1.Thread中sleep方法作用是使当前线程等待,其他线程开始执行,如果有线程锁,sleep不会让出锁
没有加锁代码如下:
public class SynchronizedSleepMethod {public static void main(String[] args) {MoneyMethod moneyMethod = new MoneyMethod();for (int i = 0; i < 10; i++) {Thread t = new Thread(new MyThread4(moneyMethod), "t1" + i);t.start();}for (int i = 0; i < 10; i++) {Thread t = new Thread(new MyThread5(moneyMethod), "t2" + i);t.start();}}}class MyThread4 implements Runnable {MoneyMethod moneyMethod;/*** */public MyThread4(MoneyMethod moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(1000);moneyMethod.addMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();}}}class MyThread5 implements Runnable {MoneyMethod moneyMethod;/*** */public MyThread5(MoneyMethod moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(1000);moneyMethod.subMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();} // System.out.println(moneyMethod.money);// TODO Auto-generated method stub }}class MoneyMethod {int money = 200;public void addMoney() throws InterruptedException {System.out.println(Thread.currentThread().getName() + ":::run:::" + money);money++;}public void subMoney() throws InterruptedException {System.out.println(Thread.currentThread().getName() + ":::run:::" + money);money--;}}
结果如下:
t10:::run:::202
t12:::run:::202
t11:::run:::202
t13:::run:::203
t15:::run:::205
t14:::run:::204
t17:::run:::207
t19:::run:::209
t18:::run:::209
t16:::run:::207
t21:::run:::207
t24:::run:::205
t22:::run:::206
t20:::run:::206
t29:::run:::203
t28:::run:::203
t26:::run:::202
t27:::run:::201
t23:::run:::200
t25:::run:::199
加锁代码如下:
public class SynchronizedSleepMethod {public static void main(String[] args) {MoneyMethod moneyMethod = new MoneyMethod();for (int i = 0; i < 10; i++) {Thread t = new Thread(new MyThread4(moneyMethod), "t1" + i);t.start();}for (int i = 0; i < 10; i++) {Thread t = new Thread(new MyThread5(moneyMethod), "t2" + i);t.start();}}}class MyThread4 implements Runnable {MoneyMethod moneyMethod;/*** */public MyThread4(MoneyMethod moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(1000);moneyMethod.addMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();}}}class MyThread5 implements Runnable {MoneyMethod moneyMethod;/*** */public MyThread5(MoneyMethod moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(1000);moneyMethod.subMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();} // System.out.println(moneyMethod.money);// TODO Auto-generated method stub }}class MoneyMethod {int money = 200;public synchronized void addMoney() throws InterruptedException {money++;System.out.println(Thread.currentThread().getName() + ":::run:::" + money);}public synchronized void subMoney() throws InterruptedException {money--;System.out.println(Thread.currentThread().getName() + ":::run:::" + money);}}
结果如下:
t10:::run:::201 t18:::run:::202 t17:::run:::203 t12:::run:::204 t13:::run:::205 t14:::run:::206 t15:::run:::207 t16:::run:::208 t11:::run:::209 t19:::run:::210 t22:::run:::209 t21:::run:::208 t20:::run:::207 t25:::run:::206 t24:::run:::205 t23:::run:::204 t26:::run:::203 t27:::run:::202 t29:::run:::201 t28:::run:::200
2.Thread中join()方法阻塞调用此方法的线程(calling thread),直到线程t完成,此线程再继续;
没有join()方法代码如下:
public class JoinMethod {public static void main(String[] args) throws InterruptedException {MoneyMethod2 moneyMethod = new MoneyMethod2();for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread4(moneyMethod), "t1" + i);t.start(); // t.join(300);System.out.println(Thread.currentThread().getName() + ":::run:::1"+i);}for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread5(moneyMethod), "t2" + i);t.start(); // t.join(300);System.out.println(Thread.currentThread().getName() + ":::run:::2"+i);}System.out.println(Thread.currentThread().getName() + ":::finish:::");} }class MyThread4 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread4(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.addMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();}}}class MyThread5 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread5(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.subMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();} // System.out.println(moneyMethod.money);// TODO Auto-generated method stub }}class MoneyMethod2 {int money = 200;public void addMoney() throws InterruptedException {money++;System.out.println(Thread.currentThread().getName() + ":::add:::" + money);}public void subMoney() throws InterruptedException {money--;System.out.println(Thread.currentThread().getName() + ":::sub:::" + money);}}
结果:主线程会提前走掉,然后子线程执行
main:::run:::10 main:::run:::11 main:::run:::12 main:::run:::13 main:::run:::14 main:::run:::20 main:::run:::21 main:::run:::22 main:::run:::23 main:::run:::24 main:::finish::: t10:::add:::201 t12:::add:::202 t11:::add:::203 t13:::add:::204 t14:::add:::205 t21:::sub:::203 t20:::sub:::203 t24:::sub:::201 t22:::sub:::200 t23:::sub:::201
添加了join后,join的等待时间>线程执行时间,代码如下:
public class JoinMethod {public static void main(String[] args) throws InterruptedException {MoneyMethod2 moneyMethod = new MoneyMethod2();for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread4(moneyMethod), "t1" + i);t.start();t.join(3000);System.out.println(Thread.currentThread().getName() + ":::run:::1"+i);}for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread5(moneyMethod), "t2" + i);t.start();t.join(3000);System.out.println(Thread.currentThread().getName() + ":::run:::2"+i);}System.out.println(Thread.currentThread().getName() + ":::finish:::");} }class MyThread4 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread4(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.addMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();}}}class MyThread5 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread5(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.subMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();} // System.out.println(moneyMethod.money);// TODO Auto-generated method stub }}class MoneyMethod2 {int money = 200;public void addMoney() throws InterruptedException {money++;System.out.println(Thread.currentThread().getName() + ":::add:::" + money);}public void subMoney() throws InterruptedException {money--;System.out.println(Thread.currentThread().getName() + ":::sub:::" + money);}}
结果如下:
t10:::add:::201 main:::run:::10 t11:::add:::202 main:::run:::11 t12:::add:::203 main:::run:::12 t13:::add:::204 main:::run:::13 t14:::add:::205 main:::run:::14 t20:::sub:::204 main:::run:::20 t21:::sub:::203 main:::run:::21 t22:::sub:::202 main:::run:::22 t23:::sub:::201 main:::run:::23 t24:::sub:::200 main:::run:::24 main:::finish:::
加入join方法后,线程执行时间>join的等待时间时,代码如下:
public class JoinMethod {public static void main(String[] args) throws InterruptedException {MoneyMethod2 moneyMethod = new MoneyMethod2();for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread4(moneyMethod), "t1" + i);t.start();t.join(300);System.out.println(Thread.currentThread().getName() + ":::run:::1"+i);}for (int i = 0; i < 5; i++) {Thread t = new Thread(new MyThread5(moneyMethod), "t2" + i);t.start();t.join(300);System.out.println(Thread.currentThread().getName() + ":::run:::2"+i);}System.out.println(Thread.currentThread().getName() + ":::finish:::");} }class MyThread4 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread4(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.addMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();}}}class MyThread5 implements Runnable {MoneyMethod2 moneyMethod;/*** */public MyThread5(MoneyMethod2 moneyMethod) {// TODO Auto-generated constructor stubthis.moneyMethod = moneyMethod;}/** (non-Javadoc)* * @see java.lang.Runnable#run()*/@Overridepublic void run() {try {Thread.sleep(2000);moneyMethod.subMoney();} catch (InterruptedException e) {// TODO Auto-generated catch block e.printStackTrace();} // System.out.println(moneyMethod.money);// TODO Auto-generated method stub }}class MoneyMethod2 {int money = 200;public void addMoney() throws InterruptedException {money++;System.out.println(Thread.currentThread().getName() + ":::add:::" + money);}public void subMoney() throws InterruptedException {money--;System.out.println(Thread.currentThread().getName() + ":::sub:::" + money);}}
结果如下:
main:::run:::10 main:::run:::11 main:::run:::12 main:::run:::13 main:::run:::14 main:::run:::20 t10:::add:::201 main:::run:::21 t11:::add:::202 main:::run:::22 t12:::add:::203 main:::run:::23 t13:::add:::204 main:::run:::24 main:::finish::: t14:::add:::205 t20:::sub:::204 t21:::sub:::203 t22:::sub:::202 t23:::sub:::201 t24:::sub:::200
在以上代码中可以发现,在加入join()方法后主线程还是会提前走,但是所有子线程会按照执行顺序执行
3.Thread.yield()方法作用是:暂停当前正在执行的线程对象,并执行其他线程,但是有一定几率线程调度程序会将执行被暂停的线程