Java如何读取文本文件

Java可以使用File类、BufferedReader类和Scanner类等来读取文本文件。

1. 使用File类读取文本文件

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ReadTextFile {
    public static void main(String[] args) {
        try {
            File file = new File("filename.txt");
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
            scanner.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
        }
    }
}

2. 使用BufferedReader类读取文本文件

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ReadTextFile {
    public static void main(String[] args) {
        try {
            BufferedReader reader = new BufferedReader(new FileReader("filename.txt"));
            String line = reader.readLine();
            while (line != null) {
                System.out.println(line);
                line = reader.readLine();
            }
            reader.close();
        } catch (IOException e) {
            System.out.println("Error reading file.");
        }
    }
}

3. 使用Scanner类读取文本文件

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ReadTextFile {
    public static void main(String[] args) {
        try {
            Scanner scanner = new Scanner(new File("filename.txt"));
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
            scanner.close();
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
        }
    }
}