blocks|key|1326347|text|这是一种我们不应该自己做的代码。把库用在平凡的东西上，把你的大脑留给难的东西。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326348|在这种情况下，我建议使用Apache+Commons+IO中的FilenameUtils.removeExtension()|offset|length|1326349|entityMap|0|LINK|mutability|MUTABLE|url|http://commons.apache.org/io/|1|http://commons.apache.org/proper/commons-io/javadocs/api-2.5/org/apache/commons/io/FilenameUtils.html#removeExtension%2528java.lang.String%2529^0|0|C|H|0|V|V|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]|$D|U|E|V|1|W]]|A|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]|N|$5|I|J|K|A|$L|O]]]]

This is the sort of code that we shouldn't be doing ourselves. Use libraries for the mundane stuff, save your brain for the hard stuff.

In this case, I recommend using <a href="http://commons.apache.org/proper/commons-io/javadocs/api-2.5/org/apache/commons/io/FilenameUtils.html#removeExtension%28java.lang.String%29" rel="noreferrer">FilenameUtils.removeExtension()</a> from <a href="http://commons.apache.org/io/" rel="noreferrer">Apache Commons IO</a>

blocks|key|1326184|text|str.substring(0,+str.lastIndexOf('.'))|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326185|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>str.substring(0, str.lastIndexOf('.'))
</code></pre>

blocks|key|1541474|text|顺便说一句，在我的例子中，当我想要一个快速的解决方案来删除一个特定的扩展时，这大概是我所做的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541475|++if+(filename.endsWith(ext))
++++return+filename.substring(0,filename.length()+-+ext.length());
++else
++++return+filename;|code-block|syntax|javascript|1541476|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|$]]

BTW, in my case, when I wanted a quick solution to remove a specific extension, this is approximately what I did:

<pre><code> if (filename.endsWith(ext))
 return filename.substring(0,filename.length() - ext.length());
 else
 return filename;
</code></pre>

blocks|key|1326201|text|String+foo+=+"title+part1.txt";
foo+=+foo.substring(0,+foo.lastIndexOf('.'));|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326202|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>String foo = "title part1.txt";
foo = foo.substring(0, foo.lastIndexOf('.'));
</code></pre>

blocks|key|1541369|text|String+fileName="foo.bar";
int+dotIndex=fileName.lastIndexOf('.');
if(dotIndex>=0)+{+//+to+prevent+exception+if+there+is+no+dot
++fileName=fileName.substring(0,dotIndex);
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1541370|这是刁钻的问题吗？:p|unstyled|1541371|我想不出更快的方法来取款机。|1541372|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>String fileName="foo.bar";
int dotIndex=fileName.lastIndexOf('.');
if(dotIndex&gt;=0) { // to prevent exception if there is no dot
 fileName=fileName.substring(0,dotIndex);
}
</code></pre>

Is this a trick question? :p

I can't think of a faster way atm.

blocks|key|1541941|text|你可以尝试这个功能，非常基础|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541942|public+String+getWithoutExtension(String+fileFullPath){
++++return+fileFullPath.substring(0,+fileFullPath.lastIndexOf('.'));
}|code-block|syntax|javascript|1541943|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 can try this function , very basic 

<pre><code>public String getWithoutExtension(String fileFullPath){
 return fileFullPath.substring(0, fileFullPath.lastIndexOf('.'));
}
</code></pre>

blocks|key|1326769|text|如果你的项目已经依赖于谷歌核心库，可以使用com.google.common.io.Files类中的方法。您需要的方法是getNameWithoutExtension。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1326770|entityMap^0|L|Q|1O|N|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 a method in <code>com.google.common.io.Files</code> class if your project is already dependent on Google core library. The method you need is <code>getNameWithoutExtension</code>.

blocks|key|1326397|text|filename.substring(filename.lastIndexOf('.'),+filename.length()).toLowerCase();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326398|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>filename.substring(filename.lastIndexOf('.'), filename.length()).toLowerCase();
</code></pre>

blocks|key|1541801|text|使用正则表达式。这一点替换了最后一个点，以及它之后的所有内容。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541802|String+baseName+=+fileName.replaceAll("\\.[%5E.]*$",+"");|code-block|syntax|javascript|1541803|如果想要预编译正则表达式，还可以创建一个模式对象。|1541804|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|$]]

Use a regex. This one replaces the last dot, and everything after it.

<pre><code>String baseName = fileName.replaceAll("\\.[^.]*$", "");
</code></pre>

You can also create a Pattern object if you want to precompile the regex.

blocks|key|1541640|text|String[]+splitted+=+fileName.split(".");
String+fileNameWithoutExtension+=+fileName.replace("."+%2B+splitted[splitted.length+-+1],+"");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1541641|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>String[] splitted = fileName.split(".");
String fileNameWithoutExtension = fileName.replace("." + splitted[splitted.length - 1], "");
</code></pre>

blocks|key|1326575|text|使用字符串图像路径创建新文件|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326576|String+imagePath;
File+test+=+new+File(imagePath);
test.getName();
test.getPath();
getExtension(test.getName());


public+static+String+getExtension(String+uri)+{
++++++++if+(uri+==+null)+{
++++++++++++return+null;
++++++++}

++++++++int+dot+=+uri.lastIndexOf(".");
++++++++if+(dot+>=+0)+{
++++++++++++return+uri.substring(dot);
++++++++}+else+{
++++++++++++//+No+extension.
++++++++++++return+"";
++++++++}
++++}|code-block|syntax|javascript|1326577|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|$]]

create a new file with string image path

<pre><code>String imagePath;
File test = new File(imagePath);
test.getName();
test.getPath();
getExtension(test.getName());


public static String getExtension(String uri) {
 if (uri == null) {
 return null;
 }

 int dot = uri.lastIndexOf(".");
 if (dot &gt;= 0) {
 return uri.substring(dot);
 } else {
 // No extension.
 return "";
 }
 }
</code></pre>

blocks|key|1541719|text|org.apache.commons.io.FilenameUtils版本2.4给出了以下答案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541720|public+static+String+removeExtension(String+filename)+{
++++if+(filename+==+null)+{
++++++++return+null;
++++}
++++int+index+=+indexOfExtension(filename);
++++if+(index+==+-1)+{
++++++++return+filename;
++++}+else+{
++++++++return+filename.substring(0,+index);
++++}
}

public+static+int+indexOfExtension(String+filename)+{
++++if+(filename+==+null)+{
++++++++return+-1;
++++}
++++int+extensionPos+=+filename.lastIndexOf(EXTENSION_SEPARATOR);
++++int+lastSeparator+=+indexOfLastSeparator(filename);
++++return+lastSeparator+>+extensionPos+?+-1+:+extensionPos;
}

public+static+int+indexOfLastSeparator(String+filename)+{
++++if+(filename+==+null)+{
++++++++return+-1;
++++}
++++int+lastUnixPos+=+filename.lastIndexOf(UNIX_SEPARATOR);
++++int+lastWindowsPos+=+filename.lastIndexOf(WINDOWS_SEPARATOR);
++++return+Math.max(lastUnixPos,+lastWindowsPos);
}

public+static+final+char+EXTENSION_SEPARATOR+=+'.';
private+static+final+char+UNIX_SEPARATOR+=+'/';
private+static+final+char+WINDOWS_SEPARATOR+=+'\\';|code-block|syntax|javascript|1541721|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|$]]

org.apache.commons.io.FilenameUtils version 2.4 gives the following answer

<pre><code>public static String removeExtension(String filename) {
 if (filename == null) {
 return null;
 }
 int index = indexOfExtension(filename);
 if (index == -1) {
 return filename;
 } else {
 return filename.substring(0, index);
 }
}

public static int indexOfExtension(String filename) {
 if (filename == null) {
 return -1;
 }
 int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);
 int lastSeparator = indexOfLastSeparator(filename);
 return lastSeparator &gt; extensionPos ? -1 : extensionPos;
}

public static int indexOfLastSeparator(String filename) {
 if (filename == null) {
 return -1;
 }
 int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
 int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
 return Math.max(lastUnixPos, lastWindowsPos);
}

public static final char EXTENSION_SEPARATOR = '.';
private static final char UNIX_SEPARATOR = '/';
private static final char WINDOWS_SEPARATOR = '\\';
</code></pre>

blocks|key|1326615|text|+private+String+trimFileExtension(String+fileName)
++{
+++++String[]+splits+=+fileName.split(+"\\."+);
+++++return+StringUtils.remove(+fileName,+"."+%2B+splits[splits.length+-+1]+);
++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326616|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> private String trimFileExtension(String fileName)
 {
 String[] splits = fileName.split( "\\." );
 return StringUtils.remove( fileName, "." + splits[splits.length - 1] );
 }
</code></pre>

blocks|key|1326225|text|我会这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326226|String+title_part+=+"title+part1.txt";
int+i;
for(i=title_part.length()-1+;+i>=0+&&+title_part.charAt(i)!='.'+;+i--);
title_part+=+title_part.substring(0,i);|code-block|syntax|javascript|1326227|从头到尾一直到“.”然后调用substring。|1326228|编辑:可能不是高尔夫球，但它很有效:)|1326229|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]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I would do like this:

<pre><code>String title_part = "title part1.txt";
int i;
for(i=title_part.length()-1 ; i&gt;=0 &amp;&amp; title_part.charAt(i)!='.' ; i--);
title_part = title_part.substring(0,i);
</code></pre>

Starting to the end till the '.' then call substring.

Edit:
Might not be a golf but it's effective :)

blocks|key|1541862|text|请记住没有文件扩展名或有多个文件扩展名的情况|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541863|示例文件名:+file+%7C+file.txt+%7C+file.tar.bz2|1541864|/**
+*
+*+@param+fileName
+*+@return+file+extension
+*+example+file.fastq.gz+=>+fastq.gz
+*/
private+String+extractFileExtension(String+fileName)+{
++++String+type+=+"undefined";
++++if+(FilenameUtils.indexOfExtension(fileName)+!=+-1)+{
++++++++String+fileBaseName+=+FilenameUtils.getBaseName(fileName);
++++++++int+indexOfExtension+=+-1;
++++++++while+(fileBaseName.contains("."))+{
++++++++++++indexOfExtension+=+FilenameUtils.indexOfExtension(fileBaseName);
++++++++++++fileBaseName+=+FilenameUtils.getBaseName(fileBaseName);
++++++++}
++++++++type+=+fileName.substring(indexOfExtension+%2B+1,+fileName.length());
++++}
++++return+type;
}|code-block|syntax|javascript|1541865|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Keeping in mind the scenarios where there is no file extension or there is more than one file extension

example Filename : file | file.txt | file.tar.bz2

<pre><code>/**
 *
 * @param fileName
 * @return file extension
 * example file.fastq.gz =&gt; fastq.gz
 */
private String extractFileExtension(String fileName) {
 String type = "undefined";
 if (FilenameUtils.indexOfExtension(fileName) != -1) {
 String fileBaseName = FilenameUtils.getBaseName(fileName);
 int indexOfExtension = -1;
 while (fileBaseName.contains(".")) {
 indexOfExtension = FilenameUtils.indexOfExtension(fileBaseName);
 fileBaseName = FilenameUtils.getBaseName(fileBaseName);
 }
 type = fileName.substring(indexOfExtension + 1, fileName.length());
 }
 return type;
}
</code></pre>

blocks|key|1541958|text|public+static+String+removeExtension(String+file)+{
++++if(file+!=+null+&&+file.length()+>+0)+{
++++++++while(file.contains("."))+{
++++++++++++file+=+file.substring(0,+file.lastIndexOf('.'));
++++++++}
++++}
++++return+file;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1541959|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>public static String removeExtension(String file) {
 if(file != null &amp;&amp; file.length() &gt; 0) {
 while(file.contains(".")) {
 file = file.substring(0, file.lastIndexOf('.'));
 }
 }
 return file;
}
</code></pre>

blocks|key|1541986|text|为了坚持Path类，我能写出的最好的东西是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1541987|Path+removeExtension(Path+path)+{
++++return+path.resolveSibling(path.getFileName().toString().replaceFirst("\\.[%5E.]*$",+""));
}|code-block|syntax|javascript|1541988|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|$]]

The best what I can write trying to stick to the Path class:
<pre><code>Path removeExtension(Path path) {
 return path.resolveSibling(path.getFileName().toString().replaceFirst(&quot;\\.[^.]*$&quot;, &quot;&quot;));
}
</code></pre>

What's the most efficient way to trim the suffix in Java, like this:

<pre><code>title part1.txt
title part2.html
=&gt;
title part1
title part2
</code></pre>

How do I trim a file extension from a String in Java?

Java

在Java中修剪后缀的最有效方法是什么，如下所示：title part1.txttitle part2.html=>title part1title part2

问如何在Java中从字符串中裁剪文件扩展名？
EN

回答 17

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问如何在Java中从字符串中裁剪文件扩展名？EN

回答 17

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问如何在Java中从字符串中裁剪文件扩展名？
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