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();

     }

 }