Java 从 URL 获取文件名

Get file name from URL

提问by Sietse

In Java, given a java.net.URLor a Stringin the form of http://www.example.com/some/path/to/a/file.xml, what is the easiest way to get the file name, minus the extension? So, in this example, I'm looking for something that returns "file".

在 Java 中，给定 ajava.net.URL或 aString的形式http://www.example.com/some/path/to/a/file.xml，获取文件名的最简单方法是什么，减去扩展名？所以，在这个例子中，我正在寻找返回"file".

I can think of several ways to do this, but I'm looking for something that's easy to read and short.

我可以想到几种方法来做到这一点，但我正在寻找易于阅读和简短的东西。

采纳答案by Adrian B.

Instead of reinventing the wheel, how about using Apache commons-io:

与其重新发明轮子，不如使用 Apache commons-io：

import org.apache.commons.io.FilenameUtils;

public class FilenameUtilTest {

    public static void main(String[] args) throws Exception {
        URL url = new URL("http://www.example.com/some/path/to/a/file.xml?foo=bar#test");

        System.out.println(FilenameUtils.getBaseName(url.getPath())); // -> file
        System.out.println(FilenameUtils.getExtension(url.getPath())); // -> xml
        System.out.println(FilenameUtils.getName(url.getPath())); // -> file.xml
    }

}

回答by tehvan

This should about cut it (i'll leave the error handling to you):

这应该关于削减它（我会把错误处理留给你）：

int slashIndex = url.lastIndexOf('/');
int dotIndex = url.lastIndexOf('.', slashIndex);
String filenameWithoutExtension;
if (dotIndex == -1) {
  filenameWithoutExtension = url.substring(slashIndex + 1);
} else {
  filenameWithoutExtension = url.substring(slashIndex + 1, dotIndex);
}

回答by Sietse

I've come up with this:

我想出了这个：

String url = "http://www.example.com/some/path/to/a/file.xml";
String file = url.substring(url.lastIndexOf('/')+1, url.lastIndexOf('.'));

回答by Real Red.

String fileName = url.substring( url.lastIndexOf('/')+1, url.length() );

String fileNameWithoutExtn = fileName.substring(0, fileName.lastIndexOf('.'));

回答by Ricardo Felgueiras

import java.io.*;

导入 java.io.*;

import java.net.*;

public class ConvertURLToFileName{


   public static void main(String[] args)throws IOException{
   BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
   System.out.print("Please enter the URL : ");

   String str = in.readLine();


   try{

     URL url = new URL(str);

     System.out.println("File : "+ url.getFile());
     System.out.println("Converting process Successfully");

   }  
   catch (MalformedURLException me){

      System.out.println("Converting process error");

 }

I hope this will help you.

我希望这能帮到您。

回答by Thorbj?rn Ravn Andersen

Create an URL object from the String. When first you have an URL object there are methods to easily pull out just about any snippet of information you need.

从字符串创建一个 URL 对象。当您第一次拥有一个 URL 对象时，有一些方法可以轻松提取您需要的任何信息片段。

I can strongly recommend the Javaalmanac web site which has tons of examples, but which has since moved. You might find http://exampledepot.8waytrips.com/egs/java.io/File2Uri.htmlinteresting:

我强烈推荐 Javaalmanac 网站，该网站有大量示例，但此后已迁移。您可能会发现http://exampledepot.8waytrips.com/egs/java.io/File2Uri.html很有趣：

// Create a file object
File file = new File("filename");

// Convert the file object to a URL
URL url = null;
try {
    // The file need not exist. It is made into an absolute path
    // by prefixing the current working directory
    url = file.toURL();          // file:/d:/almanac1.4/java.io/filename
} catch (MalformedURLException e) {
}

// Convert the URL to a file object
file = new File(url.getFile());  // d:/almanac1.4/java.io/filename

// Read the file contents using the URL
try {
    // Open an input stream
    InputStream is = url.openStream();

    // Read from is

    is.close();
} catch (IOException e) {
    // Could not open the file
}

回答by bobince

andy's answer redone using split():

安迪的回答使用 split() 重做：

Url u= ...;
String[] pathparts= u.getPath().split("\/");
String filename= pathparts[pathparts.length-1].split("\.", 1)[0];

回答by Mike

public static String getFileName(URL extUrl) {
        //URL: "http://photosaaaaa.net/photos-ak-snc1/v315/224/13/659629384/s659629384_752969_4472.jpg"
        String filename = "";
        //PATH: /photos-ak-snc1/v315/224/13/659629384/s659629384_752969_4472.jpg
        String path = extUrl.getPath();
        //Checks for both forward and/or backslash 
        //NOTE:**While backslashes are not supported in URL's 
        //most browsers will autoreplace them with forward slashes
        //So technically if you're parsing an html page you could run into 
        //a backslash , so i'm accounting for them here;
        String[] pathContents = path.split("[\\/]");
        if(pathContents != null){
            int pathContentsLength = pathContents.length;
            System.out.println("Path Contents Length: " + pathContentsLength);
            for (int i = 0; i < pathContents.length; i++) {
                System.out.println("Path " + i + ": " + pathContents[i]);
            }
            //lastPart: s659629384_752969_4472.jpg
            String lastPart = pathContents[pathContentsLength-1];
            String[] lastPartContents = lastPart.split("\.");
            if(lastPartContents != null && lastPartContents.length > 1){
                int lastPartContentLength = lastPartContents.length;
                System.out.println("Last Part Length: " + lastPartContentLength);
                //filenames can contain . , so we assume everything before
                //the last . is the name, everything after the last . is the 
                //extension
                String name = "";
                for (int i = 0; i < lastPartContentLength; i++) {
                    System.out.println("Last Part " + i + ": "+ lastPartContents[i]);
                    if(i < (lastPartContents.length -1)){
                        name += lastPartContents[i] ;
                        if(i < (lastPartContentLength -2)){
                            name += ".";
                        }
                    }
                }
                String extension = lastPartContents[lastPartContentLength -1];
                filename = name + "." +extension;
                System.out.println("Name: " + name);
                System.out.println("Extension: " + extension);
                System.out.println("Filename: " + filename);
            }
        }
        return filename;
    }

回答by Campa

public String getFileNameWithoutExtension(URL url) {
    String path = url.getPath();

    if (StringUtils.isBlank(path)) {
        return null;
    }
    if (StringUtils.endsWith(path, "/")) {
        //is a directory ..
        return null;
    }

    File file = new File(url.getPath());
    String fileNameWithExt = file.getName();

    int sepPosition = fileNameWithExt.lastIndexOf(".");
    String fileNameWithOutExt = null;
    if (sepPosition >= 0) {
        fileNameWithOutExt = fileNameWithExt.substring(0,sepPosition);
    }else{
        fileNameWithOutExt = fileNameWithExt;
    }

    return fileNameWithOutExt;
}

回答by Leon

How about this:

这个怎么样：

String filenameWithoutExtension = null;
String fullname = new File(
    new URI("http://www.xyz.com/some/deep/path/to/abc.png").getPath()).getName();

int lastIndexOfDot = fullname.lastIndexOf('.');
filenameWithoutExtension = fullname.substring(0, 
    lastIndexOfDot == -1 ? fullname.length() : lastIndexOfDot);