java文件分割和合并

package search;



import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;



public class Split {

    

    /**每个小文件大小*/

    static final int SIZE = 1024*1024*5;

    /**需要分割的文件*/

    static final String SOURCE = "E:/t_question.sql";

    /**分割后输出的目录*/

    static final String SOURCE_OUT = "E:/test/";

    /**合并后的文件*/

    static final String DST = "G:/quesion.sql";



    public static void main(String[] args) throws IOException{

        split();

    }

    /**

     * 文件分割

     * @throws IOException

     */

    public static void split() throws IOException{



        File file = new File(SOURCE);

        FileInputStream raf = new FileInputStream(file);

        FileChannel fc = raf.getChannel();

        long fileSize = fc.size();

        

        int count = (int) (fileSize/SIZE);

        ByteBuffer dst = ByteBuffer.allocate(SIZE);

        for(int i=0 ; i <=count  ; i++){

            FileOutputStream fs = new FileOutputStream(new File(SOURCE_OUT+i));

            if(i!=count){

                fc.read(dst,SIZE*i);

                fs.write(dst.array());

            }else{

                fileSize = fileSize -SIZE*count;

                System.out.println(fileSize);

                ByteBuffer dstTail = ByteBuffer.allocate((int) fileSize);

                fs.write(dstTail.array());

            }

            fs.flush();

            dst.clear();

        }

    

    }

    

    /**

     * 合并文件

     * @throws Exception

     */

    public static void merge()throws Exception{

        File parentFile = new File(SOURCE_OUT);

        File fileDst = new File(DST);

        FileChannel fs =  new FileOutputStream(fileDst, true).getChannel();

        try{

             for(File file :parentFile.listFiles()){

                 FileChannel fc = new FileInputStream(file).getChannel();

                 ByteBuffer by = ByteBuffer.allocate((int) fc.size());

                 fc.read(by);

                 by.position(0);

                 fs.write(by);

                 

             }

        }finally{

            fs.close();

        }

    }

}