java学习之IO文件分割

package om.gh.homework;
import java.io.*;
/**
 * 实现分割文件;
 * @param file
 */
public class HomeWork {
    /**
     * @param src
     *            要分割的文件路径
     * @param n
     *            每个文件的大小以mb为单位
     * @param desc
     *            分割的文件存放路径
     * @throws FileNotFoundException
     */
    public static void filesplit(File src, int mb, File desc)
            throws FileNotFoundException {
        // 判断文件路径
        if (src.exists() && src.isFile() && desc.isDirectory()) {
            int fileSize = mb * 1024 * 1024;
            int n;
            // 判断要分割文件的个数n;
            if (src.length() % fileSize == 0)
                n = (int) (src.length() / fileSize);
            else
                n = (int) (src.length() / fileSize) + 1;
            try {
                InputStream is = new FileInputStream(src);
                BufferedInputStream bis = new BufferedInputStream(is);
                for (int i = 0; i < n; i++) {// 循环写入每个文件;
                    byte[] b = new byte[fileSize];
                    String newfile = desc.getPath() + File.separator
                            + src.getName()+"_"+ i + ".dat";
                    BufferedOutputStream bos = new BufferedOutputStream(//缓存流
                            new FileOutputStream(newfile));
                    int len = -1;
                    int count=0;
                    while ((len = bis.read(b)) != -1) {
                        bos.write(b,0,len);
                        count+=len;
                        bos.flush();
                        if(count>=fileSize)break;
                    }
                    bos.close();
                }
                bis.close();
                is.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            throw new FileNotFoundException("文件不存在或者参数错误！");
        }
    }
    
    public static void main(String[] args) {
        File src = new File("F:\电影\万万没想到.mp4");//要分割的目标文件
        File desc = new File("f:\视频\");//分割完存放的路径
        int mb = 500;// 每个文件大小，以Mb为单位；
        System.out.println("开始分割...");
        try {
            filesplit(src, mb, desc);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.out.println("分割完成！");
    }
}

package om.gh.homework;
import java.io.*;
/**
 * 把分割后的文件合并
 * 
 * @author ganhang
 * 
 */
public class Homework2 {
    /**
     * 
     * @param desc
     *            合成后的文件路径
     * @param src
     *            要合成的文件列表
     */
    public static void merge(File desc, File... src) {
        try {
            String filename = src[0].getName().substring(0,
                    src[0].getName().lastIndexOf("_"));
            File newfile = new File(desc.getPath() + File.separator + filename);
            OutputStream os = new FileOutputStream(newfile);
            BufferedOutputStream bos = new BufferedOutputStream(os);
            for (int i = 0; i < src.length; i++) {
                BufferedInputStream bis = new BufferedInputStream(
                        new FileInputStream(src[i]));
                byte[] b = new byte[1024 * 1024];
                int len = -1;
                while ((len = bis.read(b)) != -1) {
                    bos.write(b, 0, len);
                    bos.flush();
                }
                bis.close();
            }
            bos.close();
            os.close();
            System.out.println("合成成功！");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        File desc=new File("f:\视频\");
        File [] src={
                new File("f:\视频\万万没想到.mp4_0.dat"),
                new File("f:\视频\万万没想到.mp4_1.dat"),
                new File("f:\视频\万万没想到.mp4_2.dat"),
                new File("f:\视频\万万没想到.mp4_3.dat")
        };
        System.out.println("开始合成...");
        merge(desc,src);
    }
}