Java中的ThreadUtil

ThreadUtil使API更加具体化，因而为线程编程新手提供了一定的方便性，从而简化了API。其源码如下：

package mybole;public class ThreadUtil {public static ThreadGroup getSystemThreadGroup(){ThreadGroup systemThreadGroup;ThreadGroup parentThreadGroup;systemThreadGroup = Thread.currentThread().getThreadGroup();while((parentThreadGroup = systemThreadGroup.getParent()) != null)systemThreadGroup = parentThreadGroup;return systemThreadGroup;}public static void printSystemThreadGroup(){System.out.println(getSystemThreadGroup());}public static Thread getThread(){return new Thread(new Job());}public static Thread[] getThreads(int n){Thread[] ta = new Thread[n];for(int i=0; i<ta.length; i++){ta[i] = getThread();ta[i].start();}return ta;}public static ThreadGroup[] getThreadGroup(){ThreadGroup stg = getSystemThreadGroup();int nog = stg.activeGroupCount()+1;ThreadGroup[] tga = new ThreadGroup[nog];stg.enumerate(tga);tga[tga.length - 1] = stg;return tga;}public static void print(Object[] o){for(Object x:o)System.out.println(x);}public static void print(Thread[] o){for(Thread x:o)System.out.println(x+" isAlive="+x.isAlive()+" name="+x.getName()+" isDaemon="+x.isDaemon());}public static Thread[] getThreads(){ThreadGroup stg = getSystemThreadGroup();Thread[] ta = new Thread[stg.activeCount()];stg.enumerate(ta, true);return ta;}public static void setPriority(Thread[] ta, int p){for(Thread x:ta)x.setPriority(p);}public static void setName(Thread[] ta, String n){for(Thread x:ta)x.setName(n);}public static void main(String[] args){System.out.println("Hello Thread!!");Thread[] ta = getThreads();//***************注释*****************//Thread[] ta = getThreads(3);print(ta);setPriority(ta, 10);setName(ta, "blueln");print(ta);}}

package mybole;public class Job implements Runnable{static int totalNumberOfJobs = 0;int jobNumber = 0;Job(){jobNumber = totalNumberOfJobs;totalNumberOfJobs++;}public void run(){while(true){System.out.println("t#="+jobNumber+"\t" + new java.util.Date());try{Thread.sleep((int)(Math.random()*10000));}catch(InterruptedException e){e.getMessage();}}}}

输出结果：

Hello Thread!!Thread[Reference Handler,10,system] isAlive=true name=Reference Handler isDaemon=trueThread[Finalizer,8,system] isAlive=true name=Finalizer isDaemon=trueThread[Signal Dispatcher,9,system] isAlive=true name=Signal Dispatcher isDaemon=trueThread[Attach Listener,5,system] isAlive=true name=Attach Listener isDaemon=trueThread[main,5,main] isAlive=true name=main isDaemon=falseThread[blueln,10,system] isAlive=true name=blueln isDaemon=trueThread[blueln,10,system] isAlive=true name=blueln isDaemon=trueThread[blueln,10,system] isAlive=true name=blueln isDaemon=trueThread[blueln,10,system] isAlive=true name=blueln isDaemon=trueThread[blueln,10,main] isAlive=true name=blueln isDaemon=false

将注释部分替换，无限循环被停止，以显示出特定时刻的输出，即可看到Job类打印的结果

Hello Thread!!Thread[Thread-0,5,main] isAlive=true name=Thread-0 isDaemon=falseThread[Thread-1,5,main] isAlive=true name=Thread-1 isDaemon=falseThread[Thread-2,5,main] isAlive=true name=Thread-2 isDaemon=falseThread[blueln,10,main] isAlive=true name=blueln isDaemon=falseThread[blueln,10,main] isAlive=true name=blueln isDaemon=falseThread[blueln,10,main] isAlive=true name=blueln isDaemon=falset#=0Sun Nov 20 16:05:10 CST 2011t#=1Sun Nov 20 16:05:10 CST 2011t#=2Sun Nov 20 16:05:10 CST 2011t#=2Sun Nov 20 16:05:18 CST 2011t#=1Sun Nov 20 16:05:18 CST 2011t#=0Sun Nov 20 16:05:19 CST 2011t#=2Sun Nov 20 16:05:23 CST 2011t#=1Sun Nov 20 16:05:23 CST 2011t#=0Sun Nov 20 16:05:24 CST 2011t#=0Sun Nov 20 16:05:27 CST 2011t#=0Sun Nov 20 16:05:28 CST 2011t#=1Sun Nov 20 16:05:30 CST 2011t#=2Sun Nov 20 16:05:32 CST 2011t#=2Sun Nov 20 16:05:33 CST 2011t#=1Sun Nov 20 16:05:37 CST 2011t#=0Sun Nov 20 16:05:37 CST 2011