAll()方法。Objectfinal調(diào)用notify()方法。notify(waitnotifyAll(wait調(diào)用的線程放棄線程通 S生產(chǎn)者與消費者線程通classStack…publicsynchronizedStringpop(){}Stringgoods=buffer[point];point--return}publicsynchronizedvoidpush(Stringgoods){}生產(chǎn)者與消費者線程通classStack…publicsynchronizedvoidpush(Stringgoods){}}}生產(chǎn)者與消費者線程通publicclassTestpublicstaticvoidmain(Stringargs[]){Stackstack1=newStack("stack1");Producerproducer1=newProducer(stack1,"producer1");Consumerconsumer1=newConsumerconsumer2=new}}}生產(chǎn)者與消費者線程通–（1）執(zhí)行this.notifyAll()方法，此時this的stack1（2）由于point為-1，因此執(zhí)行this.wait()方法，生產(chǎn)者與消費者線程通 終止線 實際編程中，一般是定義一個標(biāo)志變量，然后通過程序來改變標(biāo)志變量的值，從而控制線run()方法中自然退出。終止線publicclassMyThreadStopextendsThread{inta;booleanflag=false;publicvoidrun(){}}publicvoidsetFlag(boolean_flag){}publicstaticvoidmain(Stringargs[]){try{Thread.sleep(1000);}catch(Exception}}死死classOperatorimplementsRunn