第13天多線程thread創(chuàng)建能夠描述Java中運(yùn)行原理

13CPUCPUJava使用的為搶占式調(diào)度。{String(Stringname){=name;}void for(inti=1;i<=20;i++{String(Stringname){=name;}void for(inti=1;i<=20;i++{}}voideat()for(inti=1;i<=20;i++) }}}classclassThreadDemopublicstaticvoidmain(Stringargsp=new System.out.println("聽完歌吃完飯了,該睡覺了}}dos窗口會(huì)看到不停的輸出”xx在吃第幾口飯”，這樣的語句。為什ThreadThread是程序中的執(zhí)行線程。Java法是將類為Thread的子類。該子類應(yīng)重寫Thread類的run方法。創(chuàng)建對象，開啟線程。runmain另法是一個(gè)實(shí)現(xiàn)Runnable接口的類。該類然后實(shí)現(xiàn)run方法。然后RunnableThreadrunpublicpublicclassDemo01publicstaticvoidmain(String[]args)MyThreadmtnewMyThread("http://在主方法中執(zhí)行forfor(inti=0;i<10;i++){}}}publicpublicclassMyThreadextendsThreadpublicMyThread(Stringname//調(diào)用父類的String}*重寫runpublicvoidrun()for(inti=0;i<10;i++){}}}runstartrunstart開啟線程，jvm調(diào)用run方法在開啟的線程中執(zhí)行。ThreadThread類?startThreadThreadt1=new在新的線程中運(yùn)行起來了,但是我們直接創(chuàng)建Thread對象,調(diào)用start方法,該start調(diào)用的是們需要讓線程執(zhí)行的代碼。[javarun方法執(zhí)行什么代碼,所有沒寫run方法]startrun方法呢？run方法中。所以想要一個(gè)新線程執(zhí)行我們的任務(wù),必須先要開啟線程,start方法,再由線程自動(dòng)run方法,run方法--------肯定程對象中,我們查閱一下Thread的主線程的線程對象是你創(chuàng)建的嗎?很明顯不是,JVMThread類的API文檔發(fā)現(xiàn)有個(gè)方法是獲取當(dāng)前正在運(yùn)行的線程對象。還classMyThreadclassMyThreadextendsThread{//繼承//復(fù)寫其中的runpublicvoidfor(inti=1;i<=20;i++){}}}classThreadDemopublicstaticvoidmain(String[]args)MyThreadd1=newMyThread();MyThreadd2=newD1.start();//沒有開啟新線程在主線程調(diào)用rund2.start();//開啟一個(gè)新線程，新線程調(diào)用run}}字順延。如Thread-1......創(chuàng)建線程方式—Runnable創(chuàng)建線程的另法是實(shí)現(xiàn)Runnable接口的類。該類然后實(shí)現(xiàn)run方法。然Runnable的子類對象，傳入到某個(gè)線程的構(gòu)造方法中，開啟線程。Runnable接口，RunableAPIRunnable接口說明文檔：Runnable接口用來指定每個(gè)線程要執(zhí)行的任務(wù)。包含了一個(gè)run的無參數(shù)抽象方法，需要由接口實(shí)現(xiàn)類重寫該方法。1Runnable2run3ThreadpublicpublicclassDemo02publicstaticvoidmain(String[]args)Runnablerunn=new//將Runnable接口的子類對象作為參數(shù)傳遞給ThreadThreadthread=newThread(runn);Threadthread2=newThread(runn);for(inti=0;i<10;i++){}}}publicpublicclassMyRunnableimplements//定義線程要執(zhí)行的runpublicvoidrun()for(inti=0;i<10;i++){}}}Runnable的原理和第式繼承Thread類，線程對象和線程任務(wù)耦合在一起。一旦創(chuàng)建Thread類的runnableRunnable類型。RunnablenewnewThread()publicvoidrun()for(intx=0;x<40;x++){+"...X...."+}}RunnableRunnabler=newRunnable()publicvoidrun()for(intx=0;x<40;x++){+"...Y...."+}}new院要賣票，我們模擬院的賣票過程。假設(shè)要的是“功夫熊貓3”，本次的座位共100個(gè)(本場只能賣100)?？谝黄鹳u這100)publicpublicclassThreadDemopublicstaticvoidmain(String[]args)Ticketticket=new//3Threadt1=newThread(ticket,1");Threadt2=newThread(ticket,2");Threadt3=newThread(ticket,}}publicpublicclassTicketimplementsRunnable//100intticket=publicvoidrun()if(ticket>0)trytry}catch(InterruptedExceptione){}System.out.println(Thread.currentThread().getName()+"正在賣票:"+ticket--);}}}}0、-線程同步（java中提供了線程同步機(jī)制，它能夠解決上述的線程安全問題。同步代碼塊(同步鎖synchronized鎖對象}同步代碼塊:在代碼塊上synchronized鎖對象} publicpublicclassTicketimplementsRunnableintticket=Objectlock=newObject();publicvoidrun()synchronizedlock){if(ticket>0) try}catch(InterruptedExceptione){}"正在賣票ticket}}}}}publicpublicsynchronizedvoid} publicpublicclassTicketimplementsRunnable//100intticket=Objectlock=newObject();publicvoidrun()}}//同步方法,鎖對象publicsynchronizedvoidif(ticket>0)try}catch(InterruptedExceptione){}System.out.println(Thread.currentThread().getName()+"正在賣票:"+ticket--);}}}靜態(tài)同步方法:在方法上加上staticpublicpublicstaticsynchronizedvoid}靜態(tài)同步方法中的鎖對象是類名LockAPILock接口描述，Locksynchronized方法和語classclassXprivatefinalReentrantLocklock=newReentrantLock();publicvoidrun(){lock.lock();//blockuntilconditionholdstry{//...method}finally}}}publicclassTicketimplementsRunnable//100intpublicclassTicketimplementsRunnable//100intticket=//創(chuàng)建LockLockck=newpublicvoidrun()//sync