blocks|key|995577|text|它是一棵树，所以递归是您的选择:从父目录开始，调用该方法以获得子文件的数组。遍历子数组。如果当前值是一个目录，则将其传递给方法的递归调用。如果没有，则对叶文件进行适当的处理。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995578|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|$]]

It's a tree, so recursion is your friend: start with the parent directory and call the method to get an array of child Files. Iterate through the child array. If the current value is a directory, pass it to a recursive call of your method. If not, process the leaf file appropriately.

blocks|key|995643|text|如前所述，这是一个递归问题。具体地说，您可能需要查看|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995644|listFiles()+|code-block|syntax|javascript|995645|在java+File+API+here中。它返回一个目录中所有文件的数组。将其与|offset|length|995646|isDirectory()|995647|看看是否需要进一步递归是一个很好的开始。|995648|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/8/docs/api/java/io/File.html^0|0|0|F|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@$I|Z|J|10|1|11]]|A|$]]|$1|K|3|L|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

As noted, this is a recursion problem. In particular, you may want to look at

<pre><code>listFiles() 
</code></pre>

In the java File API <a href="http://docs.oracle.com/javase/8/docs/api/java/io/File.html" rel="nofollow noreferrer">here</a>. It returns an array of all the files in a directory. Using this along with 

<pre><code>isDirectory()
</code></pre>

to see if you need to recurse further is a good start.

blocks|key|1210054|text|您可以使用File#isDirectory()来测试给定的文件(路径)是否为目录。如果这是true，那么您只需使用其File#listFiles()结果再次调用相同的方法。这称为recursion。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1210055|这是一个基本的启动示例：|1210056|package+com.stackoverflow.q3154488;

import+java.io.File;

public+class+Demo+{

++++public+static+void+main(String...+args)+{
++++++++File+dir+=+new+File("/path/to/dir");
++++++++showFiles(dir.listFiles());
++++}

++++public+static+void+showFiles(File[]+files)+{
++++++++for+(File+file+:+files)+{
++++++++++++if+(file.isDirectory())+{
++++++++++++++++System.out.println("Directory:+"+%2B+file.getAbsolutePath());
++++++++++++++++showFiles(file.listFiles());+//+Calls+same+method+again.
++++++++++++}+else+{
++++++++++++++++System.out.println("File:+"+%2B+file.getAbsolutePath());
++++++++++++}
++++++++}
++++}
}|code-block|syntax|javascript|1210057|请注意，当树的深度超过StackOverflowError的堆栈时，这对JVM很敏感。如果您已经在使用Java8或更新版本，那么最好使用利用tail+recursion的Files#walk()|1210058|package+com.stackoverflow.q3154488;

import+java.io.File;
import+java.nio.file.Files;
import+java.nio.file.Path;
import+java.nio.file.Paths;

public+class+DemoWithJava8+{

++++public+static+void+main(String...+args)+throws+Exception+{
++++++++Path+dir+=+Paths.get("/path/to/dir");
++++++++Files.walk(dir).forEach(path+->+showFile(path.toFile()));
++++}

++++public+static+void+showFile(File+file)+{
++++++++if+(file.isDirectory())+{
++++++++++++System.out.println("Directory:+"+%2B+file.getAbsolutePath());
++++++++}+else+{
++++++++++++System.out.println("File:+"+%2B+file.getAbsolutePath());
++++++++}
++++}
}|1210059|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/6/docs/api/java/io/File.html#isDirectory%2528%2529|1|https://docs.oracle.com/javase/6/docs/api/java/io/File.html#listFiles%2528%2529|2|http://en.wikipedia.org/wiki/Recursion|3|https://docs.oracle.com/javase/6/docs/api/java/lang/StackOverflowError.html|4|https://en.wikipedia.org/wiki/Tail_call|5|https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#walk-java.nio.file.Path-java.nio.file.FileVisitOption...-^0|5|I|19|4|1M|G|5|I|0|1M|G|1|2H|9|2|0|0|0|B|I|2D|C|B|I|3|1Y|E|4|2D|C|5|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@$9|19|A|1A|B|C]|$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]]|D|@$9|1F|A|1G|1|1H]|$9|1I|A|1J|1|1K]|$9|1L|A|1M|1|1N]]|E|$]]|$1|F|3|G|5|6|7|1O|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1P|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1Q|8|@$9|1R|A|1S|B|C]|$9|1T|A|1U|B|C]]|D|@$9|1V|A|1W|1|1X]|$9|1Y|A|1Z|1|20]|$9|21|A|22|1|23]]|E|$]]|$1|O|3|P|5|J|7|24|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|25|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]|10|$5|T|U|V|E|$W|11]]|12|$5|T|U|V|E|$W|13]]|14|$5|T|U|V|E|$W|15]]|16|$5|T|U|V|E|$W|17]]]]

You can use <a href="https://docs.oracle.com/javase/6/docs/api/java/io/File.html#isDirectory%28%29" rel="noreferrer"><code>File#isDirectory()</code></a> to test if the given file (path) is a directory. If this is <code>true</code>, then you just call the same method again with its <a href="https://docs.oracle.com/javase/6/docs/api/java/io/File.html#listFiles%28%29" rel="noreferrer"><code>File#listFiles()</code></a> outcome. This is called <a href="http://en.wikipedia.org/wiki/Recursion" rel="noreferrer">recursion</a>.
Here's a basic kickoff example:
<pre class="lang-java prettyprint-override"><code>package com.stackoverflow.q3154488;

import java.io.File;

public class Demo {

 public static void main(String... args) {
 File dir = new File(&quot;/path/to/dir&quot;);
 showFiles(dir.listFiles());
 }

 public static void showFiles(File[] files) {
 for (File file : files) {
 if (file.isDirectory()) {
 System.out.println(&quot;Directory: &quot; + file.getAbsolutePath());
 showFiles(file.listFiles()); // Calls same method again.
 } else {
 System.out.println(&quot;File: &quot; + file.getAbsolutePath());
 }
 }
 }
}
</code></pre>
Note that this is sensitive to <a href="https://docs.oracle.com/javase/6/docs/api/java/lang/StackOverflowError.html" rel="noreferrer"><code>StackOverflowError</code></a> when the tree is deeper than the JVM's stack can hold. If you're already on Java 8 or newer, then you'd better use <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#walk-java.nio.file.Path-java.nio.file.FileVisitOption...-" rel="noreferrer"><code>Files#walk()</code></a> instead which utilizes <a href="https://en.wikipedia.org/wiki/Tail_call" rel="noreferrer">tail recursion</a>:
<pre class="lang-java prettyprint-override"><code>package com.stackoverflow.q3154488;

import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class DemoWithJava8 {

 public static void main(String... args) throws Exception {
 Path dir = Paths.get(&quot;/path/to/dir&quot;);
 Files.walk(dir).forEach(path -&gt; showFile(path.toFile()));
 }

 public static void showFile(File file) {
 if (file.isDirectory()) {
 System.out.println(&quot;Directory: &quot; + file.getAbsolutePath());
 } else {
 System.out.println(&quot;File: &quot; + file.getAbsolutePath());
 }
 }
}
</code></pre>

blocks|key|995760|text|如果你使用的是Java1.7，你可以使用java.nio.file.Files.walkFileTree(...)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|995761|例如：|995762|public+class+WalkFileTreeExample+{

++public+static+void+main(String[]+args)+{
++++Path+p+=+Paths.get("/usr");
++++FileVisitor<Path>+fv+=+new+SimpleFileVisitor<Path>()+{
++++++@Override
++++++public+FileVisitResult+visitFile(Path+file,+BasicFileAttributes+attrs)
++++++++++throws+IOException+{
++++++++System.out.println(file);
++++++++return+FileVisitResult.CONTINUE;
++++++}
++++};

++++try+{
++++++Files.walkFileTree(p,+fv);
++++}+catch+(IOException+e)+{
++++++e.printStackTrace();
++++}
++}

}|code-block|syntax|javascript|995763|如果您使用的是Java8，则可以将流接口与java.nio.file.Files.walk(...)一起使用|995764|public+class+WalkFileTreeExample+{

++public+static+void+main(String[]+args)+{
++++try+(Stream<Path>+paths+=+Files.walk(Paths.get("/usr")))+{
++++++paths.forEach(System.out::println);
++++}+catch+(IOException+e)+{
++++++e.printStackTrace();
++++}
++}

}|995765|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#walkFileTree(java.nio.file.Path,%2520java.nio.file.FileVisitor))|1|https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#walk-java.nio.file.Path-java.nio.file.FileVisitOption...-^0|K|11|K|11|0|0|0|0|L|T|L|T|1|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|6|7|16|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|17|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@$9|1B|A|1C|1|1D]]|E|$]]|$1|O|3|P|5|J|7|1E|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]]]

If you are using Java 1.7, you can use <a href="https://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#walkFileTree(java.nio.file.Path,%20java.nio.file.FileVisitor)" rel="noreferrer"><code>java.nio.file.Files.walkFileTree(...)</code></a>.

For example:

<pre><code>public class WalkFileTreeExample {

 public static void main(String[] args) {
 Path p = Paths.get("/usr");
 FileVisitor&lt;Path&gt; fv = new SimpleFileVisitor&lt;Path&gt;() {
 @Override
 public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
 throws IOException {
 System.out.println(file);
 return FileVisitResult.CONTINUE;
 }
 };

 try {
 Files.walkFileTree(p, fv);
 } catch (IOException e) {
 e.printStackTrace();
 }
 }

}
</code></pre>

If you are using Java 8, you can use the stream interface with <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#walk-java.nio.file.Path-java.nio.file.FileVisitOption...-" rel="noreferrer"><code>java.nio.file.Files.walk(...)</code></a>:

<pre><code>public class WalkFileTreeExample {

 public static void main(String[] args) {
 try (Stream&lt;Path&gt; paths = Files.walk(Paths.get("/usr"))) {
 paths.forEach(System.out::println);
 } catch (IOException e) {
 e.printStackTrace();
 }
 }

}
</code></pre>

blocks|key|1210180|text|使用org.apache.commons.io.FileUtils|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1210181|File+file+=+new+File("F:/Lines");+++++++
Collection<File>+files+=+FileUtils.listFiles(file,+null,+true);+++++
for(File+file2+:+files){
++++System.out.println(file2.getName());++++++++++++
}+|code-block|syntax|javascript|1210182|如果不需要子目录中的文件，请使用false。|1210183|entityMap^0|2|V|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Using <code>org.apache.commons.io.FileUtils</code>

<pre><code>File file = new File("F:/Lines"); 
Collection&lt;File&gt; files = FileUtils.listFiles(file, null, true); 
for(File file2 : files){
 System.out.println(file2.getName()); 
} 
</code></pre>

Use false if you do not want files from sub directories.

blocks|key|995868|text|对于Java+7%2B，还有https://docs.oracle.com/javase/7/docs/api/java/nio/file/DirectoryStream.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|995869|取自Javadoc的示例：|995870|List<Path>+listSourceFiles(Path+dir)+throws+IOException+{
+++List<Path>+result+=+new+ArrayList<>();
+++try+(DirectoryStream<Path>+stream+=+Files.newDirectoryStream(dir,+"*.{c,h,cpp,hpp,java}"))+{
+++++++for+(Path+entry:+stream)+{
+++++++++++result.add(entry);
+++++++}
+++}+catch+(DirectoryIteratorException+ex)+{
+++++++//+I/O+error+encounted+during+the+iteration,+the+cause+is+an+IOException
+++++++throw+ex.getCause();
+++}
+++return+result;
}|code-block|syntax|javascript|995871|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/7/docs/api/java/nio/file/DirectoryStream.html^0|C|24|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

For Java 7+, there is also <a href="https://docs.oracle.com/javase/7/docs/api/java/nio/file/DirectoryStream.html" rel="noreferrer">https://docs.oracle.com/javase/7/docs/api/java/nio/file/DirectoryStream.html</a>

Example taken from the Javadoc:

<pre><code>List&lt;Path&gt; listSourceFiles(Path dir) throws IOException {
 List&lt;Path&gt; result = new ArrayList&lt;&gt;();
 try (DirectoryStream&lt;Path&gt; stream = Files.newDirectoryStream(dir, "*.{c,h,cpp,hpp,java}")) {
 for (Path entry: stream) {
 result.add(entry);
 }
 } catch (DirectoryIteratorException ex) {
 // I/O error encounted during the iteration, the cause is an IOException
 throw ex.getCause();
 }
 return result;
}
</code></pre>

blocks|key|995960|text|要加上@msandiford的答案，因为大多数时候，当遍历文件树时，你可能想要执行一个函数，作为一个目录或任何特定的文件被访问。如果你不愿意使用streams。可以实现以下被重写的方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995961|Files.walkFileTree(Paths.get(Krawl.INDEXPATH),+EnumSet.of(FileVisitOption.FOLLOW_LINKS),+Integer.MAX_VALUE,
++++new+SimpleFileVisitor<Path>()+{
++++++++@Override
++++++++public+FileVisitResult+preVisitDirectory(Path+dir,+BasicFileAttributes+attrs)
++++++++++++++++throws+IOException+{
++++++++++++++++//+Do+someting+before+directory+visit
++++++++++++++++return+FileVisitResult.CONTINUE;
++++++++}
++++++++@Override
++++++++public+FileVisitResult+visitFile(Path+file,+BasicFileAttributes+attrs)
++++++++++++++++throws+IOException+{
++++++++++++++++//+Do+something+when+a+file+is+visited
++++++++++++++++return+FileVisitResult.CONTINUE;
++++++++}
++++++++@Override
++++++++public+FileVisitResult+postVisitDirectory(Path+dir,+IOException+exc)
++++++++++++++++throws+IOException+{
++++++++++++++++//+Do+Something+after+directory+visit+
++++++++++++++++return+FileVisitResult.CONTINUE;
++++++++}
});|code-block|syntax|javascript|995962|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|$]]

To add with @msandiford answer, as most of the times when a file tree is walked u may want to execute a function as a directory or any particular file is visited. If u are reluctant to using streams. The following methods overridden can be implemented

<pre><code>Files.walkFileTree(Paths.get(Krawl.INDEXPATH), EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE,
 new SimpleFileVisitor&lt;Path&gt;() {
 @Override
 public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
 throws IOException {
 // Do someting before directory visit
 return FileVisitResult.CONTINUE;
 }
 @Override
 public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
 throws IOException {
 // Do something when a file is visited
 return FileVisitResult.CONTINUE;
 }
 @Override
 public FileVisitResult postVisitDirectory(Path dir, IOException exc)
 throws IOException {
 // Do Something after directory visit 
 return FileVisitResult.CONTINUE;
 }
});
</code></pre>

blocks|key|1210329|text|您还可以滥用File.list(FilenameFilter)+(及其变体)进行文件遍历。简短的代码，适用于早期的java版本，例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1210330|//+list+files+in+dir
new+File(dir).list(new+FilenameFilter()+{
++++public+boolean+accept(File+dir,+String+name)+{
++++++++String+file+=+dir.getAbsolutePath()+%2B+File.separator+%2B+name;
++++++++System.out.println(file);
++++++++return+false;
++++}
});|code-block|syntax|javascript|1210331|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 also misuse File.list(FilenameFilter) (and variants) for file traversal. Short code and works in early java versions, e.g:

<pre><code>// list files in dir
new File(dir).list(new FilenameFilter() {
 public boolean accept(File dir, String name) {
 String file = dir.getAbsolutePath() + File.separator + name;
 System.out.println(file);
 return false;
 }
});
</code></pre>

I need to get a list of all the files in a directory, including files in all the sub-directories. What is the standard way to accomplish directory iteration with Java?

How do I iterate through the files in a directory in Java?

Java

我需要获取一个目录中所有文件的列表，包括所有子目录中的文件。用Java完成目录迭代的标准方法是什么？

问如何在Java中遍历目录中的文件？
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