Java_基础—序列流整合多个

喜欢ヅ旅行 2022-06-11 01:20 125阅读 0赞

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();
        }
    
    }