将“受检查异常”转化为“不受检查异常”

为了简化“受检查异常”的处理工作，可以将其包装成为“不受检查异常”，这样就不必捕获它，或者在异常声明中列出。注意，这样抛出的异常就是一个新的封装了原受检查异常的异常了。如果程序员确切知道会发生该异常，则可以对其进行捕获，并利用getCause()获取原“受检查异常”并再对其进行处理。再次捕获进catch块中的时候，编译器强制用Throwable作为“保底”

//IgnoreRuntimeException.java
//Transform a compile-checked exception into a Runtime Exception

package com.msn.spaces.bryantd001;

class CheckedWhenCompliedException extends Exception{
      private String str;

     CheckedWhenCompliedException(){
           super("Compile-checked Exception");
           str = "Compile-checked Exception --> Runtime Exception";
     }

     public void throwRuntimeException(){
           System.out.println("I will be transformed into a Runtime Exception and be rethrown.");
           throw new RuntimeException(this);
     }

     public String toString(){
           return str;
     }
}

public class IgnoreRuntimeException{
      public static void main(String[] args){
            try{
                  CheckedWhenCompliedException e = new CheckedWhenCompliedException();
                  e.throwRuntimeException();
           }catch(RuntimeException re){
                 try{
                       throw re.getCause();
                 }catch(CheckedWhenCompliedException e){
                       System.out.println(e);
                 }catch(Throwable e){   //编译器强制异常基类
                       System.out.println(e);
                 }
           }
      }
}