java将图片转为base64并指定前缀data/image

C 知道回答：可以使用 Java 的 Base64 类将图片转为 base64 编码，然后再添加前缀 data:image。示例代码如下：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Base64;

public class ImageToBase64 {
    public static void main(String[] args) {
        String imagePath = "path/to/image.jpg";
        String base64Prefix = "data:image/jpeg;base64,";
        String base64Image = imageToBase64(imagePath, base64Prefix);
        System.out.println(base64Image);
    }

    public static String imageToBase64(String imagePath, String base64Prefix) {
        String base64Image = "";
        try {
            File file = new File(imagePath);
            FileInputStream imageInFile = new FileInputStream(file);
            byte imageData[] = new byte[(int) file.length()];
            imageInFile.read(imageData);
            base64Image = base64Prefix + Base64.getEncoder().encodeToString(imageData);
            imageInFile.close();
        } catch (IOException e) {
            System.out.println("Error: " + e.getMessage());
        }
        return base64Image;
    }
}