[英]list all files from directories and subdirectories in Java
What would be the fastest way to list the names of files from 1000+ directories and sub-directories? 列出1000多个目录和子目录中文件名的最快方法是什么?
EDIT; 编辑; The current code I use is: 我使用的当前代码是:
import java.io.File;
public class DirectoryReader {
static int spc_count=-1;
static void Process(File aFile) {
spc_count++;
String spcs = "";
for (int i = 0; i < spc_count; i++)
spcs += " ";
if(aFile.isFile())
System.out.println(spcs + "[FILE] " + aFile.getName());
else if (aFile.isDirectory()) {
System.out.println(spcs + "[DIR] " + aFile.getName());
File[] listOfFiles = aFile.listFiles();
if(listOfFiles!=null) {
for (int i = 0; i < listOfFiles.length; i++)
Process(listOfFiles[i]);
} else {
System.out.println(spcs + " [ACCESS DENIED]");
}
}
spc_count--;
}
public static void main(String[] args) {
String nam = "D:/";
File aFile = new File(nam);
Process(aFile);
}
}
As this answer shows up on top of google, i'm adding a java 7 nio solution for listing all files and directories, it is takes about 80% less time on my system. 由于这个答案显示在google之上,我正在添加一个用于列出所有文件和目录的java 7 nio解决方案,它在我的系统上花费的时间减少了大约80%。
try {
Path startPath = Paths.get("c:/");
Files.walkFileTree(startPath, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir,
BasicFileAttributes attrs) {
System.out.println("Dir: " + dir.toString());
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
System.out.println("File: " + file.toString());
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFileFailed(Path file, IOException e) {
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
e.printStackTrace();
}
这看起来很好(递归遍历目录)瓶颈将是你需要做的所有文件i / o,优化你的Java将不会显示任何真正的改进。
The only improvement is to get rid of static spc_count
and pass spcs
string as a parameter to Process. 唯一的改进是摆脱static spc_count
并将spcs
字符串作为参数传递给Process。
public static void main(String[] args) {
String nam = "D:/";
File aFile = new File(nam);
Process("", aFile);
}
And when doing recursive call, do 在做递归调用时,做
static void Process( String spcs, File aFile) {
...
Process(spcs + " ", listOfFiles[i]);
...
}
This way you can call this method from more than 1 thread. 这样,您可以从多个线程调用此方法。
在Java 7引入新的java.nio.file类(如DirectoryStream
)之前,我担心你已经拥有的将是最快的。
If you're open to using a 3rd party library, check out javaxt-core . 如果您愿意使用第三方库,请查看javaxt-core 。 It includes a multi-threaded recursive directory search that should be faster than iterating through one directory at a time. 它包括一个多线程递归目录搜索,它应该比一次迭代一个目录更快。 There are some examples here: 这里有一些例子:
http://www.javaxt.com/javaxt-core/io/Directory/Recursive_Directory_Search http://www.javaxt.com/javaxt-core/io/Directory/Recursive_Directory_Search
I have written a much simpler code....Try this... It will show every folder, subfolders and files... 我写了一个更简单的代码....尝试这个...它将显示每个文件夹,子文件夹和文件...
int Files=0,Directory=0,HiddenFiles=0,HiddenDirectory=0;
public void listf(String directoryName){
File file=new File(directoryName);
File[] fileList=file.listFiles();
if(fileList!=null){
for(int i=0;i<fileList.length;i++){
if(fileList[i].isHidden()){
if(fileList[i].isFile())
{
System.out.println(fileList[i]);
HiddenFiles++;
}
else{
listf(String.valueOf(fileList[i]));
HiddenDirectory++;
}
}
else if (fileList[i].isFile()) {
//System.out.println(fileList[i]);
Files++;
}
else if(fileList[i].isDirectory()){
Directory++;
listf(String.valueOf(fileList[i]));
}
}
}
}
public void Numbers(){
System.out.println("Files: "+Files+" HiddenFiles: "+HiddenFiles+"Hidden Directories"+HiddenDirectory+" Directories: "+Directory);`
}
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