我尝试使用读取文件功能，但它不起作用

try:
    with open('filename.txt', 'r') as file:
        content = file.read()
        print(content)
except FileNotFoundError:
    print("文件未找到")
except IOError:
    print("读取文件时发生错误")

import java.nio.file.*;
import java.io.IOException;

public class FileReaderExample {
    public static void main(String[] args) {
        Path path = Paths.get("filename.txt");
        try {
            byte[] bytes = Files.readAllBytes(path);
            String content = new String(bytes, StandardCharsets.UTF_8);
            System.out.println(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

const fs = require('fs');

fs.readFile('filename.txt', 'utf8', (err, data) => {
    if (err) {
        console.error(err);
        return;
    }
    console.log(data);
});

<input type="file" id="fileInput">
<script>
    document.getElementById('fileInput').addEventListener('change', function(event) {
        const file = event.target.files[0];
        const reader = new FileReader();
        reader.onload = function(e) {
            console.log(e.target.result);
        };
        reader.readAsText(file);
    });
</script>