Rethowing Exception

Rethowing Excetpion

在catch的block中可以使用throw继续向上抛，会忽略以后的catch块儿，不会捕获已捕捉的这个Exception。

在这种情况下，在更高的调用的时候捕获到的exception还是原来的，但是有两种情况可以改变exception的来源:1.调用e.fillInStackTrace() 2.使用throw，但是抛的是不同的exception

package com.skyon;

public class Rethrowing {
public static void f() throws Exception {
System.out.println("originating the exception in f()");
throw new Exception("throw from f()");
}

public static void g() throws Exception{
try{
f();
}catch(Exception e){
System.out.println("Inside g(), e.printStackTrace()");
e.printStackTrace();
throw e;
}
}
public static void h() throws Exception{
try{
f();
}catch(Exception e){
System.out.println("Inside h(), e.printStackTrace()");
e.printStackTrace(System.out);
throw (Exception) e.fillInStackTrace();
}
}

public static void main(String[] args) {
try{
g();
}catch(Exception e){
System.out.println("main : printStackTrace()");
e.printStackTrace(System.out);
}
try{
h();
}catch(Exception e){
e.printStackTrace();
}
}

}

>>>输出:
originating the exception in f()
java.lang.Exception: throw from f()
at com.skyon.Rethrowing.f(Rethrowing.java:6)
at com.skyon.Rethrowing.g(Rethrowing.java:11)
at com.skyon.Rethrowing.main(Rethrowing.java:30)
Inside g(), e.printStackTrace()
main : printStackTrace()
java.lang.Exception: throw from f()
at com.skyon.Rethrowing.f(Rethrowing.java:6)
at com.skyon.Rethrowing.g(Rethrowing.java:11)
at com.skyon.Rethrowing.main(Rethrowing.java:30)
originating the exception in f()
Inside h(), e.printStackTrace()
java.lang.Exception: throw from f()
at com.skyon.Rethrowing.f(Rethrowing.java:6)
at com.skyon.Rethrowing.h(Rethrowing.java:20)
at com.skyon.Rethrowing.main(Rethrowing.java:36)
java.lang.Exception: throw from f()
at com.skyon.Rethrowing.h(Rethrowing.java:24)
at com.skyon.Rethrowing.main(Rethrowing.java:36)