线程有多种写法。
第一种是实现runnable接口。
第二种是继承thread类。
第三种是直接写runnable的实现方法。
public class ThreadTest {
public static void main (String[] args) {
Runnable r = new Runnable() {
public void run() {
System.out.print("foo");
}
};
Thread t = new Thread(r);
t.run(); //output foo
t.start(); //output foo
try {
t.join(); //waiting for thread end
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
Thread t1 = new Thread(r);
t1.start(); //output foo
t1.run(); //nothing output.because target(runnable is null).
}
}
如果调用两次start方法会有什么效果呢？
Thread t1 = new Thread(r); t1.start(); //output foo t1.start(); //threadStatus != 0(NEW) throw a IllegalThreadStateException