Commons IO是apache的一個開源的工具包,封裝了IO操作的相關類,使用Commons IO可以很方便的讀寫檔案,

FileUtils 中提供了許多設計檔案操作的 已封裝好的方法。

IOUtils 則是提供了讀寫檔案的方法。

File src = new File("G:/2012/portal/login.jsp");
File tar = new File("G:/2012/portal/loginZs.jsp");
File tarDir = new File("G:/2012/portal/center/");

FileUtils.copyFile(src,tar);//複製檔案
FileUtils.copyFileToDirectory(src, tarDir);//複製檔案到指定資料夾
 

讀取檔案：

// by FileUtils  
List<String> lines = FileUtils.readLines(file, "UTF-8");  

// by IOUtils  
List<String> lines = IOUtils.readLines(new FileInputStream(file), "UTF-8");  

寫入檔案：

// by FileUtils  
FileUtils.writeLines(file, "UTF-8", lines);  

// by IOUtils  
IOUtils.writeLines(lines
 
, null, new FileOutputStream(file));  

案例：

public class IoTest {  

    /** 
     * @param args 
     */  
    public static void main(String[] args) throws Exception {  
        // 輸入流複製到 輸出流 
        Writer write = new FileWriter("c:\\kk.dat");  

        InputStream ins = new FileInputStream(new File("c:\\text.txt"
 
));  

        IOUtils.copy(ins, write);  
        write.close();  

        ins.close();  

        //文字寫入指定檔案 
        String name = "my name is panxiuyan";  

        File file =  new File("c:\\name.txt");  

        FileUtils.writeStringToFile(file, name);  

        //將輸入流轉換成文字 

        URL url = new URL("http://www.dimurmill.com");  

        InputStream ins = url.openStream();  

        String contents = IOUtils.toString(ins,"UTF-8");  
        System.out.println( "Slashdot: " + contents );  

            //關閉相關流
             File file = null;  

        InputStream ins = null;  
        try{  
            file = new File("C:\\Test.java");  

            ins = new FileInputStream(file);  
        }catch(Exception e){  
            e.printStackTrace();  
        }finally{  
            IOUtils.closeQuietly(ins);  
        }  


        }

        //檔案複製
        File srcfile = new File("c:\\Test.java");    
        File destfile = new File("c:\\Test.java.bak");    
        FileUtils.copyFile(srcfile, destfile);    

        //檔案複製指定的目錄 
        File srcfile = new File("c:\\Test.java");    
        File destDir = new File("D:\\");  
        FileUtils.copyFileToDirectory(srcfile, destDir);  

        //網路流儲存為檔案
    URL url = new URL("http://www.163.com");   
        File file = new File("c:\\163.html");      
        FileUtils.copyURLToFile(url, file);  

        //檔案目錄操作 
        File dir = new File("c:\\test");  
        FileUtils.cleanDirectory(dir);//清空目錄下的檔案  
        FileUtils.deleteDirectory(dir);//刪除目錄和目錄下的檔案 

        //目錄大小  
        long size = FileUtils.sizeOfDirectory(dir);  

        //目錄操作
        File testFile = new File( "testFile.txt" );  
        //如果不存在,新建  
        // 如果存在,修改檔案修改時間  
        FileUtils.touch( testFile );  
        //記錄流的讀取寫入位元組數 
        File test = new File( "test.dat" );  
        //輸出流的統計  
    CountingOutputStream countStream = null;  
    //輸入流的統計  
    //CountingInputStream countStream = null;  
    try {  
            FileOutputStream fos = new FileOutputStream( test );          
        countStream = new CountingOutputStream( fos );  
        countStream.write( "Hello".getBytes( ) );  
        } catch( IOException ioe ) {  
            System.out.println( "Error writing bytes to file." );  
        } finally {       
            IOUtils.closeQuietly( countStream );    
        }  

        if( countStream != null ) {  
             int bytesWritten = countStream.getCount( );  
             System.out.println( "Wrote " + bytesWritten + " bytes to test.dat" );  
        }  

        //相同的內容寫入不同的文字 
        File test1 = new File("split1.txt");  
                File test2 = new File("split2.txt");  
        OutputStream outStream = null;  
        try {  
            FileOutputStream fos1 = new FileOutputStream( test1 );  
            FileOutputStream fos2 = new FileOutputStream( test2 );  
            //包含不同的文字  
            outStream = new TeeOutputStream( fos1, fos2 );  
            outStream.write( "One Two Three, Test".getBytes( ) );  
            outStream.flush( );       
        } catch( IOException ioe ) {      
            System.out.println( "Error writing to split output stream" );         
        } finally {           
            IOUtils.closeQuietly( outStream );            
            } 
         }  

}