IO流_SequenceInputStream(序列流)

SequenceInputStream(序列流):就是将多个流合成一个有序的流

需求：将三个文件中的数据合并到一个文件中

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

public class SequenceInputStreamDemo {
    public static void main(String[] args) throws IOException {
        
        //该集合效率低，所以用ArrayList集合，但是该集合没有枚举，所以要自定义一个枚举
        Vector<FileInputStream> v = new Vector<FileInputStream>();
        
        v.add(new FileInputStream("F:\0.txt"));
        v.add(new FileInputStream("F:\a.txt"));
        v.add(new FileInputStream("F:\info.txt"));
        
        Enumeration<FileInputStream> en = v.elements();
        
        SequenceInputStream sis = new SequenceInputStream(en);
        
        FileOutputStream fos = new FileOutputStream("F:\feng.txt");
        
        byte[] buf = new byte[1024];
        int len = 0;
        while((len=sis.read(buf))!=-1){
            fos.write(buf,0,len);
        }
        
        sis.close();
        fos.close();
    }

}

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;
import java.util.Iterator;

public class SequenceInputStreamDemo {
    public static void main(String[] args) throws IOException {
        ArrayList<FileInputStream> al = new ArrayList<FileInputStream>();
        al.add(new FileInputStream("F:\0.txt"));
        al.add(new FileInputStream("F:\a.txt"));
        al.add(new FileInputStream("F:\info.txt"));
        
        Enumeration<FileInputStream> en = Collections.enumeration(al);//该方法的原理就是下面自定义的枚举
        /*
        
        final Iterator<FileInputStream> it = al.iterator();
        //自定义枚举，与ArrayList的迭代器结合使用
        Enumeration<FileInputStream> en = new Enumeration<FileInputStream>() {
            @Override
            public boolean hasMoreElements() {
                return it.hasNext();
            }
            @Override
            public FileInputStream nextElement() {
                return it.next();
            }
        };
        */
        
        SequenceInputStream sis = new SequenceInputStream(en);
        
        FileOutputStream fos = new FileOutputStream("F:\jian.txt");
        
        byte[] buf = new byte[1024];
        int len = 0;
        while((len=sis.read(buf))!=-1){
            fos.write(buf,0,len);
        }
        
        sis.close();
        fos.close();
            
    }

}