Java读写一个包含字母数字的txt文件的正确编码方式及代码

针对包含字母数字的txt文件，一般情况下使用UTF-8编码即可。

以下是Java读取和写入txt文件的代码示例：

读取txt文件：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class ReadTxt {
    public static void main(String[] args) {
        String filePath = "test.txt"; // 文件路径
        File file = new File(filePath);
        try {
            FileInputStream fileInputStream = new FileInputStream(file);
            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
            }
            bufferedReader.close();
            inputStreamReader.close();
            fileInputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

写入txt文件：

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class WriteTxt {
    public static void main(String[] args) {
        String filePath = "test.txt"; // 文件路径
        File file = new File(filePath);
        try {
            FileOutputStream fileOutputStream = new FileOutputStream(file);
            OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, "UTF-8");
            BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter);
            bufferedWriter.write("Hello, world!");
            bufferedWriter.newLine(); // 换行
            bufferedWriter.write("你好，世界！");
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStreamWriter.close();
            fileOutputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

需要注意的是，以上代码中的文件路径需要根据实际情况进行修改。