Java异常处理中finally中的return会覆盖catch语句中的return语句

Java异常处理中finally中的return会覆盖catch语句中的return语句和throw语句,所以Java不建议在finally中使用return语句

此外 finally中的throw语句也会覆盖catch语句中的return语句和throw语句

程序实例如下:(本代码来源于CSDN某大神:http://blog.csdn.net/hguisu/article/details/6155636   在此表示感谢)

package Test;  
  
public class TestException {  
    public TestException() {  
    }  
  
    boolean testEx() throws Exception {  
        boolean ret = true;  
        try {  
            ret = testEx1();  
        } catch (Exception e) {  
            System.out.println("testEx, catch exception");  
            ret = false;  
            throw e;  
        } finally {  
            System.out.println("testEx, finally; return value=" + ret);  
            return ret;  
        }  
    }  
  
    boolean testEx1() throws Exception {  
        boolean ret = true;  
        try {  
            ret = testEx2();  
            if (!ret) {  
                return false;  
            }  
            System.out.println("testEx1, at the end of try");  
            return ret;  
        } catch (Exception e) {  
            System.out.println("testEx1, catch exception");  
            ret = false;  
            throw e;  
        } finally {  
            System.out.println("testEx1, finally; return value=" + ret);  
            return ret;  
        }  
    }  
  
    boolean testEx2() throws Exception {  
        boolean ret = true;  
        try {  
            int b = 12;  
            int c;  
            for (int i = 2; i >= -2; i--) {  
                c = b / i;  
                System.out.println("i=" + i);  
            }  
            return true;  
        } catch (Exception e) {  
            System.out.println("testEx2, catch exception");  
           ret = false;  
            throw e;  
        } finally {  
            System.out.println("testEx2, finally; return value=" + ret);  
            return ret;  
        }  
    }  
      public static void main(String[] args) {  
        TestException testException1 = new TestException();  
        try {  
            testException1.testEx();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
}  

输出结果为:

i=2
i=1
testEx2, catch exception
testEx2, finally; return value=false
testEx1, finally; return value=false
testEx, finally; return value=false

 

 

 

此外:

finally块的语句在try或catch中的return语句执行之后返回之前执行且finally里的修改语句不能影响try或catch中 return已经确定的返回值(如果catch语句中返回的是一个引用,那么在finally语句中对引用的内容进行修改是会影响catch中return的返回值的,若finally里也有return语句则覆盖try或catch中的return语句直接返回。

 

posted @ 2016-07-28 21:43  青儿哥哥  阅读(2488)  评论(0编辑  收藏  举报