try-catch

问题 This question already has answers here : try/catch with InputMismatchException creates infinite loop (7 answers) Closed 4 years ago . I keep getting my code caught in an infinite while loop. It is nothing to advanced, but i can not figure it out for the life of me! Someone Please help I have purplosely just re created the specific error without all of the if statements i have in my actual program. package bs; import java.util.InputMismatchException; import java.util.Scanner; public class bs {

问题 I want to throw my own exceptions with the base class Exception . There is a virtual method print which will be overwritten by the subclasses. I only catch the type Exception& and use print to get the specific error. The problem is that once I throw a reference of a subclass it is trated as if it were the base class. Here is an example: #include <iostream> using namespace std; class Exception { public: virtual void print() { cout << "Exception" << endl; } }; class IllegalArgumentException :

问题 I heard such an opinion that you should avoid usage of try/catch at all because it takes many resources. So could promise error handling could be faster? Or it does not matter at all? function f(somethingDangerous) { return new Promise((resolve, reject) => { // try { // somethingDangerous(); // resolve(); // } catch (err) { // reject(err); // } // VS somethingDangerous(); resolve(); }).catch((err) => { console.error('Catched: ' + err); }); } f(() => {throw 'DANGEROUS THING';}); UPD : I know

问题 Someone in a different question suggested using catch(...) to capture all otherwise unhandled - unexpected/unforseen exceptions by surrounding the whole main() with the try{}catch(...){} block. It sounds like an interesting idea that could save a lot of time debugging the program and leave at least a hint of what happened. The essence of the question is what information can be recovered that way (other than whatever debug globals I leave behind), and how to recover it (how to access and

问题 How would one go about checking to see if a method exists for a class in Java? Would a try {...} catch {...} statement be good practice? 回答1: I assume that you want to check the method doSomething(String, Object) . You might try this: boolean methodExists = false; try { obj.doSomething("", null); methodExists = true; } catch (NoSuchMethodError e) { // ignore } This will not work, since the method will be resolved at compile-time. You really need to use reflection for it. And if you have

问题 Something I've always been curious of public class FileDataValidator { private String[] lineData; public FileDataValidator(String[] lineData){ this.lineData = lineData; removeLeadingAndTrailingQuotes(); try { validateName(); validateAge(); validateTown(); } catch(InvalidFormatException e) { e.printStackTrace(); } } //validation methods below all throwing InvalidFormatException Is is not advisable to include the try/catch block within my Constructor? I know I could have the Constructor throw

问题 Something I've always been curious of public class FileDataValidator { private String[] lineData; public FileDataValidator(String[] lineData){ this.lineData = lineData; removeLeadingAndTrailingQuotes(); try { validateName(); validateAge(); validateTown(); } catch(InvalidFormatException e) { e.printStackTrace(); } } //validation methods below all throwing InvalidFormatException Is is not advisable to include the try/catch block within my Constructor? I know I could have the Constructor throw

问题 One of the things that always bugs me about using Readers and Streams in Java is that the close() method can throw an exception. Since it's a good idea to put the close method in a finally block, that necessitates a bit of an awkward situation. I usually use this construction: FileReader fr = new FileReader("SomeFile.txt"); try { try { fr.read(); } finally { fr.close(); } } catch(Exception e) { // Do exception handling } But I've also seen this construction: FileReader fr = new FileReader(

问题 Mentally, I've always wondered how try/throw/catch looks behind the scenes, when the C++ compiles translates it to assembler. But since I never use it, I never got around to checking it out (some people would say lazy). Is the normal stack used for keeping track of try s, or is a separate per-thread stack kept for this purpose alone? Is the implementation between MSVC and g++ big or small? Please show me some pseudo asm (IA-32 is ok too) so I never have to check it out myself! :) Edit: Now I

问题 Perhaps I misunderstood how catching errors with async/await is supposed to work from things articles like this https://jakearchibald.com/2014/es7-async-functions/ and this http://pouchdb.com/2015/03/05/taming-the-async-beast-with-es7.html, but my catch block is not catching 400/500. async () => { let response try { let response = await fetch('not-a-real-url') } catch (err) { // not jumping in here. console.log(err) } }() example on codepen if it helps 回答1: 400/500 is not an error, it's a