今天看了看Java并发程序,写一写入门程序,并设置了线程的优先级。
class Elem implements Runnable{ public static int id = 0 ; private int cutDown = 5 ; private int priority; public void setPriority( int priority){ this .priority = priority; } public int getPriority(){ return this .priority; } public void run(){ Thread.currentThread().setPriority(priority); int threadId = id ++ ; while (cutDown -- > 0 ){ double d = 1.2 ; while (d < 10000 ) d = d + (Math.E + Math.PI) / d; System.out.println( " # " + threadId + " ( " + cutDown + " ) " ); } }} public class Basic { public static void main(String args[]){ for ( int i = 0 ; i < 10 ; i ++ ){ Elem e = new Elem(); if (i == 0 ) e.setPriority(Thread.MAX_PRIORITY); else e.setPriority(Thread.MIN_PRIORITY); Thread t = new Thread(e); t.start(); } }}
由于机器很强悍,所以先开始并没看到并发的效果,感觉是按顺序执行的,所以在中间加了浮点数的运算来延迟时间。
当然,main函数里面可以用Executors来管理线程。
import java.util.concurrent. * ; class Elem implements Runnable{ public static int id = 0 ; private int cutDown = 5 ; private int priority; public void setPriority( int priority){ this .priority = priority; } public int getPriority(){ return this .priority; } public void run(){ Thread.currentThread().setPriority(priority); int threadId = id ++ ; while (cutDown -- > 0 ){ double d = 1.2 ; while (d < 10000 ) d = d + (Math.E + Math.PI) / d; System.out.println( " # " + threadId + " ( " + cutDown + " ) " ); } }} public class Basic { public static void main(String args[]){ // for(int i = 0; i < 10; i++){ // Elem e = new Elem(); // if(i == 0 ) // e.setPriority(Thread.MAX_PRIORITY); // else // e.setPriority(Thread.MIN_PRIORITY); // Thread t = new Thread(e); // t.start(); // } ExecutorService exec = Executors.newCachedThreadPool(); for ( int i = 0 ; i < 10 ; i ++ ){ Elem e = new Elem(); if (i == 0 ) e.setPriority(Thread.MAX_PRIORITY); else e.setPriority(Thread.MIN_PRIORITY); exec.execute(e); } exec.shutdown(); }}