Apache-Commons IO

工具類一共6個:

org.apache.commons.io.filefilter.FileFilterUtils

org.apache.commons.io.

• EndianUtils
• FilenameUtils
• FileSystemUtils
• FileUtils
• IOUtils

普通地讀取一個網頁的源代碼的代碼可能以下

InputStream in = new URL( "http://laoyu.info" ).openStream();
 try {
   InputStreamReader inR = new InputStreamReader( in );
   BufferedReader buf = new BufferedReader( inR );
   String line;
   while ( ( line = buf.readLine() ) != null ) {
     System.out.println( line );
   }
 } finally {
   in.close();
 }

使用了Commons IO,則能夠大大簡化代碼.以下:

InputStream in = new URL( "http://laoyu.info" ).openStream();
 try {
   System.out.println( IOUtils.toString( in ) );
 } finally {
   IOUtils.closeQuietly(in);
 }

Commons IO裏的經常使用類

FileUtils包含了文件操做的相關方法.
下面的代碼用於讀取磁盤上的某個文件:

File file = new File("c:/test.txt");
List lines = FileUtils.readLines(file, "UTF-8");

FileSystemUtils 能夠得到指定磁盤路徑的可用空間

long freeSpace = FileSystemUtils.freeSpace("d:/");

文件複製代碼:

File src = new File("src.txt");
File dest = new File("dest.txt");
FileUtils.copyFile(src, dest);

方便地下載文件到本地

InputStream in = new
URL("http://www.baidu.com/img/baidu_logo.gif").openStream();
		byte [] gif = IOUtils.toByteArray(in);
		//IOUtils.write(gif,new FileOutputStream(new File("c:/test.gif")));
		FileUtils.writeByteArrayToFile(new File("c:/test.gif"),gif);
		IOUtils.closeQuietly(in);