java读取大文件（分割）

如下的程序，将一个行数为fileLines的文本文件平均分为splitNum个小文本文件，其中换行符'r'是linux上的，windows的java换行符是'\r\n'：
package kddcup2012.task2.FileSystem;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;

public class FileSplit
{	
	public static void main(String[] args) throws IOException
	{
		long timer = System.currentTimeMillis();
		int bufferSize = 20 * 1024 * 1024;//设读取文件的缓存为20MB
		
		//建立缓冲文本输入流
		File file = new File("/media/Data/毕业设计/kdd cup/数据/userid_profile.txt");
		FileInputStream fileInputStream = new FileInputStream(file);
		BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);
		InputStreamReader inputStreamReader = new InputStreamReader(bufferedInputStream);
		BufferedReader input = new BufferedReader(inputStreamReader, bufferSize);
		
		int splitNum = 112-1;//要分割的块数减一
		int fileLines = 23669283;//输入文件的行数
		long perSplitLines = fileLines / splitNum;//每个块的行数
		for (int i = 0; i <= splitNum; ++i)
		{
			//分割
			//每个块建立一个输出
			FileWriter output = new FileWriter("/home/haoqiong/part" + i + ".txt");
			String line = null;
			//逐行读取，逐行输出
			for (long lineCounter = 0; lineCounter < perSplitLines && (line = input.readLine()) != null; ++lineCounter)
			{
				output.append(line + "\r");
			}
			output.flush();
			output.close();
			output = null;
		}
		input.close();
		timer = System.currentTimeMillis() - timer;
		System.out.println("处理时间：" + timer);
	}
}

转载地址：http://blog.csdn.net/bhq2010/article/details/7376537