用IO流删除文件中指定行数的内容

Question

怎么用IO流删除指定行数的内容啊，真的很着急，麻烦彭于晏，吴彦祖回答一下

Answer 1

import java.io.*;

public class DeleteLineDemo {
    public static void deleteLines(String filePath, int[] lineNumbers) throws IOException {
        File oldFile = new File(filePath);
        File newFile = new File(filePath + ".tmp"); // 新建临时文件
        BufferedReader reader = new BufferedReader(new FileReader(oldFile));
        BufferedWriter writer = new BufferedWriter(new FileWriter(newFile));
        String line;
        int lineNumber = 0;
        while ((line = reader.readLine()) != null) {
            lineNumber++;
            if (!contains(lineNumbers, lineNumber)) { // 判断当前行是否需要保留
                writer.write(line);
                writer.newLine();
            }
        }
        reader.close();
        writer.close();
        oldFile.delete(); // 删除旧文件
        newFile.renameTo(oldFile); // 重命名临时文件为原文件名
    }

    private static boolean contains(int[] arr, int target) {
        for (int num : arr) {
            if (num == target) {
                return true;
            }
        }
        return false;
    }

    public static void main(String[] args) throws IOException {
        String filePath = "test.txt";
        int[] lineNumbers = {2, 4}; // 需要删除的行号
        deleteLines(filePath, lineNumbers);
    }
}