java笔记之IO详解——序列流

序列流，对多个流进行合并。

SequenceInputStream 表示其他输入流的逻辑串联。它从输入流的有序集合开始，并从第一个输入流开始读取，直到到达文件末尾，接着从第二个输入流读取，依次类推，直到到达包含的最后一个输入流的文件末尾为止。

需求：把a.txt与b.txt 文件的内容合并。写入到c.txt。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;

public class test01 {

    public static void main(String[] args) throws IOException  {
        File file01=new File("F:/a.txt");
        File file02=new File("F:/b.txt");
        File out03=new File("F:/c.txt");
        FileInputStream fileInputStream01=new FileInputStream(file01);
        FileInputStream fileInputStream02=new FileInputStream(file02);
        FileOutputStream fileOutputStream =new FileOutputStream(out03);
        ArrayList<FileInputStream> list=new ArrayList<FileInputStream>();//将其添加到Arraylist集合中，
        list.add(fileInputStream01);
        list.add(fileInputStream02);
        int len=0;
        byte buff[]=new byte[1024];
        for (int i = 0; i < list.size(); i++) {
            FileInputStream fileInputStream=list.get(i);//取出对象
            while ((len=fileInputStream.read(buff))!=-1) {//读取内容
                fileOutputStream.write(buff, 0, len);//将字节写出
            }
            fileInputStream.close();
        }
        fileOutputStream.close();  
    }
}

使用SequenceInputStream合并文件。

    public static void merge2() throws IOException{
        //找到目标文件
        File inFile1 = new File("F:\\a.txt");
        File inFile2 = new File("F:\\b.txt");
        File outFile = new File("F:\\c.txt");
        //建立数据的输入输出通道
        FileOutputStream fileOutputStream = new FileOutputStream(outFile);
        
        FileInputStream fileInputStream1 = new FileInputStream(inFile1);
        FileInputStream fileInputStream2 = new FileInputStream(inFile2);
        //建立序列流对象
        SequenceInputStream inputStream = new SequenceInputStream(fileInputStream1,fileInputStream2);
        byte[] buf = new byte[1024];
        int length = 0 ; 
        
        while((length = inputStream.read(buf))!=-1){
            fileOutputStream.write(buf,0,length);
        }
        //关闭资源
        inputStream.close();
        fileOutputStream.close();

    }

此时的SequenceInputStream 只能处理2个，当处理多个时，除了第一种方法，还有我们前面学过的Vector集合，

    public static void combine03() throws IOException{
        File file01=new File("F:/a.txt");
        File file02=new File("F:/b.txt");
        File file03=new File("F:/c.txt");
        File out03=new File("F:/d.txt");
        FileInputStream fileInputStream01=new FileInputStream(file01);
        FileInputStream fileInputStream02=new FileInputStream(file02);
        FileInputStream fileInputStream03=new FileInputStream(file03);
        FileOutputStream fileOutputStream =new FileOutputStream(out03);
        Vector< FileInputStream> vector=new Vector<FileInputStream>();
        vector.add(fileInputStream01);
        vector.add(fileInputStream02);
        vector.add(fileInputStream03);
        Enumeration<FileInputStream> e=vector.elements();
        SequenceInputStream sequenceInputStream = new SequenceInputStream(e);
        
        //读取文件数据
        byte[] buf = new byte[1024];
        int length = 0; 
        
        while((length = sequenceInputStream.read(buf))!=-1){
            fileOutputStream.write(buf,0,length);
        }
        
        //关闭资源
        sequenceInputStream.close();
        fileOutputStream.close();
        
        
    }

 将一个MP3文件进行切割并和并，切割合并不影响播放

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.SequenceInputStream;
import java.util.Enumeration;
import java.util.Vector;

/*
 
 需求： 把一首mp3先切割成n份，然后再把这些文件合并起来。
 
 */


public class Demo2 {

    public static void main(String[] args) throws IOException {
//        cutFile();
        mergeFlile();
    }
    
    //合并
    public static void mergeFlile() throws IOException{
        //找到目标文件
        File dir = new File("F:\\music");
        //通过目标文件夹找到所有的MP3文件，然后把所有的MP3文件添加到vector中。
        Vector<FileInputStream> vector = new Vector<FileInputStream>();
        File[] files = dir.listFiles();
        for(File file : files){
            if(file.getName().endsWith(".mp3")){
                vector.add(new FileInputStream(file));
            }
        }
        //通过Vector获取迭代器
        Enumeration<FileInputStream> e = vector.elements();
        //创建序列流
        SequenceInputStream inputStream = new SequenceInputStream(e);
        //建立文件的输出通道
        FileOutputStream fileOutputStream = new FileOutputStream("F:\\合并.mp3");
        //建立缓冲数组读取文件
        byte[] buf = new byte[1024];
        int length = 0 ; 
        while((length =  inputStream.read(buf))!=-1){
            fileOutputStream.write(buf,0,length);
        }
        //关闭资源
        fileOutputStream.close();
        inputStream.close();
        
    }
    
    
    
    //切割MP3
    public static void cutFile() throws IOException{
        File file = new File("F:\\美女\\1.mp3");
        //目标文件夹
        File dir = new File("F:\\music");
        //建立数据的输入通道
        FileInputStream fileInputStream = new FileInputStream(file);
        //建立缓冲数组读取
        byte[] buf = new byte[1024*1024];
        int length = 0;
        for(int i = 0 ;  (length = fileInputStream.read(buf))!=-1 ; i++){
            FileOutputStream fileOutputStream =    new FileOutputStream(new File(dir,"part"+i+".mp3"));
            fileOutputStream.write(buf,0,length);
            fileOutputStream.close();
        }
        //关闭资源
        fileInputStream.close();
    }
    
    
}