IO流之合并流

SequenceInputStream合并流

可将多个读取流合并，通常用于大文件切割后的合并；

文件的分割

import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.SequenceInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;

public class qiegeAndhebin{

    /**
     * @param args
     * @throws IOException 
     */
    public static void main(String[] args) throws IOException {
//      切割文件
        File dir = new File("hehe");
        if(!dir.exists()){
            dir.mkdir();
        }
        File file = new File("emailcard.bmp");
        FileInputStream fis = new FileInputStream(file);
        FileOutputStream fos = null;
        int len;
        int count = 1;
        byte[] bytes = new byte[2048];
        System.out.println("文件共"+file.length()+"字节，分割成"+file.length()/2048+"个文件");
        while((len = fis.read(bytes)) != -1){  //按照2048字节进行分割文件
            fos = new FileOutputStream(new File(dir,count++ + ".part"));
            fos.write(bytes,0,len);
            fos.flush();
        }
        fos.close();
        fis.close();
        
        

文件的合并

        
//      读取dir目录下所有文件，添加到array集合，
        ArrayList<FileInputStream> array = new ArrayList<FileInputStream>();
        for(int i =0 ; i< dir.listFiles(new hzmFilter("part")).length;i++){
            array.add(new FileInputStream(new File(dir,i+1+".part")));
        }
        Enumeration<FileInputStream> en = Collections.enumeration(array); //枚举
        SequenceInputStream in = new SequenceInputStream(en);//获得合并流，另种传参方式可，直接传入File1，File2,在文件数量及名称已经的情况可用
        FileOutputStream fos1 = new FileOutputStream(new File(dir,"hebin.bmp"));//指定目录创建合并的文件
        int num;
        byte[] bytes1 = new byte[1024];
        while((num = in.read(bytes1)) != -1){
            fos1.write(bytes1,0,num);
            fos1.flush();
        }
        
        fos1.close();
        in.close();
        
    }

}