java操作大文件复制

package com.dingwang.File;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;

/**
 * 类FileToFile.java的实现描述：TODO 类实现描述 <br>
 * 将一个文件中的内容写到另一个文件
 * 
 * @author wangding_91@163.com 2016年2月5日 上午11:55:26
 */
public class FileToFile {

    private static final int DEFAULT_BUFFER = 3 * 1024;

    /**
     * 利用通道copy文件
     * 
     * @param source
     * @param target
     */
    public void transfer(File source, File target) {

        FileInputStream in = null;
        FileOutputStream out = null;
        if (!source.exists() || !source.isFile()) {
            throw new IllegalArgumentException("file not exsits!");
        }

        if (target.exists()) {
            target.delete();
        }

        try {
            target.createNewFile();
            in = new FileInputStream(source);
            out = new FileOutputStream(target);
            FileChannel inChannel = in.getChannel();
            WritableByteChannel outChannel = out.getChannel();
            inChannel.transferTo(0, inChannel.size(), outChannel);
            inChannel.close();
            outChannel.close();
            in.close();
            out.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 传统的输入输出流copy文件
     * 
     * @param source
     * @param target
     */
    public void transfer2(File source, File target) {
        InputStream in = null;
        OutputStream out = null;
        if (!source.exists() || !source.isFile()) {
            throw new IllegalArgumentException("file not exsits!");
        }

        if (target.exists()) {
            target.delete();
        }

        byte[] buffer = new byte[DEFAULT_BUFFER];
        int n = 0;

        try {
            target.createNewFile();
            in = new BufferedInputStream(new FileInputStream(source));
            out = new BufferedOutputStream(new FileOutputStream(target));
            while ((n = in.read(buffer)) != -1) {
                out.write(buffer, 0, n);
            }
            out.flush();
            in.close();
            out.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package com.dingwang.file;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.junit.Test;

import com.dingwang.File.FileToFile;

/**
 * 类FileToFileTest.java的实现描述：TODO 类实现描述
 * 
 * @author wangding_91@163.com 2016年2月5日 下午12:05:58
 */
public class FileToFileTest {

    //    @Test
    public void FileToFile() {
        String date = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
        String username = System.getProperty("user.name");
        FileToFile f = new FileToFile();
        File source = new File("E:\\生产问题查询\\policy_biz_id_2015.dat");
        String targetFileName = "E:\\生产问题查询\\target_" + username + "_" + date + ".dat";
        File target = new File(targetFileName);
        Long start = System.currentTimeMillis();
        f.transfer(source, target);
        System.out.println("耗时=" + ((System.currentTimeMillis() - start)) + "ms");
    }

    @Test
    public void transfer2() {
        String date = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
        String username = System.getProperty("user.name");
        FileToFile f = new FileToFile();
        //E:\\生产问题查询\\policy_biz_id_2015.dat
        File source = new File("E:\\生产问题查询\\policy_biz_id_2015.dat");
        String targetFileName = "E:\\生产问题查询\\target_" + username + "_" + date + ".dat";
        File target = new File(targetFileName);
        Long start = System.currentTimeMillis();
        f.transfer2(source, target);
        System.out.println("耗时=" + ((System.currentTimeMillis() - start)) + "ms");
    }
}