SequenceInputStream (序列流) ：

可以把多个输入流串联起来读取，先从第一个开始i读取，然后再下一个....

序列流是没有读取文件的能力。

需求：把day01 与 day02的文件合并成一个. -----> 总结.txt

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.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;
 
public class Demo1 {

    
    public static void main(String[] args) throws IOException {
        merge4();
    }
    
    
    public static void merge4() throws IOException{
        //找到目标文件对象
        File inFile1 = new File("F:\\day01.txt");
        File inFile2 = new File("f:\\day02.txt");
        File inFile3 = new File("f:\\day03.txt");
        File outFile = new File("f:\\总结.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);
        FileInputStream fileInputStream3 = new FileInputStream(inFile3);
        
        //
        ArrayList<FileInputStream> list = new ArrayList<FileInputStream>();
        list.add(fileInputStream1);
        list.add(fileInputStream2);
        list.add(fileInputStream3);
        final Iterator<FileInputStream> it = list.iterator();
        
        
        //创建一个序列流对象
        SequenceInputStream inputStream = new SequenceInputStream(new Enumeration<FileInputStream>() {

            @Override
            public boolean hasMoreElements() {
                return it.hasNext();
            }

            @Override
            public FileInputStream nextElement() {
            
                return it.next();
            }
        });
        
        //创建缓冲数组，边读边写
        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();
        
        
    }
    
    //把三个文件合并成一个。
    public static void merge3() throws IOException{
        //找到目标文件对象
        File inFile1 = new File("F:\\day01.txt");
        File inFile2 = new File("f:\\day02.txt");
        File inFile3 = new File("f:\\day03.txt");
        File outFile = new File("f:\\总结.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);
        FileInputStream fileInputStream3 = new FileInputStream(inFile3);
        
        Vector<FileInputStream> v = new Vector<FileInputStream>();   //Vector 是一个线程安全的类，操作效率低。 我想使用ArrayList
        v.add(fileInputStream1);
        v.add(fileInputStream2);
        v.add(fileInputStream3);
        Enumeration<FileInputStream> e = v.elements();  //通过Vector得到一个迭代器。
            
        //创建一个序列流对象
        SequenceInputStream inputStream = new SequenceInputStream(e);
        
        //创建缓冲数组，边读边写
        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();
        
        
    }
    
    
    
    //使用SequenceInputStream完成合并文件的需求
    public static void merge2() throws IOException{
        //找到目标文件对象
        File inFile1 = new File("F:\\day01.txt");
        File inFile2 = new File("f:\\day02.txt");
        File outFile = new File("f:\\总结.txt");
        
        //第二步：建立数据的输入输出通道
        FileOutputStream fileOutputStream = new FileOutputStream(outFile);
        //建立数据的输入输出通道
        FileInputStream fileInputStream1 = new FileInputStream(inFile1);
        FileInputStream fileInputStream2= new FileInputStream(inFile2);
        //创建序列流对象   
        SequenceInputStream sequenceInputStream = new SequenceInputStream(fileInputStream1, fileInputStream2);
        //边读边写
        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();   
    }
    
    
    
    
    
    
    //需求： 合并两个文件到一个文件上。
    public static void merge1() throws IOException{
        //找到目标文件对象
        File inFile1 = new File("F:\\day01.txt");
        File inFile2 = new File("f:\\day02.txt");
        File outFile = new File("f:\\总结.txt");
        //输出流
        FileOutputStream fileOutputStream = new FileOutputStream(outFile);
        //建立数据的输入输出通道
        FileInputStream fileInputStream1 = new FileInputStream(inFile1);
        FileInputStream fileInputStream2= new FileInputStream(inFile2);
        //把输入流对象存储到集合集合中。
        ArrayList<FileInputStream> list = new ArrayList<FileInputStream>();
        list.add(fileInputStream1);
        list.add(fileInputStream2);
        
        //边读边写
        byte[] buf = new byte[1024];
        int length = 0;
        
        for(int i = 0 ; i<list.size() ; i++){
            FileInputStream inputStream = list.get(i);
            while((length = inputStream.read(buf))!=-1){
                fileOutputStream.write(buf,0,length);
            }
            //关闭资源
            inputStream.close();
        }
        fileOutputStream.close();
    }
}