Java 文件写入字符：FileWriter 和 BufferedWriter 实例教程

Java可以使用FileWriter类或者BufferedWriter类来写入字符到文件中。

使用FileWriter类：

import java.io.FileWriter;
import java.io.IOException;

public class WriteToFileExample {

    public static void main(String[] args) {
        try {
            FileWriter myWriter = new FileWriter('filename.txt');
            myWriter.write('Hello World!');
            myWriter.close();
            System.out.println('Successfully wrote to the file.');
        } catch (IOException e) {
            System.out.println('An error occurred.');
            e.printStackTrace();
        }
    }
}

使用BufferedWriter类：

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class WriteToFileExample {

    public static void main(String[] args) {
        try {
            BufferedWriter myWriter = new BufferedWriter(new FileWriter('filename.txt'));
            myWriter.write('Hello World!');
            myWriter.close();
            System.out.println('Successfully wrote to the file.');
        } catch (IOException e) {
            System.out.println('An error occurred.');
            e.printStackTrace();
        }
    }
}

需要注意的是，在写入字符时，需要在字符串后面加上换行符\n，否则所有字符都会被写在同一行中。