使用org.apache.commons.io.FileUtils,IOUtils;工具类操作文件

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);//复制文件
FileUtils.copyFileToDirectory(src, tarDir);//复制文件到指定文件夹

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);//复制文件
FileUtils.copyFileToDirectory(src, tarDir);//复制文件到指定文件夹

Commons IO是apache的一个开源的工具包,封装了IO操作的相关类,使用Commons IO可以很方便的读写文件,

FileUtils 中提供了许多设计文件操作的 已封装好的方法。

IOUtils 则是提供了读写文件的方法。

读取文件：

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

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

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

写入文件：

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

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

// by FileUtils  
FileUtils.writeLines(file, "UTF-8", lines);  
  
// by IOUtils  
IOUtils.writeLines(lines, null, new FileOutputStream(file));  

public class IoTest {

    /**
     * @param args
     */
    public static void main(String[] args) throws Exception {
        // 输入流复制到 输出流
        Writer write = new FileWriter("c:\\kk.dat");

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

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

        ins.close();

        //文本写入指定文件
        String name = "my name is panxiuyan";

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

        FileUtils.writeStringToFile(file, name);

        //将输入流转换成文本

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

        InputStream ins = url.openStream();

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

            //关闭相关流
             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);
        }


        }

        //文件复制
        File srcfile = new File("c:\\Test.java");
        File destfile = new File("c:\\Test.java.bak");
        FileUtils.copyFile(srcfile, destfile);

        //文件复制指定的目录
        File srcfile = new File("c:\\Test.java");
        File destDir = new File("D:\\");
        FileUtils.copyFileToDirectory(srcfile, destDir);

        //网络流保存为文件
    URL url = new URL("http://www.163.com");
        File file = new File("c:\\163.html");
        FileUtils.copyURLToFile(url, file);

        //文件目录操作
        File dir = new File("c:\\test");
        FileUtils.cleanDirectory(dir);//清空目录下的文件
        FileUtils.deleteDirectory(dir);//删除目录和目录下的文件

        //目录大小
        long size = FileUtils.sizeOfDirectory(dir);

        //目录操作
        File testFile = new File( "testFile.txt" );
        //如果不存在,新建
        // 如果存在,修改文件修改时间
        FileUtils.touch( testFile );
        //记录流的读取写入字节数
        File test = new File( "test.dat" );
        //输出流的统计
    CountingOutputStream countStream = null;
    //输入流的统计
    //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" );
        }

        //相同的内容写入不同的文本
        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 );
            //包含不同的文本
            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 );
            }
         }

}