Java setPriority()方法
线程类的
setPriority()方法用于更改线程的优先级。每个线程都有一个优先级，该优先级由1到10之间的整数表示。
线程类提供3个常量属性:
公共静态整数MIN_PRIORITY: 它是线程的最大优先级。它的值为1。
公共静态int NORM_PRIORITY: 这是线程的正常优先级。它的值为5。
公共静态整数MAX_PRIORITY: 这是线程的最低优先级。它的值为10。
我们还可以将线程的优先级设置为1到10。此优先级称为自定义优先级或用户定义的优先级。
语法
public final void setPriority(int a)
参数
a : 将此线程设置为优先级。
返回
它不返回任何值。
异常
IllegalArgumentException: 如果优先级不是，则抛出此异常。
SecurityException: 如果当前线程无法修改此线程，则抛出此异常。
示例1: 最大优先级线程
public class JavaSetPriorityExp1 extends Thread
{
public void run()
{
System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());
}
public static void main(String args[])
{
// creating one thread
JavaSetPriorityExp1 t1=new JavaSetPriorityExp1();
// print the maximum priority of this thread
t1.setPriority(Thread.MAX_PRIORITY);
// call the run() method
t1.start();
}
}
输出:
Priority of thread is: 10
示例2: 最低优先级线程
public class JavaSetPriorityExp2 extends Thread
{
public void run()
{
System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());
}
public static void main(String args[])
{
// creating one thread
JavaSetPriorityExp2 t1=new JavaSetPriorityExp2();
// print the minimum priority of this thread
t1.setPriority(Thread.MIN_PRIORITY);
// this will call the run() method
t1.start();
}
}
输出:
示例3: 普通优先级线程
public class JavaSetPriorityExp3 extends Thread
{
public void run()
{
System.out.println("Priority of thread is: "+Thread.currentThread().getPriority());
}
public static void main(String args[])
{
// creating one thread
JavaSetPriorityExp3 t1=new JavaSetPriorityExp3();
// print the normal priority of this thread
t1.setPriority(Thread.NORM_PRIORITY);
// starting the thread
t1.start();
}
}
输出:
示例4: 用户定义优先级线程
public class JavaSetPriorityExp4 extends Thread
{
public void run()
{
System.out.println("running...");
}
public static void main(String args[])
{
// creating one thread
JavaSetPriorityExp4 t1=new JavaSetPriorityExp4();
JavaSetPriorityExp4 t2=new JavaSetPriorityExp4();
// set the priority
t1.setPriority(4);
t2.setPriority(7);
// print the user defined priority
System.out.println("Priority of thread t1 is: " + t1.getPriority());
//4
System.out.println("Priority of thread t2 is: " + t2.getPriority());
//7
// this will call the run() method
t1.start();
}
}
输出:
Priority of thread t1 is: 4
Priority of thread t2 is: 7
running...
示例5: 优先级大于10
public class JavaSetPriorityExp5 extends Thread
{
public void run()
{
System.out.println("running...");
}
public static void main(String args[])
{
// creating one thread
JavaSetPriorityExp5 t1=new JavaSetPriorityExp5();
JavaSetPriorityExp5 t2=new JavaSetPriorityExp5();
// set the priority
t1.setPriority(12);
t2.setPriority(7);
// print exception because priority of t1 is greater than 10
System.out.println("Priority of thread t1 is: " + t1.getPriority());
System.out.println("Priority of thread t2 is: " + t2.getPriority());
// call the run() method
t1.start();
}
}
输出:
Exception in thread "main" java.lang.IllegalArgumentException
at java.lang.Thread.setPriority(Thread.java:1089)
at JavaSetPriorityExp5.main(JavaSetPriorityExp5.java:13)
