文件的简单分割和合并

文件分割（每个100k）

package upload;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Arrays;

public class split {
    public static void main(String[] args) {

        int eachSize=100*1024;
        File srcFile =new File("D:/Test/Test.txt");//创建一个文件对象
        splitFile(srcFile,eachSize);
    }

    public static void splitFile(File srcFile,int eachSize){
        //判断文件是否符合拆分要求
        if(srcFile.length()==0){
            throw new RuntimeException("文件不符合拆分要求");
        }
        byte[] fileContent= new byte[(int) srcFile.length()];
        try {
            //将文件内容读取到内存中
            FileInputStream fis=new FileInputStream(srcFile);
            fis.read(fileContent);
            fis.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        //计算要次要拆分为多少份
        int fileNumber;
        if(fileContent.length%eachSize==0){
            fileNumber = fileContent.length/eachSize;
        }else{
            fileNumber = fileContent.length/eachSize+1;
        }

        for(int i=0;i<fileNumber;i++){
            String fileName = srcFile.getName()+"-"+i+".txt";
            File fi = new File(srcFile.getParent(), fileName);//在当前文件路径下创建拆分的文件
            byte[] eachContent;

            //将源文件内容复制到拆分的文件中
            if(i!=fileNumber-1){
                eachContent = Arrays.copyOfRange(fileContent, eachSize*i, eachSize*(i+1));
            }else{
                eachContent = Arrays.copyOfRange(fileContent, eachSize*i, fileContent.length);
            }

            try {
                FileOutputStream fos = new FileOutputStream(fi);
                fos.write(eachContent);
                fos.close();
                System.out.println("输出子文件 "+fi.getAbsoluteFile()+",其大小为"+fi.length()+",每个的大小是"+eachContent.length);
            } catch (Exception e) {
                // TODO: handle exception
                e.printStackTrace();
            }

        }

    }
}

文件合并

package upload;

import java.io.*;
public class compose {
    public static void upload(String destPath,String ... srcPaths){
        if(destPath==null||"".equals(destPath)||srcPaths==null){
            System.out.println("合并失败");
        }
        for (String string : srcPaths) {
            if("".equals(string)||string==null)
                System.out.println("合并失败");
        }
        //合并后的文件名
        String name = srcPaths[0].substring(srcPaths[0].lastIndexOf("\\"));
        String destName = name.substring(0, name.lastIndexOf("-"));
        destPath = destPath+destName;//合并后的文件路径

        File destFile = new File(destPath);//合并后的文件
        OutputStream out = null;
        BufferedOutputStream bos = null;
        try {
            out = new FileOutputStream(destFile);
            bos = new BufferedOutputStream(out);
            for (String src : srcPaths) {
                File srcFile = new File(src);
                InputStream in = new FileInputStream(srcFile);
                BufferedInputStream bis = new BufferedInputStream(in);
                byte[] bytes = new byte[1024*1024];
                int len = -1;
                while((len = bis.read(bytes))!=-1){
                    bos.write(bytes, 0, len);
                }
                bis.close();
                in.close();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            //关闭流
            try {
                if(bos!=null)bos.close();
                if(out!=null)out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
    public static void main(String[] args) {
        String destPath = "D:\\Test";
        //要合并的文件路径
        String[] srcPaths = {
                "D:\\Test\\Test.txt-0.txt",
                "D:\\Test\\Test.txt-1.txt",
                "D:\\Test\\Test.txt-2.txt",
                "D:\\Test\\Test.txt-3.txt",
                "D:\\Test\\Test.txt-4.txt",
                "D:\\Test\\Test.txt-5.txt",
                "D:\\Test\\Test.txt-6.txt",
                "D:\\Test\\Test.txt-7.txt"};
        System.out.println("开始合并。。。");
        upload(destPath, srcPaths);
        System.out.println("合并结束");
    }
}