[置顶] 使用 IO 流，分割/合并 处理大文件

import java.io.*;
import java.util.*;
class SplitFileDemo
{
	public static void main (String[] args) throws IOException
	{
		splitFile();
		merge();
	}
	
	/*
		合并文件
	*/
	public static void merge() throws IOException
	{
		ArrayList<FileInputStream> al = new ArrayList<FileInputStream>();
		/*
		按 1024 分割文件为 2 个子文件，实际按文件大小而定，也可以使用 File 对象来动态
		的获得该路径下所有 .part 文件的数量
		*/
		for(int x = 1; x<=2; x++)
		{
			al.add(new FileInputStream(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("sss.jpg");
		
		byte[] buf = new byte[1024*1024];
		int len = 0;
		while((len=sis.read(buf))!=-1)
		{
			fos.write(buf,0,len);
		}
		fos.close();
		sis.close();
	}
	
	/*
		切割文件
	*/
	public static void splitFile() throws IOException
	{
		FileInputStream fis = new FileInputStream("lcts.jpg");//图片
		
		FileOutputStream fos = null;
		
		byte[] buf = new byte[1024*1024];
		
		int len = 0;
		
		int count = 1;
		
		while((len = fis.read(buf))!=-1)
		{
			fos = new FileOutputStream((count++)+".part");
			fos.write(buf,0,len);
			fos.close();
		}
		fis.close();
	}
}