blocks|key|719932|text|您正在将字符串与==进行比较，这意味着您将检查这两个字符串是否确实是相同的字符串引用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|719933|使用equal()检查两个字符串是否包含相同的字符。|719934|请参阅：http://www.leepoint.net/notes-java/data/expressions/22compareobjects.html|719935|entityMap|0|LINK|mutability|MUTABLE|url|http://www.leepoint.net/notes-java/data/expressions/22compareobjects.html^0|8|2|0|2|7|0|4|21|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|X|8|@]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|J|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]]]

You're comparing strings with <code>==</code>, which means you're checking to see if these two strings are literally the same string reference.

Use <code>equal()</code> to check and see if two strings contain the same characters. 

See: <a href="http://www.leepoint.net/notes-java/data/expressions/22compareobjects.html" rel="nofollow">http://www.leepoint.net/notes-java/data/expressions/22compareobjects.html</a>

blocks|key|124182|text|对于字符串比较，您应该使用.equals，因此|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|124183|if(dataSource.substring(0,1)+==+"/")|code-block|syntax|javascript|124184|应该是|124185|if+("/".equals(dataSource.substring(0,1)))|124186|entityMap^0|D|7|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 should use <code>.equals</code> for string comparrisons
 so 

<pre><code>if(dataSource.substring(0,1) == "/")
</code></pre>

should be

<pre><code>if ("/".equals(dataSource.substring(0,1)))
</code></pre>

blocks|key|720096|text|对于字符串比较，使用equals方法，因为它比使用==运算符更可靠(它比较内容，而==比较引用)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720097|尝试使用equals方法：|720098|if(dataSource.substring(0,1).equals("/")){|code-block|syntax|javascript|720099|entityMap^0|A|6|P|2|15|2|0|4|6|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$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]]|$1|M|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|N|$]]

For string comparisons use <code>equals</code> method, as it is more reliable than using <code>==</code> operator (it compares the content while <code>==</code> comnpares the references ) :

Try using <code>equals</code> method :

<pre><code>if(dataSource.substring(0,1).equals("/")){
</code></pre>

blocks|key|4552011|text|使用.equals(Object)或.equalsIgnoreCase(String)比较字符串。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4552012|entityMap^0|2|F|I|P|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

Use <code>.equals(Object)</code> or <code>.equalsIgnoreCase(String)</code> for comparing Strings.

blocks|key|4552018|text|请使用.equals|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4552019|if("/".equals(dataSource.substring(0,1))){
++++System.out.println("trailing+forward+slash,+delete+it+");++
++++dataSource+=+dataSource.substring(1);
}|code-block|syntax|javascript|4552020|代替==|4552021|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

please use .equals

<pre><code>if("/".equals(dataSource.substring(0,1))){
 System.out.println("trailing forward slash, delete it "); 
 dataSource = dataSource.substring(1);
}
</code></pre>

instead of ==

blocks|key|720170|text|您需要执行dataSource.substring(0,1).equals("/")，它实际检查字符串的内容。==仅检查两端是否为同一对象。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720171|entityMap^0|5|11|1J|2|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

You need to do <code>dataSource.substring(0,1).equals("/")</code>, which actually checks the content of the strings. <code>==</code> only checks whether both sides are the same object.

blocks|key|4070215|text|尝尝这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4070216|if+((“要检查的字符串”).equals(MyString)){+doSomething()；}|4070217|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|$]]

Try this

if (("some string to check").equals(myString)){
 doSomething();
}

blocks|key|720214|text|如果你只想测试第一个字符，你可以尝试这个方法，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720215|dataSource.charAt(0)=='/'|offset|length|style|BOLD|720216|entityMap^0|0|0|P|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|$]]

If you want to test only, the first character , you can try the method,

dataSource.charAt(0)=='/'

blocks|key|4552135|text|在比较值时，请始终使用equals。话虽如此，您可以只使用indexOf方法来实现您的目的|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4552136|+++if+(dataSource.indexOf('/')+==+0)+{
++++++++dataSource+=+dataSource.substring(1);
++++}|code-block|syntax|javascript|4552137|entityMap^0|B|6|T|7|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

Always use <code>equals</code> when comparing values. Having said that you can just use <code>indexOf</code> method for your purpose 

<pre><code> if (dataSource.indexOf('/') == 0) {
 dataSource = dataSource.substring(1);
 }
</code></pre>

blocks|key|4070320|text|String+dataSource+=+"/hell";

++++++++if(dataSource.substring(0,1).equalsIgnoreCase("/")){
++++++++++++System.out.println("trailing+forward+slash,+delete+it+");++
++++++++++++dataSource+=+dataSource.substring(1);
++++++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4070321|运行这个程序。这起作用了..|unstyled|4070322|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>String dataSource = "/hell";

 if(dataSource.substring(0,1).equalsIgnoreCase("/")){
 System.out.println("trailing forward slash, delete it "); 
 dataSource = dataSource.substring(1);
 }
</code></pre>

run this program. this is working..

blocks|key|720340|text|为什么要使用字符串？你只是在为自己制造这个问题。使用提供的数据类型：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720341|InetAddress+dataSource+=+data.getInetAddress();|code-block|syntax|javascript|720342|或|720343|SocketAddress+dataSource+=+data.getRemoteSocketAddress();|720344|然后，在这两种情况下都有一个语义感知的.equals()方法。|offset|length|style|CODE|720345|entityMap^0|0|0|0|0|J|9|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@$M|X|N|Y|O|P]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Why use a String? You're just creating this problem for yourself. Use the datatype provided:

<pre><code>InetAddress dataSource = data.getInetAddress();
</code></pre>

or

<pre><code>SocketAddress dataSource = data.getRemoteSocketAddress();
</code></pre>

Then you have a semantically-aware <code>.equals()</code> method in both cases.

When I grab the IP Address from my open socket, as someone has sent me a stream, I noticed that the IP has a forward-slash.

I just plan to simply omit it. But first I want to validate the first character in the string is the forward-slash:

<pre><code>String dataSource = data.getAddress().toString();

if(dataSource.substring(0,1) == "/"){
 System.out.println("trailing forward slash, delete it "); 
 dataSource = dataSource.substring(1);
}
</code></pre>

This IF statement isn't being detected.

Anyone see what I'm doing wrong?

Java - If statement not working (comparing strings)

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。

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当我从我打开的套接字中获取IP地址时，因为有人向我发送了一个流，我注意到IP有一个正斜杠。我只打算简单地省略它。但首先，我想验证字符串中的第一个字符是正斜杠：String dataSource = data.getAddress().toString();if(dataSource.substring(0,1) == ...

问Java - If语句不工作(比较字符串)
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