jdk1.8 Base64Util Illegal base64 character

摘要：用于统一编码格式。由于和内置的遵守的协议不一致，按照照实现的，是按照和两个协议来实现的。由于协议的不同可能导致的解码编码的数据时抛出异常因此需要特别注意保持解码编码的一致性。

最近工作上有个需求，需要根据图片的url下载到本地，并且客户端无法访问到url只能接收base64图片码。因此决定采用jdk自带的Base64进行编码转码存储。

采用了两个工具类：ImageUtil和Base64Util。ImageUtil用于实际操作。Base64Util用于统一编码格式。

由于jdk1.7和jdk1.8内置的Base64遵守的RFC协议不一致，jdk1.7按照照RFC1521实现的，jdk1.8是按照rfc4648和rfc2045两个协议来实现的。具体可以从类注释中查询到。由于协议的不同可能导致jdk1.8的解码jdk1.7编码的数据时抛出java.lang.IllegalArgumentException: Illegal base64 character a异常.因此需要特别注意保持解码编码的一致性。
jdk7的编码结果包含换行；
jdk8的编码结果不包含换行；
jdk8无法解码包含换行的编码结果;

既然得知上述异常产生的由于,故找到解决方案也很简单。

使用apache common包中的org.apache.commons.codec.binary.Base64类进行编码和解码；

编码之后或解码之前去除换行符；

编码和解码使用相同的jdk版本；

ImageUtils

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class ImageUtils {

    /**
     * base64转文件地址
     *
     * @param filePath
     * @param base64
     * @param fileName
     */
    public static void base64ToImg(String filePath, String base64, String fileName) {
        File file = null;
        //创建文件目录
        File dir = new File(filePath);
        if (!dir.exists() && !dir.isDirectory()) {
            dir.mkdirs();
        }
        BufferedOutputStream bos = null;
        java.io.FileOutputStream fos = null;
        try {
            byte[] bytes = Base64Util.decode(base64);
            file = new File(filePath + fileName);
            fos = new java.io.FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * 通过Toolkit获取base64
     *
     * @param url
     * @return
     * @author caoting
     * @date 2018年11月21日
     */
    public static String getBase64ByImgUrl(String url) {
        String suffix = url.substring(url.lastIndexOf(".") + 1);
        try {
            URL urls = new URL(url);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            Image image = Toolkit.getDefaultToolkit().getImage(urls);
            BufferedImage biOut = toBufferedImage(image);
            ImageIO.write(biOut, suffix, baos);
            String base64Str = Base64Util.encode(baos.toByteArray());
            return base64Str;
        } catch (Exception e) {
            return "";
        }

    }

    public static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }
        // This code ensures that all the pixels in the image are loaded
        image = new ImageIcon(image).getImage();
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            int transparency = Transparency.OPAQUE;
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
            // The system does not have a screen
        }
        if (bimage == null) {
            // Create a buffered image using the default color model
            int type = BufferedImage.TYPE_INT_RGB;
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }
        // Copy image to buffered image
        Graphics g = bimage.createGraphics();
        // Paint the image onto the buffered image
        g.drawImage(image, 0, 0, null);
        g.dispose();
        return bimage;
    }

    /**
     * 通过下载二进制流的方式获取base64
     *
     * @param imgUrl 图片url
     * @return 返回图片base64的字符串
     */
    public static String image2Base64(String imgUrl) {

        URL url = null;
        InputStream is = null;
        ByteArrayOutputStream outStream = null;

        HttpURLConnection httpUrl = null;
        try {

            url = new URL(imgUrl);
            httpUrl = (HttpURLConnection) url.openConnection();
            httpUrl.connect();

            httpUrl.getInputStream();
            is = httpUrl.getInputStream();
            outStream = new ByteArrayOutputStream();

            // 创建一个Buffer字符串
            byte[] buffer = new byte[1024];
            // 每次读取的字符串长度，如果为-1，代表全部读取完毕
            int len = 0;
            // 使用一个输入流从buffer里把数据读取出来
            while ((len = is.read(buffer)) != -1) {
                // 用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
                outStream.write(buffer, 0, len);
            }
            // 对字节数组Base64编码
            return Base64Util.encode(outStream.toByteArray());

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outStream != null) {
                try {
                    outStream.close();

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (httpUrl != null) {
                httpUrl.disconnect();
            }
        }
        return imgUrl;
    }
}

Base64Util

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.imageio.stream.FileImageInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Base64Util{
    /**
     * 字符串转图片
     * @param base64Str
     * @return
     */
    public static byte[] decode(String base64Str){
        byte[] b = null;
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            b = decoder.decodeBuffer(replaceEnter(base64Str));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return b;
    }

    /**
     * 图片转字符串
     * @param image
     * @return
     */
    public static String encode(byte[] image){
        BASE64Encoder decoder = new BASE64Encoder();
        return replaceEnter(decoder.encode(image));
    }

    public static String encode(String uri){
        BASE64Encoder encoder = new BASE64Encoder();
        return replaceEnter(encoder.encode(uri.getBytes()));
    }

    /**
     *
     * @path    图片路径
     * @return
     */

    public static byte[] imageTobyte(String path){
        byte[] data = null;
        FileImageInputStream input = null;
        try {
            input = new FileImageInputStream(new File(path));
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            int numBytesRead = 0;
            while((numBytesRead = input.read(buf)) != -1){
                output.write(buf, 0, numBytesRead);
            }
            data = output.toByteArray();
            output.close();
            input.close();

        } catch (Exception e) {
            e.printStackTrace();
        }

        return data;
    }

    public static String replaceEnter(String str){
        String reg ="[
-
]";
        Pattern p = Pattern.compile(reg);
        Matcher m = p.matcher(str);
        return m.replaceAll("");
    }
}