finally

Try except finally raise

由 僤鯓⒐⒋嵵緔 提交于 2020-01-21 19:38:24
try : # int('qwe') f = open ( '我为什么是一个文件.txt' , 'w' ) print ( f . write ( '我存在了!!!' ) ) sum = 1 + '1' f . close ( ) #except OSError as reason: # print('文件出错\n错误的原因是: '+str(reason)) #except TypeError as reason: # print('类型出错\n错误的原因是: '+str(reason)) #except TypeError as reason: # print('类型出错\n错误的原因是: '+str(reason)) except ( OSError , TypeError ) : print ( '出错了' ) finally : f . close ( ) finally 无论如何都会执行 来源： CSDN 作者： 韩凯 dragon in sky 链接： https://blog.csdn.net/hk2121/article/details/104064589

从字节码看try catch finally的return如何执行

由 时间秒杀一切 提交于 2020-01-16 20:57:44
文章是对两位博主的总结，提炼，原文如下链接： 从字节码看try catch finally的return如何执行 Java中try catch finally语句中含有return语句的执行情况（总结版） 测试代码很简单，如下： Test.java public class Test { public int get ( ) { try { return 0 ; } catch ( Exception e ) { e . printStackTrace ( ) ; return 1 ; } finally { return 2 ; } } } 执行$ javap -verbose Test.class $ javap - verbose Test . class Classfile / E : / workspace / java / Test . class Last modified 2018 - 1 - 29 ; size 405 bytes MD5 checksum f8f6002de3931b2e95125679f2ce1f6c Compiled from "Test.java" public class Test minor version : 0 major version : 52 flags : ACC_PUBLIC , ACC_SUPER Constant

异常与抛出

由 我的梦境 提交于 2020-01-16 04:34:56
1. 请阅读并运行 AboutException.java 示例，然后通过后面的几页 PPT 了解 Java 中实现异常处理的基础知识。 Java 中的异常捕获语句 Try{ // 可能发生运行错误的代码； } catch （异常类型 异常对象引用） { // 用于处理异常的代码 } finally{ // 用于“善后” 的代码 } Java 中所有可捕获的异常都派生自 Exception 类，把可能会发生错误的代码放进 try 语句块中，当程序检测到出现了一个错误时会抛出一个异常对象。异常处理代码会捕获并处理这个错误， catch 语句块中的代码用于处理错误。当异常发生时，程序控制流程由 try 语句块跳转到 catch 语句块。不管是否有异常发生， finally 语句块中的语句始终保证被执行。如果没有提供合适的异常处理代码， JVM 将会结束掉整个应用程序。 2. 阅读以下代码（ CatchWho.java ），写出程序运行结果： public class CatchWho { public static void main(String[] args) { try { try { throw new ArrayIndexOutOfBoundsException(); } catch (ArrayIndexOutOfBoundsException e) { System.

Using finally block vs writing code after the try/catch block

由 倖福魔咒の 提交于 2020-01-12 18:23:12
问题 As I understand, the following 2 examples should do the same thing. Why is the 1st considered better? 1: try { riskyMethod(); } catch(Exception e) { //handle exception } finally { cleanUp(); } 2: try { riskyMethod(); } catch(Exception e) { //handle exception } cleanUp(); EDIT: The example is in Java, but I'm wondering about the concept of a finally block in general, as used in any language 回答1: Well, for one thing if the "handle exception" part throws an exception itself, cleanup won't occur.

Using finally block vs writing code after the try/catch block

由 坚强是说给别人听的谎言 提交于 2020-01-12 18:22:08
问题 As I understand, the following 2 examples should do the same thing. Why is the 1st considered better? 1: try { riskyMethod(); } catch(Exception e) { //handle exception } finally { cleanUp(); } 2: try { riskyMethod(); } catch(Exception e) { //handle exception } cleanUp(); EDIT: The example is in Java, but I'm wondering about the concept of a finally block in general, as used in any language 回答1: Well, for one thing if the "handle exception" part throws an exception itself, cleanup won't occur.

try finally return问题

由 佐手、 提交于 2020-01-11 15:30:25
Try finally return问题 一、Finally不能被执行的情况： 1、 程序没有执行到try代码块 2、 Try 或者catch中调用exit()方法让虚拟机关闭 二、当try和finally中同时含有return语句时，程序是如何执行的，看下面代码： public class TryFinallyReturn { public static void main(String[] args) { // TODO Auto-generated method stub demo (); } static int demo() { try { System. out .println("执行try代码块"); return test1 (); } finally { System. out .println( " 执行 finally 代码块 " ); return test2 (); } } static int test1() { System. out .println("执行try中的return语句"); return 5; } static int test2() { System. out .println("执行finally代码块中的return语句"); return 2; } } 运行结果： 执行try代码块 执行try中的return语句

What is the point of finally in a try catch/except finally statement

由 半腔热情 提交于 2019-12-31 08:14:29
问题 I have used try-catch/except-finally variants in many languages for years, today someone asked me what is the point of finally and I couldn't answer. Basically why would you put a statement in finally instead of just putting it after the whole try-catch block? Or in other words is there a difference between the following blocks of code: try{ //a} catch {//b} finally {//c} try{//a} catch{//b} //c EDIT: PEOPLE, I know what finally does, I have been using it for ages, but my question is in the

In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil?

由 好久不见. 提交于 2019-12-29 02:17:08
问题 In Java, what purpose do the keywords final , finally and finalize fulfil? 回答1: final final can be used to mark a variable "unchangeable" private final String name = "foo"; //the reference name can never change final can also make a method not "overrideable" public final String toString() { return "NULL"; } final can also make a class not "inheritable". i.e. the class can not be subclassed. public final class finalClass {...} public class classNotAllowed extends finalClass {...} // Not

How to add a polyfill to support finally() in Edge?

由 余生长醉 提交于 2019-12-29 01:34:29
问题 I'm using axios library and using then(), catch() and finally(). Works perfectly in Chrome. However the finally() method does not work in MS Edge. I researched using polyfills or shims and I'm lost. I am not using webpack or transpiling and don't plan to add them. I need to keep this simple. How can I add a polyfill to make sure finally() works in Edge? Thanks! 回答1: This should handle the propagation of the thenable's species in addition to the behaviors detailed below: Promise.prototype

return eats exception

由 心已入冬 提交于 2019-12-27 17:37:18
问题 I found the following behavior at least weird : def errors(): try: ErrorErrorError finally: return 10 print errors() # prints: 10 # It should raise: NameError: name 'ErrorErrorError' is not defined The exception disappears when you use return inside a finally clause. Is that a bug? Is that documented anywhere? But the real question (and the answer I will mark as correct) is: What is the python developers' reason to allow that odd behavior? 回答1: You asked about the Python developers' reasoning
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