Java_基础—序列流整合多个

package com.soar.otherio;

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;

public class Demo1_SequenceInputStream {
/*
* * * 1.什么是序列流
 * 序列流可以把多个字节输入流整合成一个, 从序列流中读取数据时, 将从被整合的第一个流开始读, 读完一个之后继续读第二个, 以此类推.
* * * 2.使用方式
 * 整合两个: SequenceInputStream(InputStream, InputStream)
 * 整合多个: SequenceInputStream(Enumeration)
 */
public static void main(String[] args) throws IOException {
//demo1();
//demo2();
        FileInputStream fis1 = new FileInputStream("a.txt");
        FileInputStream fis2 = new FileInputStream("b.txt");
        FileInputStream fis3 = new FileInputStream("c.txt");

        Vector<FileInputStream> v = new Vector<>();     //创建集合对象
        v.add(fis1);                                    //将流对象存储进来
        v.add(fis2);
        v.add(fis3);

        Enumeration<FileInputStream> en = v.elements();
        SequenceInputStream sis = new SequenceInputStream(en);  //将枚举中的输入流整合成一个
        FileOutputStream fos = new FileOutputStream("d.txt");

int b;
while((b = sis.read()) != -1){
            fos.write(b);
        }
        sis.close();
        fos.close();
    }

private static void demo2() throws FileNotFoundException, IOException {
        FileInputStream fis1 = new FileInputStream("a.txt");
        FileInputStream fis2 = new FileInputStream("b.txt");
        SequenceInputStream sis = new SequenceInputStream(fis1, fis2);
        FileOutputStream fos = new FileOutputStream("c.txt");

int b;
while((b = sis.read()) != -1){
            fos.write(b);
        }
        sis.close();            //sis在关闭的时候，会将构造方法中传入的流对象也都关闭
        fos.close();
    }

private static void demo1() throws FileNotFoundException, IOException {
        FileInputStream fis1 = new FileInputStream("a.txt");    //创建字节输入流关联a.txt
        FileOutputStream fos = new FileOutputStream("c.txt");   //创建字节输出流关联c.txt

int b1;
while((b1 = fis1.read()) != -1){        //不断地在a.txt上读取字节
            fos.write(b1);                      //将独到的字节写道c.txt
        }
        fis1.close();                           //关闭字节流

        FileInputStream fis2 = new FileInputStream("b.txt");

int b2;
while((b2 = fis2.read()) != -1){
            fos.write(b2);
        }
        fis2.close();
        fos.close();
    }

}