Java：Try/Catch 语句：捕获异常时，重复 try 语句？
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Java: Try/Catch Statements: While exception is caught, repeat try statements?
提问by
Is there any way to do this?
有没有办法做到这一点？
//Example function taking in first and last name and returning the last name.
public void lastNameGenerator() throws Exception{
try {
String fullName = JOptionPane.showInputDialog("Enter your full name");
String lastName = fullName.split("\s+")[1];
catch (IOException e) {
System.out.println("Sorry, please enter your full name separated by a space.")
//Repeat try statement. ie. Ask user for a new string?
}
System.out.println(lastName);
I think I can use scanner for this instead, but I was just curious about if there was a way to repeat the try statement after catching an exception.
我想我可以为此使用扫描仪，但我只是想知道是否有办法在捕获异常后重复 try 语句。
采纳答案by Suresh Atta
Something like this ?
像这样的东西？
while(condition){
try{
} catch(Exception e) { // or your specific exception
}
}
回答by Mohayemin
You need a recursion
你需要一个递归
public void lastNameGenerator(){
try {
String fullName = JOptionPane.showInputDialog("Enter your full name");
String lastName = fullname.split("\s+")[1];
catch (IOException e) {
System.out.println("Sorry, please enter your full name separated by a space.")
lastNameGenerator();
}
System.out.println(lastName);
}
回答by Micha? Tabor
Just put try..catch inside while loop.
只需将 try..catch 放入 while 循环中。
回答by M K
One way is to use a while loop and exit when the name has been set properly.
一种方法是使用 while 循环并在正确设置名称后退出。
boolean success = false;
while (!success) {
try {
// do stuff
success = true;
} catch (IOException e) {
}
}
回答by Andreas Dolk
There is no "re-try" in the language, like others suggested already: create an outer while loop and set a flag in the "catch" block that triggers the retry (and a clear the flag after a successful try)
语言中没有“重试”，就像其他人已经建议的那样：创建一个外部 while 循环并在触发重试的“catch”块中设置一个标志（并在成功尝试后清除标志）
回答by Axel
This sure is a simplified code fragment because in this case I'd simply remove the try/catchaltogether - IOException is never thrown. You could get an IndexOutOfBoundsException, but in your example it really shouldn't be handled with exceptions.
这肯定是一个简化的代码片段，因为在这种情况下，我会简单地完全删除try/catch- IOException 永远不会被抛出。你可以得到IndexOutOfBoundsException，但在你的例子中，它真的不应该用异常处理。
public void lastNameGenerator(){
String[] nameParts;
do {
String fullName = JOptionPane.showInputDialog("Enter your full name");
nameParts = fullName != null ? fullName.split("\s+") : null;
} while (nameParts!=null && nameParts.length<2);
String lastName = nameParts[1];
System.out.println(lastName);
}
EDIT: JOptionPane.showInputDialogmight return nullwhich wasn't handled before. Also fixed some typos.
编辑：JOptionPane.showInputDialog可能会返回null以前没有处理过的。还修正了一些错别字。
回答by Aniket Thakur
Signature of showInputDialog() is
showInputDialog() 的签名是
public static java.lang.String showInputDialog(java.lang.Object message)
throws java.awt.HeadlessException
and that of split() is
而 split() 是
public java.lang.String[] split(java.lang.String regex)
None of then throw IOException. Then how are you catching it?
没有然后扔IOException。那你怎么抓？
Anyway possible solution to your problem would be
无论如何，您的问题的可能解决方案是
public void lastNameGenerator(){
String fullName = null;
while((fullName = JOptionPane.showInputDialog("Enter your full name")).split("\s+").length<2) {
}
String lastName = fullName.split("\s+")[1];
System.out.println(lastName);
}
No need of try-catch. tried it myself. It works fine.
无需尝试捕获。我自己试过了。它工作正常。
回答by Johnny
Would it be ok to use external lib?
使用外部库可以吗？
If so, check out Failsafe.
如果是这样，请查看Failsafe。
First, you define a RetryPolicy that expresses when retries should be performed:
首先，您定义一个 RetryPolicy 来表示应该何时执行重试：
RetryPolicy retryPolicy = new RetryPolicy()
.retryOn(IOException.class)
.withMaxRetries(5)
.withMaxDuration(pollDurationSec, TimeUnit.SECONDS);
Then, you use your RetryPolicy to execute a Runnable or Callable with retries:
然后，您使用 RetryPolicy 重试执行 Runnable 或 Callable：
Failsafe.with(retryPolicy)
.onRetry((r, f) -> fixScannerIssue())
.run(() -> scannerStatement());
回答by bnsd55
You can use https://github.com/bnsd55/RetryCatch
您可以使用https://github.com/bnsd55/RetryCatch
Example:
例子：
RetryCatch retryCatchSyncRunnable = new RetryCatch();
retryCatchSyncRunnable
// For infinite retry times, just remove this row
.retryCount(3)
// For retrying on all exceptions, just remove this row
.retryOn(ArithmeticException.class, IndexOutOfBoundsException.class)
.onSuccess(() -> System.out.println("Success, There is no result because this is a runnable."))
.onRetry((retryCount, e) -> System.out.println("Retry count: " + retryCount + ", Exception message: " + e.getMessage()))
.onFailure(e -> System.out.println("Failure: Exception message: " + e.getMessage()))
.run(new ExampleRunnable());
Instead of new ExampleRunnable()you can pass your own anonymous function.
而不是new ExampleRunnable()你可以传递你自己的匿名函数。
