try-catch

问题 This question already has answers here : Async exception handling with void (2 answers) Closed 2 years ago . short version, this method: public override async void MethodWithException() { throw new Exception("any EXCEPTION type and format will be skipped by outer try-catch block"); } is not caught by this block ("catch" is skipped): try { realClassFromAbstractObject.MethodWithException(); Console.WriteLine("Output in the console – NOT POSSIBLE but true!"); } catch (Exception exception) { /

问题 I am currently trying make my custom compiler allow using try/catch as an expression, i.e. leaving a value on the stack. The type checker and the backend already support this, but the problem seems to be ASM's COMPUTE_FRAMES . With the below code for instrumentation: private void write(MethodWriter writer, boolean expression) { org.objectweb.asm.Label tryStart = new org.objectweb.asm.Label(); org.objectweb.asm.Label tryEnd = new org.objectweb.asm.Label(); org.objectweb.asm.Label endLabel =

问题 Charset charset = Charset.forName("US-ASCII"); try (BufferedReader reader = Files.newBufferedReader(file, charset)) { String line = null; while ((line = reader.readLine()) != null) { System.out.println(line); } } catch (IOException x) { System.err.format("IOException: %s%n", x); } I saw such a piece of code on The Java Tutorials, in which a bracket statement is after key word 'try'. Is this valid? why cannot eclipse recognize it and report syntax error? 回答1: It is the Java 7's try with

问题 I am currently facing this problem. Analyzing a big data-set (roughly 3 million observations), I need to convert a variable from a format to another. Specifically, I had the date of incorporation of several firms, but coming in two formats: YYYY or MM-DD-YYYY , or other possibilities of which the last 4 characters were always relative to the year. What I need is just the year so I developed this code: library(stringi) for (i in 1:length(amadeus$Dateofincorporation) { if(nchar(amadeus

问题 I have a scheduled SSIS package with a script task in SQL Server Agent on our server. I did set the timeout for the SQL connection, and for some of the codes inside the Try block, it will throw the error, and there is MessageBox.Show inside the Catch block. If I leave the codes as they are, it will fail the job, but if I comment out those MessageBox.Show and leave the Catch block blank just for testing purpose, the job ran successfully. Anybody knows that the MessageBox.Show will affect the

问题 What is the convention for Try/Catch outside of obviously needed locations(such as getting specific user input)? While code re-use is an important idea behind OOP, is it expected that each (example) array access should have a try/catch? Is it primarily the designer's decision of what can throw an exception, and those parts of the program that should be well regulated enough to never throw an exception? Ex. An array of playing cards is, and should always be, 52 cards. No try/catch is necessary

问题 I am pretty new to using object/classes in PHP and I am curious about EXCEPTIONS , TRY , and CATCH In the example below I have all 3 shown in use. Obviously an exception is some sort of way of triggering an error but I do not understand why? In the code below I could easily show some sort of error or something without the exception part there? Below that example is an example using try and catch. It appears to me to be the same as using if/else. I may be wrong, this is just the way I see them

问题 What are your thoughts on code that looks like this: public void doSomething() { try { // actual code goes here } catch (Exception ex) { throw; } } The problem I see is the actual error is not handled, just throwing the exception in a different place. I find it more difficult to debug because i don't get a line number where the actual problem is. So my question is why would this be good? ---- EDIT ---- From the answers it looks like most people are saying it's pointless to do this with no

问题 Which is better for finally block: finally { try { con.close(); stat.close(); } catch (SQLException sqlee) { sqlee.printStackTrace(); } } Or: finally { try { if (con != null) { con.close(); } if (stat != null) { stat.close(); } } catch (SQLException sqlee) { sqlee.printStackTrace(); } } 回答1: Better way to use is the 2nd one, because if an exception is thrown while initializing con or stat , they won't be initialized, and might be left initialized to null . In that case, using the 1st code

问题 I have a list of Vector2's Generated I have to check against a dictionary to see if they exist, this function gets executed every tick. which would run fastest/ be better to do it this way? public static bool exists(Vector2 Position, Dictionary<Vector2, object> ToCheck) { try { object Test = ToCheck[Position]; return (true); } catch { return (false); } } Or should I stick with The norm ? public static bool exists(Vector2 Position, Dictionary<Vector2, object> ToCheck) { if (ToCheck.ContainsKey