Java：如何使用Thread.join
我是线程的新手。 我如何让t.join工作，调用它的线程等到t执行t.join ？
这段代码只会冻结程序，因为线程正在等待自己死掉，对吧？
public static void main(String[] args) throws InterruptedException { Thread t0 = new Thready(); t0.start(); } @Override public void run() { for (String s : info) { try { join(); Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.printf("%s %s%n", getName(), s); } }
如果我想要两个线程，我会怎么做，其中一个打印出info数组的一半，然后在完成其余操作之前等待另一个完成？
使用这样的东西：
public void executeMultiThread(int numThreads) throws Exception { List threads = new ArrayList(); for (int i = 0; i < numThreads; i++) { Thread t = new Thread(new Runnable() { public void run() { // do your work } }); // System.out.println("STARTING: " + t); t.start(); threads.add(t); } for (int i = 0; i < threads.size(); i++) { // Big number to wait so this can be debugged // System.out.println("JOINING: " + threads.get(i)); ((Thread)threads.get(i)).join(1000000); }
如果otherThread是另一个线程，你可以这样做：
@Override public void run() { int i = 0; int half = (info.size() / 2); for (String s : info) { i++; if (i == half) { try { otherThread.join(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.printf("%s %s%n", getName(), s); Thread.yield(); //Give other threads a chance to do their work } }
Sun的Java教程： http ： //java.sun.com/docs/books/tutorial/essential/concurrency/join.html
你必须在另一个Thread上调用join方法。
就像是：
@Override public void run() { String[] info = new String[] {"abc", "def", "ghi", "jkl"}; Thread other = new OtherThread(); other.start(); for (int i = 0; i < info.length; i++) { try { if (i == info.length / 2) { other.join(); // wait for other to terminate } Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.printf("%s %s%n", getName(), info[i]); } }