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java線程問題，直接看代碼吧。不好描述。

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德瑪西亞99 2019-04-21 20:38:54

Foo類實(shí)現(xiàn)了Runnable接口publicclassFooimplementsRunnable{privatebooleanisRun;@Overridepublicvoidrun(){isRun=true;while(isRun){System.out.println("runing......");}}publicvoidstop(){this.isRun=false;}@OverridepublicStringtoString(){return"Foo{"+"isRun="+isRun+'}';}}測試類publicclassThreadTest{publicstaticvoidmain(String[]args){Foof=newFoo();Threadt=newThread(f);t.start();f.stop();System.out.print(f);}}為什么執(zhí)行了stop()方法之后，t線程沒有停止執(zhí)行呢。我debug發(fā)現(xiàn)thread在運(yùn)行start()方法之前，里面的Foo對象和執(zhí)行stop（）方法的Foo對象是同一個(gè)。按理說執(zhí)行stop（）方法后。f的isRun被設(shè)置成了false,線程讀取到該變量變成false應(yīng)該停止才對?？磘hread的源碼求大神解答。

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紅顏莎娜

TA貢獻(xiàn)1842條經(jīng)驗(yàn) 獲得超13個(gè)贊

t.start();并不是離開執(zhí)行run方法，而是交給OS去調(diào)度。針對你這個(gè)例子，執(zhí)行的順序是f.stop()-->System.out.print(f)也及時(shí)調(diào)用f對象的toString，然后才開始線程執(zhí)行。而在你的run方法中又設(shè)置isRun=true;所以線程無法停止。修改Foo如下：publicclassFooimplementsRunnable{privateintisRun=1;@Overridepublicvoidrun(){System.out.println("isRunValue:"+isRun);isRun=0;while(isRun==0){System.out.println("runing......");try{Thread.sleep(1000l);}catch(Exceptione){}}}publicvoidstop(){this.isRun=2;}@OverridepublicStringtoString(){return"Foo{"+"isRun="+isRun+"}\n";}}這個(gè)時(shí)候你會(huì)看到類似這樣的輸出Foo{isRun=2}isRunValue:2runing......runing......runing......runing......說明stop確實(shí)在run之前先執(zhí)行

反對回復(fù) 2019-04-21

FFIVE

TA貢獻(xiàn)1797條經(jīng)驗(yàn) 獲得超6個(gè)贊

因?yàn)槟氵@是死循環(huán)while(isRun){System.out.println("runing......");}而且isRun一直是true，你應(yīng)該改成：@Overridepublicvoidrun(){//isRun=true;while(isRun){System.out.println("runing......");}}isRun一開始就初始化，應(yīng)該這么寫：publicclassFooThreadimplementsRunnable{privatebooleanisRun=true;@Overridepublicvoidrun(){System.out.println("runbegin...");//isRun=true;while(isRun){System.out.println("runing......");}}publicvoidstop(){System.out.println("callstop");this.isRun=false;}@OverridepublicStringtoString(){return"Foo{"+"isRun="+isRun+'}';}publicstaticvoidmain(String[]args){FooThreadf=newFooThread();Threadt=newThread(f);t.start();try{Thread.sleep(100);}catch(InterruptedExceptione){//TODOAuto-generatedcatchblocke.printStackTrace();}f.stop();System.out.print(f);}}最終輸出：runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......runing......callstopFoo{isRun=false}