阅读所有文件,更改内容,再次保存

with open("file.txt", "r") as f:
    content = f.read()

new_content = content.replace("old_text", "new_text")

with open("file.txt", "w") as f:
    f.write(new_content)

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.BufferedReader;
import java.io.BufferedWriter;

public class FileModifier {
    public static void main(String[] args) {
        try {
            File file = new File("file.txt");
            BufferedReader reader = new BufferedReader(new FileReader(file));
            StringBuilder stringBuilder = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                stringBuilder.append(line).append("\n");
            }
            reader.close();
            String content = stringBuilder.toString();
            String newContent = content.replace("old_text", "new_text");
            BufferedWriter writer = new BufferedWriter(new FileWriter(file));
            writer.write(newContent);
            writer.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

const fs = require("fs");

fs.readFile("file.txt", "utf8", (err, content) => {
    if (err) {
        console.error(err);
        return;
    }
    const newContent = content.replace("old_text", "new_text");
    fs.writeFile("file.txt", newContent, (err) => {
        if (err) {
            console.error(err);
            return;
        }
    });
});