文件切割（FILE SPLIT）

package filesplit;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.util.Scanner;

public class FileSplit {
    public static void main(String[] args) throws IOException {
        FileSplit main = new FileSplit();
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入文件路径：");
        String fileName = scanner.nextLine();
        System.out.print("输入开始百分比（％）：");
        int percent = scanner.nextInt();
        percent = percent > 99 ? 99 : percent;
        int lines = main.count(fileName);
        int startline = (int) (percent * lines / 100);
        System.out.println("文件的总行数是：" + lines);
        System.out.println("文件的开始行号：" + startline);
        main.splitFile(fileName, startline);
        System.out.println("生成完毕！");
    }

    public int count(String fileName) throws IOException {
        InputStream is = new BufferedInputStream(new FileInputStream(fileName));
        byte[] c = new byte[1024];
        int count = 0;
        int readChars = 0;
        while ((readChars = is.read(c)) != -1) {
            for (int i = 0; i < readChars; ++i) {
                if (c[i] == '\n')
                    ++count;
            }
        }
        is.close();
        return count;
    }

    public void splitFile(String fileName, int startline) throws IOException {
        File inFile = new File(fileName);
        BufferedReader in = new BufferedReader(new FileReader(inFile));
        String splitarry[] = inFile.getName().split("\\.");
        String name = splitarry[0];
        String suffix = splitarry.length > 1 ? splitarry[1] : "";
        suffix = suffix != null && suffix.length() > 0 ? "." + suffix : "";
        String outFileName = name + "_" + startline + suffix;

        File outFile = new File(outFileName);
        BufferedWriter out = new BufferedWriter(new FileWriter(outFile));
        String strLine = startline > 0 ? in.readLine() : "";
        int totalLines = 0;
        while (strLine != null) {
            totalLines++;
            if (totalLines >= startline - 1) {
                break;
            }
            strLine = in.readLine();
        }
        // 开始进行输出
        System.out.println("开始输出到文件：" + outFile.getAbsolutePath());
        strLine = in.readLine();
        while (strLine != null) {
            out.write(strLine + '\n');
            strLine = in.readLine();
        }
        in.close();
        out.close();
    }

}

 

----------------------- 运行效果-----------------------

请输入文件路径：F:\mywork\filesplit\test.txt
输入开始百分比（％）：40
文件的总行数是：26
文件的开始行号：10
开始输出到文件：F:\eclipse\workspace\JXWork\test_10.txt
生成完毕！