blocks|key|676259|text|抛出异常是一种糟糕做法，因为这要求调用构造函数的任何人都要捕获异常，这是一种糟糕的做法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|676260|让一个构造函数(或任何方法)抛出一个异常是一个好主意，一般来说，IllegalArgumentException是未检查的，这样编译器就不会强迫你去捕捉它。|676261|如果你想让调用者捕捉到它，你应该抛出检查过的异常(从Exception扩展而来的东西，而不是RuntimeException)。|676262|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

It is bad practice to throw Exception, as that requires anyone who calls your constructor to catch Exception which is a bad practice.

It is a good idea to have a constructor (or any method) throw an exception, generally speaking IllegalArgumentException, which is unchecked, and thus the compiler doesn't force you to catch it.

You should throw checked exceptions (things that extend from Exception, but not RuntimeException) if you want the caller to catch it.

blocks|key|893030|text|我从来不认为在构造函数中抛出异常是一种糟糕的做法。在设计类时，您应该对该类的结构有一定的了解。如果其他人有不同的想法并试图执行该想法，那么您应该相应地出错，给用户关于错误是什么的反馈。在您的情况下，您可能会考虑如下内容|type|unstyled|depth|inlineStyleRanges|entityRanges|data|893031|if+(age+<+0)+throw+new+NegativeAgeException("The+person+you+attempted+"+%2B
+++++++++++++++++++++++"to+construct+must+be+given+a+positive+age.");|code-block|syntax|javascript|893032|其中，NegativeAgeException是您自己构造的异常类，可能会扩展另一个异常，如IndexOutOfBoundsException或类似的异常。|offset|length|style|CODE|893033|断言似乎也不太合适，因为您并不是在尝试发现代码中的bug。我想说，在这里使用异常终止绝对是正确的做法。|893034|entityMap^0|0|0|3|K|1A|P|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|P|$]]

I have never considered it to be a bad practice to throw an exception in the constructor. When the class is designed, you have a certain idea in mind of what the structure for that class should be. If someone else has a different idea and tries to execute that idea, then you should error accordingly, giving the user feedback on what the error is. In your case, you might consider something like

<pre><code>if (age &lt; 0) throw new NegativeAgeException("The person you attempted " +
 "to construct must be given a positive age.");
</code></pre>

where <code>NegativeAgeException</code> is an exception class that you constructed yourself, possibly extending another exception like <code>IndexOutOfBoundsException</code> or something similar.

Assertions don't exactly seem to be the way to go, either, since you're not trying to discover bugs in your code. I would say terminating with an exception is absolutely the right thing to do here.

blocks|key|676403|text|这是完全正确的，我一直都在这么做。如果它是参数检查的结果，我通常使用IllegalArguemntException。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|676404|在这种情况下，我不建议使用断言，因为它们在部署构建中被关闭，您总是希望阻止这种情况发生，但如果您的团队在启用断言的情况下执行所有测试，并且您认为在运行时丢失参数问题的可能性比抛出可能更有可能导致运行时崩溃的异常更容易接受，则断言是有效的。|676405|而且，assert对于调用者来说更难捕获，这很容易。|676406|您可能希望在方法的javadoc中将其列为“抛出”，并说明原因，这样调用者就不会感到惊讶。|676407|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

This is totally valid, I do it all the time. I usually use IllegalArguemntException if it is a result of parameter checking.

In this case I wouldn't suggest asserts because they are turned off in a deployment build and you always want to stop this from happening, but they are valid if your group does ALL it's testing with asserts turned on and you think the chance of missing a parameter problem at runtime is more acceptable than throwing an exception that is maybe more likely to cause a runtime crash. 

Also, an assert would be more difficult for the caller to trap, this is easy.

You probably want to list it as a "throws" in your method's javadocs along with the reason so that callers aren't surprised.

blocks|key|893124|text|您不需要引发检查过的异常。这是程序控制范围内的一个bug，因此您希望抛出一个未检查的异常。使用Java语言已经提供的未检查异常之一，比如IllegalArgumentException、IllegalStateException或NullPointerException。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|893125|您可能还想摆脱setter。您已经提供了一种通过构造函数启动age的方法。实例化后是否需要更新？如果不是，则跳过setter。一条好的规则是，不要把事情公之于众。从私有或默认开始，使用final保护您的数据。现在每个人都知道Person已经被正确构造，并且是不可变的。它可以自信地使用。|893126|这很可能是你真正需要的：|893127|class+Person+{+

++private+final+int+age;+++

++Person(int+age)+{++++

++++if+(age+<+0)+
+++++++throw+new+IllegalArgumentException("age+less+than+zero:+"+%2B+age);+

++++this.age+=+age;+++
++}

++//+setter+removed|code-block|syntax|javascript|893128|entityMap^0|1W|O|2L|L|37|K|0|U|3|2K|5|34|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|14|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|15|8|@]|D|@]|E|$M|N]]|$1|O|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|P|$]]

You do not need to throw a checked exception. This is a bug within the control of the program, so you want to throw an unchecked exception. Use one of the unchecked exceptions already provided by the Java language, such as <code>IllegalArgumentException</code>, <code>IllegalStateException</code> or <code>NullPointerException</code>. 

You may also want to get rid of the setter. You've already provided a way to initiate <code>age</code> through the constructor. Does it need to be updated once instantiated? If not, skip the setter. A good rule, do not make things more public than necessary. Start with private or default, and secure your data with <code>final</code>. Now everyone knows that <code>Person</code> has been constructed properly, and is immutable. It can be used with confidence.

Most likely this is what you really need:

<pre><code>class Person { 

 private final int age; 

 Person(int age) { 

 if (age &lt; 0) 
 throw new IllegalArgumentException("age less than zero: " + age); 

 this.age = age; 
 }

 // setter removed
</code></pre>

Is it a good practice to make the constructor throw an exception?
For example I have a class <code>Person</code> and I have <code>age</code> as its only attribute. Now
I provide the class as

<pre><code>class Person{
 int age;
 Person(int age) throws Exception{
 if (age&lt;0)
 throw new Exception("invalid age");
 this.age = age;
 }

 public void setAge(int age) throws Exception{
 if (age&lt;0)
 throw new Exception("invalid age");
 this.age = age;
 }
}
</code></pre>

Is it good practice to make the constructor throw an exception?

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让构造函数抛出异常是一种好的做法吗？例如，我有一个Person类，并且age是它唯一的属性。现在我将这个类提供为class Person{ int age; Person(int age) throws Exception{ if (age<0) throw new Exception("inval...

问让构造函数抛出异常是一种好的做法吗？
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