java——文件合并

文件合并的原理和使用SequenceInputStream，实现文件碎片的合并

package com.zhaoqian.transstream;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

public class Demo7 {

    public static void main(String[] args) throws Exception {
        //文件合并
//      File file = new File("F:"+File.separator+"PartFiles"+File.separator+"my.properties");
//      FileInputStream fsinfo = new FileInputStream(file);
        
        
//      MergerFile_1();
        MergerFile_2();
    }

    public static void MergerFile_2() throws Exception {
        File path = new File("F:"+File.separator+"PartFiles");
        
        // 创建集合
        List<FileInputStream> list = new ArrayList<FileInputStream>();
        
        for (int i = 1; i < 7; i++) {
            // 保存所有的输入流
            list.add(new FileInputStream(new File(path,i+".part")));
        }
        
        // 通过流工具类，获取一个枚举对象
        Enumeration<FileInputStream> en = Collections.enumeration(list);
        
        // 源
        SequenceInputStream sis = new SequenceInputStream(en);
        
        // 写入目的文件
        FileOutputStream fos = new FileOutputStream(new File(path,"1.mp3"));
        
        byte[] by = new byte[1024];
        int len = 0;
        while((len = sis.read(by))!=-1){
            fos.write(by, 0, len);
        }
        
        fos.close();
        sis.close();
        
    }

    public static void MergerFile_1() throws Exception {
        List<FileInputStream> list = new ArrayList<FileInputStream>();
        
        // 获取读取流对象
        for (int i = 1; i < 7; i++) {
            list.add(new FileInputStream("F:"+File.separator+"PartFiles"+File.separator+i+".part"));
        }
        
        FileOutputStream fos = new FileOutputStream(new File("F:"+File.separator+"PartFiles"+File.separator+"0.mp3"));
        
        byte[] buf = new byte[1024*1024];
        
        // 遍历集合，获取流对象
        for (FileInputStream fis : list) {
            int len = 0;
            while((len = fis.read(buf)) != -1){
                fos.write(buf, 0, len);
            }
            fis.close();
        }
        
        fos.close();
        
    }

}