javase文件切割及融合

package com.split;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class FileSplit {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        //String file = "D:\arch\d.jpg";
        String file="D:\arch\b.txt";
        split(file);
        String s1="D:\arch\b.txtpart-0";
        String s2="D:\arch\b.txtpart-1";
        String s3="D:\arch\b.txtpart-2";
        fuse(s1,s2,s3);

    }
/**
 * 文件融合
 * @param srcFile
 */
public static void fuse(String... srcFile ){
    for (String string : srcFile) {
        fusion(string);
    }
}
    private static void fusion(String file) {
        File f=new File(file);
        FileInputStream fis=null;
        FileOutputStream fos=null;
        try {
            if(f.exists()){
                if(f.isFile()){
                    fis=new FileInputStream(f);
                    //string="D:\arch\b.txtpart-0"
                    String srcPath=f.getAbsolutePath();
                    String sep="";
                    if(srcPath.contains("\")){
                        sep="\";
                    }
                    int index=srcPath.lastIndexOf(sep);
                    
                    //String s=srcPath.substring(0, (srcPath.length()-6));
                    //获取最后一个名字的字符串
                    String s=srcPath.substring(0, index+f.getName().length());
                    fos=new FileOutputStream(new File(s),true);
                    byte[] buf=new byte[1024];
                    int len=0;
                    while((len=fis.read(buf))!=-1){
                        fos.write(buf, 0, len);
                        fos.close();
                    }
                }
            }
            fis.close();
        } catch (Exception e) {
            // TODO: handle exception
        }
}
/**
 * 文件的切割
 */
    public static void split(String srcfile) {

        File f = new File(srcfile);
        FileOutputStream fos = null;
        try {
            FileInputStream fis = new FileInputStream(f);
            // 获取文件大小
            int len = (int) f.length();
            // 切割块数
            int blocks = 3;
            // 每块的大小
            int blocksSize = len / blocks;
            int len0 = 0;
            byte[] buf = new byte[1024];
            for (int i = 0; i < blocks; i++) {
                //根据源目录创建目标文件对象
                fos = new FileOutputStream(new File(f.getParent(), f.getName() + "part-" + i));
                // 如果是最后一块
                if (i == (blocks - 1)) {
                    while ((len0 = fis.read(buf)) != -1) {
                        fos.write(buf, 0, len0);
                    }
                    fos.close();
                }
                // 不是最后一块
                else {
                    // 不足缓冲区
                    if (blocksSize <=buf.length) {
                        buf = new byte[blocksSize];
                        fis.read(buf);
                        fos.write(buf);
                        fos.close();
                    }
                    // 超过缓冲区
                    else {
                        int count = blocksSize / buf.length;
                        for (int j = 0; j < count; j++) {
                            // 最后一次读取
                            if (j == (count - 1)) {
                                if(blocksSize%buf.length !=0){
                                    buf = new byte[buf.length + (blocksSize % buf.length)];
                                    fis.read(buf);
                                    fos.write(buf);
                                    fos.close();
                                }
                            } 
                            else {
                                fis.read(buf);
                                fos.write(buf);
                            }
                        }
                    }
                }
            }
            fis.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}