使用BASE64Decoder完成文件与二进制之间互相转化

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 \* 使用sun.misc.BASE64Decoder和sun.misc.BASE64Encoder
 \* 完成文件转化二进制之间互相转化
 *
 */
public class BASE64test {
  /**
   *
   \* @param path 目标文件
   \* @param path2 生成文件
   */
  public static void encodeBase64File(String path,String path2) throws Exception {
    File file = new File(path);//创建目标文件对象
    FileInputStream inputFile = new FileInputStream(file);//输入流
    FileOutputStream out=new FileOutputStream(path2);//输出流
    OutputStreamWriter osw=new OutputStreamWriter(out);//文字写入流
    //文件读取时未使用缓冲，一次性读取
    byte[] buffer = new byte[(int) file.length()];
    inputFile.read(buffer);
    inputFile.close();
    //new BASE64Encoder().encode(buffer返回String类型的字符串
    //再使用文字输出流将其写出
    osw.write((new BASE64Encoder().encode(buffer)));
    osw.close();
    out.close();
   }
  public static void main(String[] args) {
    String path="C:\\Users\\Public\\Pictures\\Sample Pictures\\EAG42EqA_2560x1600.jpg";
    String path1="C:\\Users\\Public\\Pictures\\Sample Pictures\\EAG42EqA_2560x16002.txt";
    try {
      encodeBase64File(path,path1);
      File file=new File(path1);
      FileInputStream fis=new FileInputStream(file);
      FileOutputStream fos=new FileOutputStream("C:\\Users\\Public\\Pictures\\Sample Pictures\\EAG42EqA_2560x16003.jpg");
      BASE64Decoder bd=new BASE64Decoder();
      byte[] b=bd.decodeBuffer(fis);
      fos.write(b);
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
​    
  }
}

java安装的目录下的jre/lib/rt.jar中有以下两个类实现base64的编码和解码：

sun.misc.BASE64Encoder

sun.misc.BASE64Decoder

下面是java实现：

public class Imagebase64 {
    static BASE64Encoder encoder = new sun.misc.BASE64Encoder();
    static BASE64Decoder decoder = new sun.misc.BASE64Decoder();

    public static void main(String[] args) {
        System.out.println(getImageBinary()); // image to base64
        base64StringToImage(getImageBinary()); // base64 to image
    }

    static String getImageBinary() {
        File f = new File("d://in.jpg");
        try {
            BufferedImage bi = ImageIO.read(f);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            ImageIO.write(bi, "jpg", baos);
            byte[] bytes = baos.toByteArray();

            return encoder.encodeBuffer(bytes).trim();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    static void base64StringToImage(String base64String) {
        try {
            byte[] bytes1 = decoder.decodeBuffer(base64String);
            ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);
            BufferedImage bi1 = ImageIO.read(bais);
            File f1 = new File("d://out.jpg");
            ImageIO.write(bi1, "jpg", f1);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}