将图片转成base64字符串并在JSP页面显示的Java代码

*本事例主要讲了如下几点: 
 * 1:将图片转换为BASE64加密字符串. 
 * 2:将图片流转换为BASE64加密字符串. 
 * 3:将BASE64加密字符串转换为图片.

* 4:在jsp文件中以引用的方式和BASE64加密字符串方式展示图片.

首先看工具类:

 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;  

 import javax.imageio.ImageIO;  

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

 /**
  * @author IluckySi
  * @since 20150122
  */
 public class ImageUtil {  

     private static BASE64Encoder encoder = new sun.misc.BASE64Encoder();
     private static BASE64Decoder decoder = new sun.misc.BASE64Decoder();  

     /**
      * 将图片转换为BASE64加密字符串.
      * @param imagePath 图片路径.
      * @param format 图片格式.
      * @return
      */
     public String convertImageToByte(String imagePath, String format) {
         File file = new File(imagePath);
         BufferedImage bi = null;
         ByteArrayOutputStream baos = null;
         String result = null;
         try {
             bi = ImageIO.read(file);
             baos = new ByteArrayOutputStream();
             ImageIO.write(bi, format == null ? "jpg" : format, baos);
             byte[] bytes = baos.toByteArray();
             result = encoder.encodeBuffer(bytes).trim();
             System.out.println("将图片转换为BASE64加密字符串成功！");
         } catch (IOException e) {
             System.out.println("将图片转换为 BASE64加密字符串失败: " + e);
         } finally {
             try {
                 if(baos != null) {
                     baos.close();
                     baos = null;
                 }
             } catch (Exception e) {
                 System.out.println("关闭文件流发生异常: " + e);
             }
         }
         return result;
     }  

     /**
      * 将图片流转换为BASE64加密字符串.
      * @param imageInputStream
      * @param format 图片格式.
      * @return
      */
     public String convertImageStreamToByte(InputStream imageInputStream, String format) {
         BufferedImage bi = null;
         ByteArrayOutputStream baos = null;
         String result = null;
         try {
             bi = ImageIO.read(imageInputStream);
             baos = new ByteArrayOutputStream();
             ImageIO.write(bi, format == null ? "jpg" : format, baos);
             byte[] bytes = baos.toByteArray();
             result = encoder.encodeBuffer(bytes).trim();
             System.out.println("将图片流转换为BASE64加密字符串成功！");
         } catch (IOException e) {
             System.out.println("将图片流转换为 BASE64加密字符串失败: " + e);
         } finally {
             try {
                 if(baos != null) {
                     baos.close();
                     baos = null;
                 }
             } catch (Exception e) {
                 System.out.println("关闭文件流发生异常: " + e);
             }
         }
         return result;
     }  

     /**
      * 将BASE64加密字符串转换为图片.
      * @param base64String
      * @param imagePath 图片生成路径.
      * @param format 图片格式.
      */
     public void convertByteToImage(String base64String, String imagePath, String format) {
         byte[] bytes = null;
         ByteArrayInputStream bais = null;
         BufferedImage bi = null;
         File file = null;
         try {
             bytes = decoder.decodeBuffer(base64String);
             bais = new ByteArrayInputStream(bytes);
             bi = ImageIO.read(bais);
             file = new File(imagePath);
             ImageIO.write(bi, format == null ? "jpg" : format, file);
             System.out.println("将BASE64加密字符串转换为图片成功！");
         } catch (IOException e) {
             System.out.println("将BASE64加密字符串转换为图片失败: " + e);
         } finally {
             try {
                 if(bais != null) {
                     bais.close();
                     bais = null;
                 }
             } catch (Exception e) {
                 System.out.println("关闭文件流发生异常: " + e);
             }
         }
     }
 }

然后看测试类：

 import java.io.InputStream;  

 import com.ilucky.util.image.ImageUtil;  

 /**
  * 本事例主要讲了如下几点:
  * 1:将图片转换为BASE64加密字符串.
  * 2:将图片流转换为BASE64加密字符串.
  * 3:将BASE64加密字符串转换为图片.
  * 4:在jsp文件中以引用的方式和BASE64加密字符串方式展示图片.
  * @author IluckySi
  * @since 20150122
  */
 public class MainTest {  

     public static void main(String[] args) {
         ImageUtil imageUtil = new ImageUtil();  

         String base64String = imageUtil.convertImageToByte("D:\\test.png", "png");
         System.out.println(base64String);
         imageUtil.convertByteToImage(base64String, "D:\\test2.png", "png");  

         InputStream is = MainTest.class.getResourceAsStream("test.png");
         String base64String2 = imageUtil.convertImageStreamToByte(is, "png");
         System.out.println(base64String2);
         imageUtil.convertByteToImage(base64String2, "D:\\test3.png", "png");
     }
 }

最后看jsp文件:

 <!DOCTYPE html>
 <html>
   <head>
     <title>index.html</title>
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="this is my page">
     <meta http-equiv="content-type" content="text/html; charset=UTF-8">
   </head>
   <body>
     <!--
     data表示取得数据的协定名称,image/png是数据类型名称,base64 是数据的编码方法,
     逗号后面是image/png文件base64编码后的数据.
     data:text/css;base64,base64编码的CSS代码
     data:text/javascript,Javascript代码
     data:text/javascript;base64,base64编码的Javascript代码
     data:image/gif;base64,base64编码的gif图片数据
     data:image/png;base64,base64编码的png图片数据
     data:image/jpeg;base64,base64编码的jpeg图片数据
     data:image/x-icon;base64,base64编码的icon图片数据
      -->
     <img src="test.png"/>
     <img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAFYklEQVR42sVXfUyUdRz/8XKhMZQO
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   </body>
 </html>