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[英]Nested try-catch IOException inside catch for FileNotFoundException
[英]try-catch doesn't catch IOException
在下面的代码中,我获得了Unreachable catch block for IOException
的Unreachable catch block for IOException
。 永远不会从try语句体错误(带下划线)抛出此异常,其中IOException
位于} catch (IOException e){
我做错了什么?
class driver {
public static void main(String[] args) {
// TODO Auto-generated method stub
Customer forrest = new Customer("Forrest Gump", 1,
"42 New Street, New York, New York");
Customer random = new Customer("Random Name", 2,
"44 New Street, New York, New York");
Customer customer[] = { null, forrest, random };
int whichOption = 1;
int id = 0;
char action = ' ';
char accSrc = ' ';
char accDest = ' ';
double amount = 0;
BankAccount src = null;
do {
try{
// process JOptionPane input information
String input = JOptionPane
.showInputDialog("Please enter your transaction information: ");
Scanner s = new Scanner(input);
id = Integer.parseInt(s.next());
action = Character.toUpperCase((s.next().charAt(0)));
if (action == 'T') {
amount = s.nextDouble();
accSrc = s.next().charAt(0);
accDest = s.next().charAt(0);
} else if (action == 'G' || action == 'I') {
accSrc = s.next().charAt(0);
} else {
// if D,W
amount = s.nextDouble();
accSrc = s.next().charAt(0);
}
} catch (IOException e){
}
// taking action accordingly (T)ransfer, (D)eposit, (W)ithdraw, (I)nterest
if (action == 'T') {
(customer[id].getAccount(accSrc)).transfer(amount,
customer[id].getAccount(accDest));
} else if (action == 'G') {
System.out.println("The current balance on your " + accSrc
+ " account is "
+ customer[id].getAccount(accSrc).getBalance() + "\n");
} else if (action == 'D') {
(customer[id].getAccount(accSrc)).deposit(amount);
} else if (action == 'W') {
(customer[id].getAccount(accSrc)).withdraw(amount);
} else if (action == 'I') {
(customer[id].getAccount(accSrc)).computeInterest();
}
whichOption = JOptionPane
.showConfirmDialog(null , "Do you want to continue?");
System.out.println("The balance on " + customer[id].getName()
+ " auto account is " + customer[id].A.balance);
System.out.println("The balance on " + customer[id].getName()
+ " savings account is " + customer[id].S.balance);
System.out.println("The balance on " + customer[id].getName()
+ " checkings account is " + customer[id].C.balance);
System.out.println("The balance on " + customer[id].getName()
+ " loan account is " + customer[id].L.balance + "\n");
} while (whichOption == 0);
}
}
这是因为你在try/catch
执行的操作都没有抛出IOException。
根据Scanner javadoc
大多数Scanner类方法抛出FileNotFoundException
(由于不从文件中读取,因此不适用于您的情况)(或) IllegalArgumentException
(或) IllegalStateException
您需要将IOException
更改为上述任一异常(或)删除try / catch。
您可以删除IOException和try catch,因为try catch中的所有语句都不会抛出此异常
在try
块中抛出IOException
似乎没什么
在try块中没有方法调用抛出IOException
,这就是catch是无法访问的代码的原因。
您可以安全地删除try和catch,因为这种情况永远不会发生。
你的catch
块是空的,表明你无论如何都不会真正处理异常。 你可能在那里有一些代码让你抓住它,但现在你已经没有它了。 只需删除整个周围的try-catch
,就不会有其他问题。
try/catch
块为空,代码不会抛出IOException
但它可能抛出其他异常。
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