JAVA IO流相关代码（打印流 和 文件拼接）

Posted 2022-02-06 小乖乖的臭坏坏

打印流：

该流提供了打印方法，可以将各种数据类型的数据都原样打印。

字节打印流：
PrintStream
构造函数可以接收的参数类型：
1，file对象。File
2，字符串路径。String
3，字节输出流。OutputStream

字符打印流：
PrintWriter
构造函数可以接收的参数类型：
1，file对象。File
2，字符串路径。String
3，字节输出流。OutputStream
4，字符输出流，Writer。

打印流示例代码1

import java.io.*;

class  PrintStreamDemo

	public static void main(String[] args) throws IOException
	
		BufferedReader bufr = 
			new BufferedReader(new InputStreamReader(System.in));

		PrintWriter out = new PrintWriter(new FileWriter("a.txt"),true);

		String line = null;

		while((line=bufr.readLine())!=null)
		
			if("over".equals(line))
				break;
			out.println(line.toUpperCase());
			//out.flush();
		

		out.close();
		bufr.close();

		

打印流示例代码2

import java.io.*;
import java.util.*;
class SequenceDemo 

	public static void main(String[] args) throws IOException
	
		Vector<FileInputStream> v = new Vector<FileInputStream>();

		v.add(new FileInputStream("c:\\\\1.txt"));
		v.add(new FileInputStream("c:\\\\2.txt"));
		v.add(new FileInputStream("c:\\\\3.txt"));

		Enumeration<FileInputStream> en = v.elements();

		SequenceInputStream sis = new SequenceInputStream(en);

		FileOutputStream fos = new FileOutputStream("c:\\\\4.txt");

		byte[] buf = new byte[1024];

		int len =0;
		while((len=sis.read(buf))!=-1)
		
			fos.write(buf,0,len);
		

		fos.close();
		sis.close();
	

文件拼接示例代码

import java.io.*;
import java.util.*;

class SplitFile 

	public static void main(String[] args) throws IOException
	
		//splitFile();
		merge();
	


	public static void merge()throws IOException
	
		ArrayList<FileInputStream> al = new ArrayList<FileInputStream>();

		for(int x=1; x<=3; x++)
		
			al.add(new FileInputStream("c:\\\\splitfiles\\\\"+x+".part"));
		

		final Iterator<FileInputStream> it = al.iterator();

		Enumeration<FileInputStream> en = new Enumeration<FileInputStream>()
		
			public boolean hasMoreElements()
			
				return it.hasNext();
			
			public FileInputStream nextElement()
			
				return it.next();
			
		;

		SequenceInputStream sis = new SequenceInputStream(en);


		FileOutputStream fos = new FileOutputStream("c:\\\\splitfiles\\\\0.bmp");

		byte[] buf = new byte[1024];

		int len = 0;

		while((len=sis.read(buf))!=-1)
		
			fos.write(buf,0,len);
		

		fos.close();
		sis.close();
	

	public static void splitFile()throws IOException
	
		FileInputStream fis =  new FileInputStream("c:\\\\1.bmp");

		FileOutputStream fos = null;


		byte[] buf = new byte[1024*1024];

		int len = 0;
		int count = 1;
		while((len=fis.read(buf))!=-1)
		
			fos = new FileOutputStream("c:\\\\splitfiles\\\\"+(count++)+".part");
			fos.write(buf,0,len);
			fos.close();
		
		
		fis.close();
		
	

参考：
毕向东