java 七中再谈try catch

java 7中再谈try catch

 看输出：
   Doing: Writing an article
Exception Message: Exception occured while doing work Exception Type: javaapplication4.ExceptionA
Closing the resource
Exception Message: Exception occured while closing Exception Type: javaapplication4.ExceptionB

再来看java 7中的新写法，代码如下：


 输出结果为：
  Listening to podcast
Res1 closing
Exception: Exception thrown while doing some work Thrown by: ExceptionA

 大家可以思考下为什么这样输出，在新特性中，资源的自动关闭调用了close(),而
NewResource res = new NewResource("Res1 closing")){
已经为closingMessage赋值了，而最后的Exception e是输出了，suprred掉了
exception a和exception b的输出。

再看一个多层嵌套的try catch例子
  

 输出：
  Wow res getting res to do work
Nestedres closing
Res2 closing
Res1 closing
Exception: Exception thrown while doing some work Thrown by: ExceptionA

 可以看到，后声明的资源上被最先CLOSE掉的，这里各自原先的exception都被supressed掉了。还可以用e.getSuppressed() 把屏蔽掉的exception都放来，比如
 


 输出显示：
Wow res getting res to do work
Nestedres closing
Res2 closing
Res1 closing
Exception: Exception thrown while doing some work Thrown by: ExceptionA
Exception thrown while closing Class: ExceptionB
Exception thrown while closing Class: ExceptionB
Exception thrown while closing Class: ExceptionB