白话Java - try-finally块

本文讲述的是Java中try finally代码块执行顺序,和当其存在于循环中的时候的跳出和执行问题。白话,也要简化,一段代码,来说明问题

  /**
	 * @author lihzh
	 * @date 2012-6-8 下午9:21:22
	 * @blog http://www.coderli.com
	 */
	public static void main(String[] args) {
		for (int i = 0; i < 10; i++) {
			System.out.println("Begin loop: " + i);
			if (i == 2) {
				System.out.println("Continue: " + i);
				continue;
			}
			try {
				System.out.println("i = " + i);
				if (i == 4) {
					System.out.println("In try continue: " + i);
					continue;
				}
				if (i == 5) {
					return;
				}
			} finally {
				System.out.println("This is finally. " + i);
			}
		}
	}

执行结果:

Begin loop: 0
i = 0
This is finally. 0
Begin loop: 1
i = 1
This is finally. 1
Begin loop: 2
Continue: 2
Begin loop: 3
i = 3
This is finally. 3
Begin loop: 4
i = 4
In try continue: 4
This is finally. 4
Begin loop: 5
i = 5
This is finally. 5

如果还没看明白,那我再啰嗦两句:finally就是最后的,跟trycatch是兄弟,就好像正常人走try分支,走着走着你不正常了,就开始走catch分支,但是不管你正常不正常,最后都要通过最终的检测,才算完。他们是一个组合。至于外面的for循环,就好像你在跑圈,本来每圈你都路过这个关卡(try-finnaly),但是你说,第二圈(i=2)跑一半的时候,突然说,下面我不跑了,我要开始跑第三圈,那关卡也拿你没辙。拦不住你。至于跑到第五圈了,你说不行了,我跑不动了,以后都不跑了,那也行你退出了,不过你已经进入关卡了,一样,唯一的出口就在finally。通过再退出。

Thanks a lot.