Java中图片转换为Base64的示例及注意事项

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

public class ImageToBase64Converter {
    
    public static void main(String[] args) {
        // 指定要转换的图片路径
        String imagePath = "path/to/your/image.jpg"; // 替换为实际图片路径
        
        try {
            String base64String = convertImageToBase64(imagePath);
            System.out.println("Base64 String: " + base64String);
        } catch (IOException e) {
            System.err.println("Error converting image to Base64: " + e.getMessage());
        }
    }

    /**
     * 将给定路径的图像转换为 Base64 编码字符串
     *
     * @param imagePath 图像文件的路径
     * @return Base64 编码的字符串
     * @throws IOException 如果读取文件时发生错误
     */
    public static String convertImageToBase64(String imagePath) throws IOException {
        File imageFile = new File(imagePath);
        byte[] fileContent = new byte[(int) imageFile.length()];

        try (FileInputStream fileInputStream = new FileInputStream(imageFile)) {
            fileInputStream.read(fileContent);
        }

        return Base64.getEncoder().encodeToString(fileContent);
    }
}

package cn.com;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class Base64Test 
{
    public static void main(String[] args)
    {
        String strImg = GetImageStr();
        System.out.println(strImg);
        GenerateImage(strImg);
    }
    //图片转化成base64字符串
    public static String GetImageStr()
    {//将图片文件转化为字节数组字符串，并对其进行Base64编码处理
        String imgFile = "d://test.jpg";//待处理的图片
        InputStream in = null;
        byte[] data = null;
        //读取图片字节数组
        try 
        {
            in = new FileInputStream(imgFile);        
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }
        //对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);//返回Base64编码过的字节数组字符串
    }
    //base64字符串转化成图片
    public static boolean GenerateImage(String imgStr)
    {   //对字节数组字符串进行Base64解码并生成图片
        if (imgStr == null) //图像数据为空
            return false;
        BASE64Decoder decoder = new BASE64Decoder();
        try 
        {
            //Base64解码
            byte[] b = decoder.decodeBuffer(imgStr);
            for(int i=0;i<b.length;++i)
            {
                if(b[i]<0)
                {//调整异常数据
                    b[i]+=256;
                }
            }
            //生成jpeg图片
            String imgFilePath = "d://222.jpg";//新生成的图片
            OutputStream out = new FileOutputStream(imgFilePath);    
            out.write(b);
            out.flush();
            out.close();
            return true;
        } 
        catch (Exception e) 
        {
            return false;
        }
    }
}