blocks|key|461635|text|使用三元运算符：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|461636|name+=+((city.getName()+==+null)+?+"N/A"+:+city.getName());|code-block|syntax|javascript|461637|我认为你有倒退的条件-如果它是null，你想要的值是"N/A“。|461638|如果city为空怎么办？在这种情况下，你的代码就完蛋了。我会添加另一项检查：|461639|name+=+((city+==+null)+%7C%7C+(city.getName()+==+null)+?+"N/A"+:+city.getName());|461640|entityMap^0|0|0|0|0|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]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Use the ternary operator:

<pre><code>name = ((city.getName() == null) ? "N/A" : city.getName());
</code></pre>

I think you have the conditions backwards - if it's null, you want the value to be "N/A".

What if city is null? Your code *hits the bed in that case. I'd add another check:

<pre><code>name = ((city == null) || (city.getName() == null) ? "N/A" : city.getName());
</code></pre>

blocks|key|461748|text|为了避免两次调用.getName()，我将使用|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|461749|name+=+city.getName();
if+(name+==+null)+name+=+"N/A";|code-block|syntax|javascript|461750|entityMap^0|8|A|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

To avoid calling <code>.getName()</code> twice I would use

<pre><code>name = city.getName();
if (name == null) name = "N/A";
</code></pre>

blocks|key|461715|text|方法是使用三元运算符：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|461716|name+=+city.getName()+==+null+?+city.getName()+:+"N/A"|code-block|syntax|javascript|461717|然而，我相信你在上面的代码中有一个拼写错误，你的意思是说：|461718|if+(city.getName()+!=+null)+...|461719|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The way to do it is with ternary operator:

<pre><code>name = city.getName() == null ? city.getName() : "N/A"
</code></pre>

However, I believe you have a typo in your code above, and you mean to say:

<pre><code>if (city.getName() != null) ...
</code></pre>

blocks|key|676955|text|在java+8中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|676956|name+=+Optional.ofNullable(city.getName()).orElse("N/A")|code-block|syntax|javascript|676957|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

in java 8:

<pre><code>name = Optional.ofNullable(city.getName()).orElse("N/A")
</code></pre>

blocks|key|461780|text|您可以以简短的形式编写if,+else+if,+else语句。例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|461781|Boolean+isCapital+=+city.isCapital();+//Object+Boolean+(not+boolean)
String+isCapitalName+=+isCapital+==+null+?+""+:+isCapital+?+"Capital"+:+"City";++++++|code-block|syntax|javascript|461782|这是以下格式的缩写：|461783|Boolean+isCapital+=+city.isCapital();
String+isCapitalName;
if(isCapital+==+null)+{
++++isCapitalName+=+"";
}+else+if(isCapital)+{
++++isCapitalName+=+"Capital";
}+else+{
++++isCapitalName+=+"City";
}|461784|entityMap^0|B|H|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

You can write <code>if, else if, else</code> statements in short form. For example:

<pre><code>Boolean isCapital = city.isCapital(); //Object Boolean (not boolean)
String isCapitalName = isCapital == null ? "" : isCapital ? "Capital" : "City"; 
</code></pre>

This is short form of:

<pre><code>Boolean isCapital = city.isCapital();
String isCapitalName;
if(isCapital == null) {
 isCapitalName = "";
} else if(isCapital) {
 isCapitalName = "Capital";
} else {
 isCapitalName = "City";
}
</code></pre>

blocks|key|461466|text|name+=+(city.getName()+!=+null)+?+city.getName()+:+"N/A";|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|461467|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>name = (city.getName() != null) ? city.getName() : "N/A";
</code></pre>

blocks|key|461929|text|下面是一行代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|461930|name+=+(city.getName()+!=+null)+?+city.getName()+:+"N/A";|code-block|syntax|javascript|461931|下面是它工作原理示例，在js文件中运行下面的代码，并理解结果。此("Data"+!=+null)是条件，就像我们在普通if()中所做的那样，当此条件为真时，"Data"是语句。此"+:+"充当else，而"N/A"是else条件的语句。希望这能帮助你理解其中的逻辑。|offset|length|style|CODE|461932|​|461933|name+=+("Data"+!=+null)+?+"Data"+:+"N/A";

console.log(name);|461934|461935|entityMap^0|0|0|W|G|1N|4|26|6|2H|5|2U|5|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|U|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|V|8|@$I|W|J|X|K|L]|$I|Y|J|Z|K|L]|$I|10|J|11|K|L]|$I|12|J|13|K|L]|$I|14|J|15|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|16|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|Q|3|N|5|6|7|18|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|S|$]]

here is one line code 

<pre><code>name = (city.getName() != null) ? city.getName() : "N/A";
</code></pre>

here is example how it work, run below code in js file and understand the result. This <code>("Data" != null)</code> is condition as we do in normal <code>if()</code> and <code>"Data"</code> is statement when this condition became true. this <code>" : "</code> act as else and <code>"N/A"</code> is statement for else condition. Hope this help you to understand the logic. 

<div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>name = ("Data" != null) ? "Data" : "N/A";

console.log(name);</code></pre>
</div>
</div>

blocks|key|461868|text|使用org.apache.commons.lang3.StringUtils：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|461869|name+=+StringUtils.defaultString(city.getName(),+"N/A");|code-block|syntax|javascript|461870|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Use org.apache.commons.lang3.StringUtils:

<pre><code>name = StringUtils.defaultString(city.getName(), "N/A");
</code></pre>

blocks|key|677065|text|你可以用这种方式让它变得更容易：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|677066|name+=+city.getName()+==+null+?+city.getName()+:+"N/A"|code-block|syntax|javascript|677067|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could make it much easier this way :
<pre><code>name = city.getName() == null ? city.getName() : &quot;N/A&quot;
</code></pre>

blocks|key|676817|text|name+=+city.getName()!=null?city.getName():"N/A"|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|676818|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>name = city.getName()!=null?city.getName():"N/A"
</code></pre>

I know there is a way for writing a Java <code>if</code> statement in short form.

<pre><code>if (city.getName() != null) {
 name = city.getName();
} else {
 name="N/A";
}
</code></pre>

Does anyone know how to write the short form for the above 5 lines into one line?

Short form for Java if statement

我知道有一种方法可以用简短的形式编写Java if语句。if (city.getName() != null) {    name = city.getName();} else {    name="N/A";}有人知道如何将上述5行的缩写写成一行吗？

问Java if语句的缩写形式
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