大文件的写入与分割

//大文件的写入
public class LargeMappedFiles extends File{

	public LargeMappedFiles(String pathname) {
		super(pathname);
		// TODO Auto-generated constructor stub
	}
  //写入大数据文件
	public void writeData(String pathName,long num) throws IOException{
		pathName=pathName+"\\bigdata.txt";
		FileWriter fWriter=new FileWriter(pathName);
		BufferedWriter bWriter=new BufferedWriter(fWriter);
		for (int i = 0; i < num; i++) {
			bWriter.write(new Random().nextInt(Integer.MAX_VALUE)+"\r\n");
		}
		bWriter.close();
	}
 //分割大数据文件
//分割大数据文件
	public void dividFile(String pathName,String divideName,int count) throws IOException{
		pathName=pathName+"\\bigdata.txt";
		FileWriter fileWriter=null;
		BufferedWriter bufferedWriter=null;
		FileReader fileReader=new FileReader(pathName);
		BufferedReader bufferedReader=new BufferedReader(fileReader);
		LinkedList writeList=new LinkedList();
		LinkedList bwlist=new LinkedList();
		int j=0;
		for (int i = 0; i < count; i++) {
			fileWriter=new FileWriter(divideName+"\\"+i+".txt",false);
			bufferedWriter=new BufferedWriter(fileWriter);
			writeList.add(fileWriter);
			bwlist.add(bufferedWriter);
		}
		while(bufferedReader.ready()){
			int num=1;
			for (Iterator iterator = bwlist.iterator(); iterator.hasNext();) {
				BufferedWriter type = (BufferedWriter) iterator.next();  
				if(j==num)//判断轮到第几个文件流写入数据了  
		        {  
		         //写入数据，跳出，进行下一个文件流，下一个数据的写入  
		         type.write(bufferedReader.readLine() + "\r\n");  
		         break;  
		        }  
		        num++;  
			}
			//判断是否到了最后一个文件流了  
		       if (j >= count) {  
		        j = 1;  
		       } else  
		        j++;  
		}
		bufferedReader.close();  
		fileReader.close();
		 for (Iterator iterator = bwlist.iterator(); iterator.hasNext();) {  
		       BufferedWriter object = (BufferedWriter) iterator.next();  
		       object.close();  
		      }  
		      //遍历关闭所有子文件流  
		      for (Iterator iterator = writeList.iterator(); iterator.hasNext();) {  
		       FileWriter object = (FileWriter) iterator.next();  
		       object.close();  
		      }  
	}
}
public class Test {

	/**
	 * @param args
	 * 
	 *
	 */
	public static void main(String[] args) {

       
          //小提醒：系统只能自动创建文件不能创建文件夹
        //大数据文件
		String pathName="D:\\123";
		LargeMappedFiles lmf=new LargeMappedFiles(pathName);
		//存入大数据
		try {
			/*
			 * 此处也可以改为
			 * lmf.writeData(pathName, 10000000);
			 */
			lmf.writeData(pathName, 1000000000000000000000L);
		} catch (IOException e) {
			e.printStackTrace();
		}
		//切割文件
		String divideName = "D:"+"\\123";  
		lmf.dividFile(pathName, divideName,4);
	}
}