线程的状态

package multiply.com.test;
public class Run {public static void main(String[] args) {try {MyThread t = new MyThread();System.out.println(" 1    Main1 method state : " + t.getState());Thread.sleep(1000);t.start();Thread.sleep(1000);System.out.println(" 2    Main1 method state : " + t.getState());} catch (InterruptedException e) {e.printStackTrace();}}
}

package multiply.com.test;
public class MyThread extends Thread {public MyThread() {System.out.println("Constuctor method state : " + Thread.currentThread().getState());}@Overridepublic void run() {super.run();System.out.println("       Run1 method state : " + Thread.currentThread().getState());}
}

Constuctor method state : RUNNABLE
1 Main1 method state : NEW
Run1 method state : RUNNABLE
2 Main1 method state : TERMINATED

线程组

线程对象关联线程组：1级关联

package multiply.com.test;
public class Run {public static void main(String[] args) {ThreadA a = new ThreadA();ThreadB b = new ThreadB();ThreadGroup group = new ThreadGroup("X process group!");Thread aThread = new Thread(group, a);Thread bThread = new Thread(group, b);aThread.start();bThread.start();System.out.println("Active process number : " + group.activeCount());System.out.println("       process  name  : " + group.getName());}
}

package multiply.com.test;
public class ThreadA extends Thread {@Overridepublic void run() {super.run();try {while (!Thread.currentThread().isInterrupted()) {System.out.println("Thread name : " + Thread.currentThread().getName());Thread.sleep(3000);}} catch (InterruptedException e) {e.printStackTrace();}}
}

package multiply.com.test;
public class ThreadB extends Thread {@Overridepublic void run() {super.run();try {while (!Thread.currentThread().isInterrupted()) {System.out.println("Thread name : " + Thread.currentThread().getName());Thread.sleep(3000);}} catch (InterruptedException e) {e.printStackTrace();}}
}

线程对象关联线程组：多级关联

获取根线程组

线程组里面加线程组

组内的线程批量停止

递归和非递归取得组内对象

传入false就是只取得子组

使线程具有有序性

package multiply.com.test;
public class Run {public static void main(String[] args) {Object lock = new Object();MyThread a = new MyThread(lock, "A", 1);MyThread b = new MyThread(lock, "B", 2);MyThread c = new MyThread(lock, "C", 0);a.start();b.start();c.start();}
}

package multiply.com.test;
public class MyThread extends Thread {private Object lock;private String showChar;private int showNumPosition;private int printCount = 0;volatile private static int addNumber = 1;public MyThread(Object lock, String showChar, int showNumPosition) {super();this.lock = lock;this.showChar = showChar;this.showNumPosition = showNumPosition;}@Overridepublic void run() {try {synchronized (lock) {while (true) {if (addNumber % 3 == showNumPosition) {System.out.println("ThreadName=" + Thread.currentThread().getName()+ " runCount=" + addNumber + " " + showChar);lock.notifyAll();addNumber++;printCount++;if (printCount == 3) {break;}} else {lock.wait();}}}} catch (InterruptedException e) {e.printStackTrace();}}
}

ThreadName=Thread-0 runCount=1 A
ThreadName=Thread-1 runCount=2 B
ThreadName=Thread-2 runCount=3 C
ThreadName=Thread-0 runCount=4 A
ThreadName=Thread-1 runCount=5 B
ThreadName=Thread-2 runCount=6 C
ThreadName=Thread-0 runCount=7 A
ThreadName=Thread-1 runCount=8 B
ThreadName=Thread-2 runCount=9 C

SimpleDateFormat非线程安全

package multiply.com.test;
import java.text.SimpleDateFormat;
public class Test {public static void main(String[] args) {SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");String[] dateStringArray = new String[] { "2000-01-01", "2000-01-02","2000-01-03", "2000-01-04", "2000-01-05", "2000-01-06","2000-01-07", "2000-01-08", "2000-01-09", "2000-01-10" };MyThread[] threadArray = new MyThread[10];for (int i = 0; i < 10; i++) {threadArray[i] = new MyThread(sdf, dateStringArray[i]);}for (int i = 0; i < 10; i++) {threadArray[i].start();}}
}

package multiply.com.test;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class MyThread extends Thread {private SimpleDateFormat sdf;private String dateString;public MyThread(SimpleDateFormat sdf, String dateString) {super();this.sdf = sdf;this.dateString = dateString;}@Overridepublic void run() {try {Date dateRef = sdf.parse(dateString);String newDateString = sdf.format(dateRef).toString();if (!newDateString.equals(dateString)) {System.out.println("ThreadName=" + this.getName()+ "报错了，日期字符串：" + dateString + " 转换成的日期为："+ newDateString);}} catch (ParseException e) {e.printStackTrace();}}
}

线程中的异常处理

线程组内异常处理

package multiply.com.test;
public class Run {public static void main(String[] args) {MyThreadGroup group = new MyThreadGroup("My Thread Group!");MyThread[] myThread = new MyThread[10];for (int i = 0; i < myThread.length; i++) {myThread[i] = new MyThread(group, "Thread " + (i + 1), "1");myThread[i].start();}MyThread t = new MyThread(group, "Exception Thread ", "AA");t.start();}
}

package multiply.com.test;
public class MyThread extends Thread {private String num;public MyThread(ThreadGroup group, String name, String num) {super(group, name);this.num = num;}@Overridepublic void run() {super.run();int numInt = Integer.parseInt(num);System.out.println(Thread.currentThread().getName() + " " + numInt);while (!this.isInterrupted()) {}}}

package multiply.com.test;
public class MyThreadGroup extends ThreadGroup {public MyThreadGroup(String name) {super(name);}@Overridepublic void uncaughtException(Thread t, Throwable e) {super.uncaughtException(t, e);this.interrupt();}
}