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java如何读取一个txt文件

2026-02-05 11:17:37Java

读取 txt 文件的几种方法

在 Java 中，读取 txt 文件可以通过多种方式实现，以下是常见的几种方法：

使用 `BufferedReader` 逐行读取

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

public class ReadFile {
    public static void main(String[] args) {
        String filePath = "example.txt";
        try (BufferedReader br = new BufferedReader(new FileReader(filePath))) {
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用 `Files.readAllLines` 读取所有行

import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;
import java.io.IOException;

public class ReadFile {
    public static void main(String[] args) {
        String filePath = "example.txt";
        try {
            List<String> lines = Files.readAllLines(Paths.get(filePath));
            for (String line : lines) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用 `Scanner` 逐行读取

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

public class ReadFile {
    public static void main(String[] args) {
        String filePath = "example.txt";
        try (Scanner scanner = new Scanner(new File(filePath))) {
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

使用 `Files.readString` 读取整个文件内容（Java 11+）

import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.IOException;

public class ReadFile {
    public static void main(String[] args) {
        String filePath = "example.txt";
        try {
            String content = Files.readString(Paths.get(filePath));
            System.out.println(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用 `FileInputStream` 读取字节流

import java.io.FileInputStream;
import java.io.IOException;

public class ReadFile {
    public static void main(String[] args) {
        String filePath = "example.txt";
        try (FileInputStream fis = new FileInputStream(filePath)) {
            int content;
            while ((content = fis.read()) != -1) {
                System.out.print((char) content);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}