blocks|key|199361|text|您可以使用一些值符来实现此目的。就像芭乐图书馆里的选修课一样。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|199362|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|$]]

You can use some value holder for this purpose. Like Optional class in guava library.

blocks|key|199382|text|我会更好地更改setter方法，这样，如果值为null或empty，则将N/A分配给该属性。因此，如果在类内的其他方法中使用该属性(v.g.toString())，您将在那里获得预期的值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|199383|或者，将setter方法更改为在所设置的值不正确时启动异常，以便程序员在设置该值之前必须改进其处理。|199384|除此之外，这是可以的。|199385|entityMap^0|N|4|10|3|1Y|A|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|T|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|K|$]]

I would change better the setter method so, if the value is <code>null</code> or empty, the <code>N/A</code> is assigned to the attribute. So, if you use the attribute in other methods inside the class (v.g. <code>toString()</code>) you will have the intended value there.

Alternatively, change the setter method to launch an exception when the value being set is not right, so the programmer is forced to improve its handling prior to setting the value.

Other than that, it is ok.

blocks|key|199405|text|我认为初始化this.myValue+=+"N/A"会更好。后续对setMyValue的调用应根据您的业务情况修改this.myValue。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|199406|getMyValue不应该以任何方式修改this.myValue。如果您需要返回某个值，则应该返回该值(如"N/A")，而不是更改this.myValue。Getters不能修改成员的值。|199407|entityMap^0|6|K|X|A|1L|C|0|0|A|K|C|1T|C|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|I|$]]

I think it's better to initialize <code>this.myValue = "N/A"</code>. And subsequent calls to <code>setMyValue</code> should modify the <code>this.myValue</code> according to your business conditions. 
The <code>getMyValue</code> shouldn't modify in any way <code>this.myValue</code>. If your needs are to return a certain value, you should return that value (like "N/A") and not alter <code>this.myValue</code> . Getters must not modify member's value.

blocks|key|417600|text|在我看来，除非您正在执行lazy-loading+(在这种情况下您并不是这样)，否则getters不应该更改该值。所以我要么：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|417601|将更改放入setter中|417602|public+void+setMyValue(String+value)+{
++++if(value+==+null+%7C%7C+value.isEmpty()){
++++++++this.myValue+=+"N/A";
++++}+else+{
++++++++this.myValue+=+value;
++++}
}|code-block|syntax|javascript|417603|或者，如果value设置不正确，则让getter返回默认值：|417604|public+String+getMyValue()+{
++++if(this.myvalue+==+null+%7C%7C+this.myvalue.isEmpty()){
++++++++return+"N/A";
++++}++++
++++return+this.myValue;
}|417605|在延迟加载的情况下，我会说在getter中更改成员是可以的，您可以这样做：|417606|public+String+getMyValue()+{
++++if+(this.myvalue+==+null)+{
++++++++this.myvalue+=+loadMyValue();
++++}++++
++++return+this.myValue;
}|417607|entityMap^0|C|C|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|11|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|13|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|U|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|V|$]]

In my opinion, unless you are doing <code>lazy-loading</code> (which you are not in that case), getters should not change the value. So I would either:

Put the change in the setter

<pre><code>public void setMyValue(String value) {
 if(value == null || value.isEmpty()){
 this.myValue = "N/A";
 } else {
 this.myValue = value;
 }
}
</code></pre>

Or make the getter return a default value if value not set properly:

<pre><code>public String getMyValue() {
 if(this.myvalue == null || this.myvalue.isEmpty()){
 return "N/A";
 } 
 return this.myValue;
}
</code></pre>

In the case of lazy-loading, where I would say that changing your members in a getter is fine, you would do something like:

<pre><code>public String getMyValue() {
 if (this.myvalue == null) {
 this.myvalue = loadMyValue();
 } 
 return this.myValue;
}
</code></pre>

blocks|key|417625|text|你喜欢做什么就做什么。毕竟，getter和setter只是另一种公共方法。您可以使用任何其他名称。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|417626|但是如果你使用像Spring这样的框架，你一定会使用那些标准的名字，并且你永远不应该把你的自定义代码放在里面。|offset|length|style|CODE|417627|entityMap^0|0|8|6|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Do what ever you like. After all getters and setters are just another public methods. You could use any other names.

But if you use frameworks like <code>Spring</code>, you are bound to use those standard names and you should never put your custom codes inside them.

blocks|key|199481|text|不是的。您在这里做了两件事。获取和设置。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|199482|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|$]]

No. You're doing two things here. Getting and setting.

blocks|key|199548|text|这实际上在很大程度上取决于您想要使用get()-method强制执行的约定。根据契约式设计约定，调用者必须确保满足前提条件(这意味着在setter方法中进行验证通常是糟糕的设计)，而被调用者(我不知道这是不是正确的英文术语，即被调用的术语)则确保满足post条件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|199549|如果您定义的约定是不允许get()-method更改对象的，那么您就违反了自己的约定。考虑实现像这样的方法|199550|public+isValid()+{
++++return+(this.myvalue+==+null+%7C%7C+this.myvalue.isEmpty());
}|code-block|syntax|javascript|199551|这种方法的优点是，您不必检查get()的返回值是"N/A“还是其他值。这也可以在调用set()之前调用，以验证您没有将非法值插入到对象中。|199552|如果你想设置一个默认值，你应该在初始化时设置。|199553|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This actually highly depends on the contract you want to enforce with your get()-method. According to design-by-contract conventions the caller has to make sure that the preconditions are met (which means doing a validation in a setter method often is actually bad design) and the callee (I do not know if that's the correct english term for that, i.e., the called one) makes sure that the post conditions are met. 

If you define your contract so that the get()-method is not allowed to change the object then you are breaking your own contract. Think about implementing a method like 

<pre><code>public isValid() {
 return (this.myvalue == null || this.myvalue.isEmpty());
}
</code></pre>

Advantage of this approach is that you do not have to check wether the return of your get() is "N/A" or something else. This also can be called before calling set() to validate that you do not insert illegal values into your object. 

If you want to set a default value you should do that during initialization.

blocks|key|417755|text|我通常定义一个特定的getter。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|417756|切勿更改原始getter|417757|+public+String+getMyValue(){
+++++return+this.myValue
+}|code-block|syntax|javascript|417758|并创建特定的getter|417759|public+String+getMyValueFormatted(){

++++if(this.myvalue+==+null+%7C%7C+this.myvalue.isEmpty()){
+++++++return+"N/A";
++++}else{
+++++++return+this.myValue;
++++}
+}|417760|entityMap^0|A|6|0|6|6|0|0|6|6|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

I usually define a specific <code>getter</code>.

Never alter original <code>getter</code>:

<pre><code> public String getMyValue(){
 return this.myValue
 }
</code></pre>

And create a specific <code>getter</code>:

<pre><code>public String getMyValueFormatted(){

 if(this.myvalue == null || this.myvalue.isEmpty()){
 return "N/A";
 }else{
 return this.myValue;
 }
 }
</code></pre>

blocks|key|199620|text|绝对是的，这是一个糟糕的练习。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|199621|假设您通过网络与第三方(远程处理、COM等)通信，这将增加往返时间，进而影响应用程序性能。|199622|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

absolutely yes, it's a bad pratice.

Imagine you communicate accross network with a third party (remoting, COM, ...), this will increase the round-trip and then hit application performance.

blocks|key|417875|text|getters中的状态更改应该是一种吊死的冒犯。这意味着客户端代码必须注意访问getter和setter的顺序，而且要做到这一点，它必须了解实现。您应该能够以任何顺序调用getter，并且仍然可以获得相同的结果。当setter根据对象的当前状态修改传入的值时，就会出现相关的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|417876|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|$]]

State changes in getters should be a hanging offence. It means that client code must be careful about the order in which it accesses getters and setters and to do this it must have knowledge of the implementation. You should be able to call the getters in any order and still get the same results. A related problem occurs when the setter modifies the incoming value depending on the current state of the object.

Is it bad practice to change my getter method like version 2 in my class.

Version 1:

<pre><code> public String getMyValue(){
 return this.myValue
 }
</code></pre>

Version 2:

<pre><code> public String getMyValue(){

 if(this.myValue == null || this.myValue.isEmpty()){
 this.myValue = "N/A";
 }

 return this.myValue;
 }
</code></pre>

Is it bad practice to have my getter method change the stored value?

往返时间

在我的类中更改像版本2这样的getter方法是不是不好的做法？版本1： public String getMyValue(){     return this.myValue }版本2： public String getMyValue(){    if(this.myValue == null || this.myV...

问让我的getter方法更改存储值是不是一种糟糕的做法？
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问让我的getter方法更改存储值是不是一种糟糕的做法？
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