JAVA小练习150——序列流

墨蓝 2021-11-22 03:14 188阅读 0赞

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;
    
    /*
    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。
    
     */
    public class Demo150 {
    
    	
    	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();
    	}