Java异常处理机制以及try(2)

四，try-catch-finally-return执行顺序：

1，try-catch-finally执行顺序：

①，执行try{}块

②，如果try{}块有异常产生，执行catch{}块

③，无论有没有异常都要执行finally{}块，这里可以看出只要finally中有return，必然返回finally{}中的return

2,return的执行，

①，如果finally{}块中有return语句，只执行finally{}块中的return语句

②，如果finally{}块中没有return语句，如果try{}有异常，则返回catch{}中的return语句，不然执行try{}中return语句

在这种情况下，return语句块是在finally{}之后执行

finally{}中有return：

①如果try正常/或异常，则执行finally{}中的return

package com.testJava.Exception;
public class TryCatchfFinally {
public static void main(String[] args){
TryCatchfFinally tcf = new TryCatchfFinally();
System.out.println(tcf.testException());
}
public  String testException(){
try {
System.out.println("start try");
int[] a= {2};
for(int i=0 ; i<1;i++){//i=2①
System.out.println(a[i]);
}
System.out.println("try end");
return "return of try not finally";
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("arrayIndexOutOfBoundsException");
return "return in catch arrayIndexOutOfBoundsException";
}catch(NullPointerException e){

System.out.println("nullPointerException");
return "return in catch";

}finally{
System.out.println("finally start try");
int[] a= {2};
for(int i=0 ; i<1;i++){//i=2②
System.out.println(a[i]);
}
System.out.println("finallyend end  end");

System.out.println("finally");

return "return of finally";
}
}
}

①处i=1运行结果:

start try
2
try end
finally start try
2
finallyend end  end
finally
return of finally

①处i=2运行结果：

start try
2
arrayIndexOutOfBoundsException
finally start try
2
finallyend end  end
finally
return of finally