Java 没有线程实例的线程方法调用
为什么该类在第11行编译时没有错误,以及如何解释最后一行输出:Java 没有线程实例的线程方法调用,java,multithreading,Java,Multithreading,为什么该类在第11行编译时没有错误,以及如何解释最后一行输出: class Bang extends Thread { static Thread t1; public static void main(String[] args) throws Exception { System.out.println("main thread ID = " + Thread.currentThread().getId()); t1 = new Threa
class Bang extends Thread {
static Thread t1;
public static void main(String[] args) throws Exception {
System.out.println("main thread ID = " + Thread.currentThread().getId());
t1 = new Thread(new Bang());
t1.setPriority(7);
t1.setName("T1");
t1.start();
}
public void run() {
Thread th = Thread.currentThread();
System.out.println(th.getId() + " " + th.getName() + " "
+ th.getPriority() + " " + th.toString() + "\n");
System.out.println(getId() + " " + getName() + " " + getPriority()
+ " " + toString());
}
}
输出:
主螺纹ID=1
9 T1 7螺纹[T1,7,主螺纹]
8螺纹-0 5螺纹[螺纹-0,5,主螺纹]
谢谢,@Tunaki很合适。我只想补充一下他说的话 总共有三个线程对象
run
方法中打印的内容正在线程T1上运行
Thread.currentThread().getId()
将返回运行线程的idT1,即9
this.getId()
将返回Bang对象的id,该对象为8。记住,您在T1对象之前创建了Bang对象?这就是为什么Bang具有较小的id8,而T1具有较高的threadId9
希望这有帮助。我已经更新了您的代码,以打印有关hashcode和类详细信息的更多信息。输出应给出清晰的图像
代码:
输出
因为
扩展了线程
。您希望出现什么错误?In-line System.out.println(getId+..);,因为实例方法a调用时没有实例,或者如果是隐式的,那么是什么?哪个线程的id=8?谢谢,太好了!非常感谢你!如果这完全回答了你的问题,你可以接受这个答案。
class Bang extends Thread {
static Thread t1;
public static void main(String[] args) throws Exception {
System.out.println("main thread ID = " + Thread.currentThread().getId());
Bang bang = new Bang(); //Creating a local variable so we can print the object details.
t1 = new Thread(bang);
t1.setPriority(7);
t1.setName("T1");
threadInfo(bang);
threadInfo(t1);
t1.start();
}
public void run() {
threadInfo(this);
}
public static void threadInfo(Thread argThreadObject) {
System.out.println("===================================");
Thread currentThreadObject = Thread.currentThread();
printThreadInfo("currentThreadObject", currentThreadObject);
printThreadInfo("argThreadObject", argThreadObject);
System.out.println("===================================");
}
public static void printThreadInfo(String threadObjId, Thread threadObject) {
System.out.println(
threadObjId + ": "
+ threadObject.getId() + ":"
+ threadObject.getName() + ":"
+ threadObject.getPriority() + ":"
+ threadObject.toString() + " instanceId: "
+ threadObject.hashCode() + "@"
+ threadObject.getClass().getName());
}
}
main thread ID = 1
===================================
currentThreadObject: 1:main:5:Thread[main,5,main] instanceId: 1113847530@java.lang.Thread
argThreadObject: 9:T1:7:Thread[T1,7,main] instanceId: 820485811@java.lang.Thread
===================================
===================================
currentThreadObject: 1:main:5:Thread[main,5,main] instanceId: 1113847530@java.lang.Thread
argThreadObject: 8:Thread-0:5:Thread[Thread-0,5,main] instanceId: 912528090@Bang
===================================
===================================
currentThreadObject: 9:T1:7:Thread[T1,7,main] instanceId: 820485811@java.lang.Thread
argThreadObject: 8:Thread-0:5:Thread[Thread-0,5,main] instanceId: 912528090@Bang
===================================