blocks|key|1925088|text|是。FileNotFoundException是从IOException继承的。必须首先捕获异常的子类。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1925089|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Yes. The FileNotFoundException is inherited from the IOException. Exception's subclasses have to be caught first.

blocks|key|1925140|text|是的，应该先写具体的异常，然后再写更广泛的异常，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1925141|这就像你先给房间里的所有动物打电话，然后再试着看看外面有没有人|1925142|例如的|1925143|try{
++//do+something
}catch(Exception+ex){

}catch(NullPointerException+npe){

}|code-block|syntax|javascript|1925144|会给你带来编译时错误|offset|length|style|BOLD|1925145|entityMap^0|0|0|0|0|0|A|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|U|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|W|8|@$M|X|N|Y|O|P]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Yes, Specific exception should be written first, broader after that, 

Its like you call all the animals first in the room and after you try to see if there is any human outside 

For example

<pre><code>try{
 //do something
}catch(Exception ex){

}catch(NullPointerException npe){

}
</code></pre>

Will give you compile time error

blocks|key|1925375|text|必须在捕获一般异常之前捕获特定异常，否则将出现无法访问的代码错误。例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1925376|try{
++//do+something
}catch(NullPointerException+npe){

}catch(NumberFormatException+nfe){

}catch(Exception+exp){

}|code-block|syntax|javascript|1925377|如果将Exception+catch块放在NullPointerException或NumberFormatException+catch块之前，将会出现编译时错误。(无法访问的代码)。|offset|length|style|CODE|1925378|entityMap^0|0|0|3|9|L|K|16|L|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

Specific Exceptions must be caught prior to general exception or else you will get an unreachable code error.
For example -

<pre><code>try{
 //do something
}catch(NullPointerException npe){

}catch(NumberFormatException nfe){

}catch(Exception exp){

}
</code></pre>

If you put the <code>Exception</code> catch block before the <code>NullPointerException</code> or <code>NumberFormatException</code> catch block, you will get a compile time error. (Unreachable code).

blocks|key|3650483|text|换句话说，我建议您三思而后行，首先是否需要所有这些catch块。您确定要为每个案例提供不同的有意义的处理吗？如果您只是要打印出一条消息，那么您只能捕获IOException来执行此操作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3650484|entityMap^0|23|B|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

On a tangent, I would advise you to think twice whether you need all those catch blocks in the first place. Are you sure you are going to provide meaningful handling for each case differently? If you are just going to print out a message, you can only catch <code>IOException</code> to do that.

blocks|key|3562473|text|从子类到超类的well...start+...这是理想的代码，您将得到unreachable代码错误|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3562474|entityMap^0|Z|F|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

well...start from subclasses to superclass...that's the ideal way..otherwise you will get unreachable code error

blocks|key|1925248|text|当然可以。更具体的异常应该写在第一个catch块中，而像catch(Exception+ex){ex.printStackTrace();}这样的通用异常应该写在最后一组catch块中。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1925249|如果您尝试另一种方式，那么编译器将无法访问您的特定异常！|BOLD|1925250|entityMap^0|S|16|0|D|F|0^^$0|@$1|2|3|4|5|6|7|K|8|@$9|L|A|M|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|N|8|@$9|O|A|P|B|H]]|D|@]|E|$]]|$1|I|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|J|$]]

Yes Of Course. The more specific exception should be written in the first catch block and the generic exceptions like <code>catch(Exception ex){ex.printStackTrace();}</code> should be written in the final set of catch block.

If you try the other way then, your specific exception will be unreachable by the JVM compiler!

blocks|key|1925291|text|IOException是FileNotFoundException的超类。因此，如果您将用于IOException的+catch+语句放在用于FileNotFoundException的语句之上，那么第二个catch的代码将变得不可用，编译器将为此抛出一个error。原因很简单：every+object+of+a+sub+class+can+be+easily+accepted+by+a+super+class+reference。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|1925292|entityMap^0|0|B|C|L|1A|B|1Z|L|3K|5|3W|25|1M|7|0^^$0|@$1|2|3|4|5|6|7|I|8|@$9|J|A|K|B|C]|$9|L|A|M|B|C]|$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|D]]|E|@]|F|$]]|$1|G|3|-4|5|6|7|X|8|@]|E|@]|F|$]]]|H|$]]

<code>IOException</code> is the super class of <code>FileNotFoundException</code>. So, if you put the catch statement for <code>IOException</code> above that for <code>FileNotFoundException</code>, then the code for second catch will become unreachable and the compiler will throw an <code>error</code> for that. Reason is simple: <code>every object of a sub class can be easily accepted by a super class reference</code>.

blocks|key|3562708|text|IOException是FileNotFoundException+.So+fist+catch子类的超类，即FileNotFoundException，然后您需要捕获IOException|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3562709|例如,|3562710|try{
++++++//+something
+++}+catch(FileNotFoundException+fne){
++++++//+Handle+the+exception+here
+++}+catch(IOException+ioe)+{
++++++//+Handle+the+IOException+here
+++}|code-block|syntax|javascript|3562711|entityMap^0|0|2N|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

IOException is the super class of FileNotFoundException .So fist catch sub class i.e FileNotFoundException and then you need to catch IOException

For Example,

<pre><code>try{
 // something
 } catch(FileNotFoundException fne){
 // Handle the exception here
 } catch(IOException ioe) {
 // Handle the IOException here
 }
</code></pre>

In <code>try</code>-<code>catch</code> syntax, does it matter in what order catch statements for <code>FileNotFoundException</code> and <code>IOExceptipon</code> are written?

Order of catch statement?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

在try-catch语法中，FileNotFoundException和IOExceptipon的catch语句的编写顺序重要吗？

问catch语句的顺序？
EN

回答 8

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问catch语句的顺序？EN

回答 8

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问catch语句的顺序？
EN