[Statistics of how many lines of Java code there are in the xx directory]

chance

In the interview yesterday, I was asked how many lines of code have I written? I don't know how to answer for a while, and I don't have a concept, because I have never counted the number of lines of code!
After the interview, I thought about counting

---

accomplish

.javaIn fact, it is not difficult to implement. We only need to sum the number of lines of all files ending in the specified directory . Here, depth-first traversal is used for statistics. The code is as follows:

import java.io.*;
import java.util.Scanner;

/**
 * @program: leetCode
 * @description: 求某个目录下的java代码有多少行
 * @author: liangjiayy
 * @create: 2022-09-29 21:40
 **/
public class SumOfCodeLineCount {
    
    
    /**
     * 要统计的文件的后缀名
     */
    private static final String SUFFIX = ".java";

    public static void main(String[] args) {
    
    
        //定义起始目录
        String dir = "C:\\Users\\AikeTech\\IdeaProjects\\";

        System.out.println("你要统计的起始目录是：\"" + dir + "\"，确定请输入\"Y\":");
        String input = new Scanner(System.in).nextLine();
        if (!"y".equalsIgnoreCase(input.trim())) {
    
    
            System.out.println("你已取消统计！");
            return;
        }

        //获取该目录下所有java代码的行数
        long lineCount = getLineCount(dir);
        System.out.println("\"" + dir + "\"目录下，后缀为\"" + SUFFIX + "\"的代码共有 " + lineCount + " 行！");
    }

    /**
     * 获取某个目录下，所有后缀名为 SUFFIX（类变量）  的文件的行数
     *
     * @param dir
     * @return
     */
    private static long getLineCount(String dir) {
    
    
        File file = new File(dir);

        if (!file.isDirectory()) {
    
    
            //是个文件，统计有多少行
            if (dir.endsWith(SUFFIX)) {
    
    
                return statisticalLineCount(file);
            }
            return 0;
        }

        //是个目录，递归
        String[] list = file.list();
        if (list == null) {
    
    
            return 0;
        }

        long sum = 0;
        for (String l : list) {
    
    
            //父目录 + 分隔符 + 文件/目录名
            sum += getLineCount(dir + "\\" + l);
        }

        return sum;
    }

    /**
     * 统计某个文件的行树
     *
     * @param file
     * @return
     */
    private static long statisticalLineCount(File file) {
    
    
        try (LineNumberReader lineNumberReader = new LineNumberReader(new FileReader(file))) {
    
    
            long length = file.length();
            lineNumberReader.skip(length);
            return lineNumberReader.getLineNumber();
        } catch (FileNotFoundException fileNotFoundException) {
    
    
            fileNotFoundException.printStackTrace();
        } catch (IOException e) {
    
    
            e.printStackTrace();
        }
        return 0;
    }
}

operation result:

use

How to use the above class?

• If you also want to count the number of lines of all java codes in a certain directory, just modify dir in the above code: it will find the number of lines of all files ending with .java in this directory
  

• If you count the number of lines in other files, you also need to modify the following variables (suffix name)