큰 파일 을 작은 파일 로 분해 자바

package zx.tools;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class FileSpiliter {

	/**
	 *       
	 * @param rows          
	 * @param sourceFilePath        
	 * @param targetDirectoryPath             
	 */
	public static void splitDataToSaveFile(int rows, String sourceFilePath,
			String targetDirectoryPath) {
		long start1 = System.currentTimeMillis();

		File sourceFile = new File(sourceFilePath);
		File targetFile = new File(targetDirectoryPath);
		if (!sourceFile.exists() || rows <= 0 || sourceFile.isDirectory()) {
			return;
		}
		if (targetFile.exists()) {
			if (!targetFile.isDirectory()) {
				return;
			}
		} else {
			targetFile.mkdirs();
		}
		try {

			InputStreamReader in = new InputStreamReader(new FileInputStream(sourceFilePath),"UTF-8");
			BufferedReader br=new BufferedReader(in);

			BufferedWriter bw = null;
			StringBuilder str = new StringBuilder();
			String tempData = br.readLine();
			int i = 1, s = 0;
			long start2 = System.currentTimeMillis();
			while (tempData != null) {
				str.append(tempData + "\r
");
				if (i % rows == 0) {
					bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream( 
							targetFile.getAbsolutePath() + "/" +  sourceFile.getName() +"_" + (s+1) +".log"), "UTF-8"),1024); 

					bw.write(str.toString());
					bw.close();

					str = new StringBuilder();
					start2 = System.currentTimeMillis();
					s += 1;
				}
				i++;
				tempData = br.readLine();
			}
			if ((i - 1) % rows != 0) {

				bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream( 
						targetFile.getAbsolutePath() + "/" +  sourceFile.getName() +"_" + (s+1) +".log"), "UTF-8"),1024); 
				bw.write(str.toString());
				bw.close();
				br.close();

				s += 1;
			}
			in.close();

		} catch (Exception e) {
		}
	}

	public static void main(String[] args) {
		FileSpiliter.splitDataToSaveFile(100000, "D:/log/out.log-20180927_10.33.100.168", "D:/log/out.log-20180927/");
	}


}