*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:

  1 import java.awt.image.BufferedImage;  
  2 import java.io.ByteArrayInputStream;  
  3 import java.io.ByteArrayOutputStream;  
  4 import java.io.File;  
  5 import java.io.IOException;  
  6 import java.io.InputStream;  
  8 import javax.imageio.ImageIO;  
 10 import sun.misc.BASE64Decoder;  
 11 import sun.misc.BASE64Encoder;  
 13 /** 
 14  * @author IluckySi 
 15  * @since 20150122 
 16  */ 
 17 public class ImageUtil {  
 19     private static BASE64Encoder encoder = new sun.misc.BASE64Encoder();  
 20     private static BASE64Decoder decoder = new sun.misc.BASE64Decoder();  
 22     /** 
 23      * 将图片转换为BASE64加密字符串. 
 24      * @param imagePath 图片路径. 
 25      * @param format 图片格式. 
 26      * @return 
 27      */ 
 28     public String convertImageToByte(String imagePath, String format) {  
 29         File file = new File(imagePath);  
 30         BufferedImage bi = null;  
 31         ByteArrayOutputStream baos = null;  
 32         String result = null;  
 33         try {  
 34             bi = ImageIO.read(file);  
 35             baos = new ByteArrayOutputStream();  
 36             ImageIO.write(bi, format == null ? "jpg" : format, baos);  
 37             byte[] bytes = baos.toByteArray();  
 38             result = encoder.encodeBuffer(bytes).trim();  
 39             System.out.println("将图片转换为BASE64加密字符串成功！");  
 40         } catch (IOException e) {  
 41             System.out.println("将图片转换为 BASE64加密字符串失败: " + e);  
 42         } finally {  
 43             try {  
 44                 if(baos != null) {  
 45                     baos.close();  
 46                     baos = null;  
 47                 }  
 48             } catch (Exception e) {  
 49                 System.out.println("关闭文件流发生异常: " + e);  
 50             }  
 51         }  
 52         return result;  
 53     }  
 55     /** 
 56      * 将图片流转换为BASE64加密字符串. 
 57      * @param imageInputStream 
 58      * @param format 图片格式. 
 59      * @return 
 60      */ 
 61     public String convertImageStreamToByte(InputStream imageInputStream, String format) {  
 62         BufferedImage bi = null;  
 63         ByteArrayOutputStream baos = null;  
 64         String result = null;  
 65         try {  
 66             bi = ImageIO.read(imageInputStream);  
 67             baos = new ByteArrayOutputStream();  
 68             ImageIO.write(bi, format == null ? "jpg" : format, baos);  
 69             byte[] bytes = baos.toByteArray();  
 70             result = encoder.encodeBuffer(bytes).trim();  
 71             System.out.println("将图片流转换为BASE64加密字符串成功！");  
 72         } catch (IOException e) {  
 73             System.out.println("将图片流转换为 BASE64加密字符串失败: " + e);  
 74         } finally {  
 75             try {  
 76                 if(baos != null) {  
 77                     baos.close();  
 78                     baos = null;  
 79                 }  
 80             } catch (Exception e) {  
 81                 System.out.println("关闭文件流发生异常: " + e);  
 82             }  
 83         }  
 84         return result;  
 85     }  
 87     /** 
 88      * 将BASE64加密字符串转换为图片. 
 89      * @param base64String 
 90      * @param imagePath 图片生成路径. 
 91      * @param format 图片格式. 
 92      */ 
 93     public void convertByteToImage(String base64String, String imagePath, String format) {  
 94         byte[] bytes = null;  
 95         ByteArrayInputStream bais = null;  
 96         BufferedImage bi = null;  
 97         File file = null;  
 98         try {  
 99             bytes = decoder.decodeBuffer(base64String);  
100             bais = new ByteArrayInputStream(bytes);  
101             bi = ImageIO.read(bais);  
102             file = new File(imagePath);  
103             ImageIO.write(bi, format == null ? "jpg" : format, file);  
104             System.out.println("将BASE64加密字符串转换为图片成功！");  
105         } catch (IOException e) {  
106             System.out.println("将BASE64加密字符串转换为图片失败: " + e);  
107         } finally {  
108             try {  
109                 if(bais != null) {  
110                     bais.close();  
111                     bais = null;  
112                 }  
113             } catch (Exception e) {  
114                 System.out.println("关闭文件流发生异常: " + e);  
115             }  
116         }  
117     }  
118 }

然后看测试类：

 1 import java.io.InputStream;  
 3 import com.ilucky.util.image.ImageUtil;  
 5 /** 
 6  * 本事例主要讲了如下几点: 
 7  * 1:将图片转换为BASE64加密字符串. 
 8  * 2:将图片流转换为BASE64加密字符串. 
 9  * 3:将BASE64加密字符串转换为图片. 
10  * 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. 
11  * @author IluckySi 
12  * @since 20150122 
13  */ 
14 public class MainTest {  
16     public static void main(String[] args) {  
17         ImageUtil imageUtil = new ImageUtil();  
19         String base64String = imageUtil.convertImageToByte("D:\\test.png", "png");  
20         System.out.println(base64String);  
21         imageUtil.convertByteToImage(base64String, "D:\\test2.png", "png");  
23         InputStream is = MainTest.class.getResourceAsStream("test.png");  
24         String base64String2 = imageUtil.convertImageStreamToByte(is, "png");  
25         System.out.println(base64String2);  
26         imageUtil.convertByteToImage(base64String2, "D:\\test3.png", "png");  
27     }  
最后看jsp文件:
 1 <!DOCTYPE html>  
 2 <html>  
 3   <head>  
 4     <title>index.html</title>  
 5     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  
 6     <meta http-equiv="description" content="this is my page">  
 7     <meta http-equiv="content-type" content="text/html; charset=UTF-8">  
 8   </head>  
 9   <body>  
10     <!--   
11     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,  
12     逗号后面是image/png文件base64编码后的数据.   
13     data:text/css;base64,base64编码的CSS代码   
14     data:text/javascript,Javascript代码   
15     data:text/javascript;base64,base64编码的Javascript代码   
16     data:image/gif;base64,base64编码的gif图片数据   
17     data:image/png;base64,base64编码的png图片数据   
18     data:image/jpeg;base64,base64编码的jpeg图片数据   
19     data:image/x-icon;base64,base64编码的icon图片数据   
20      -->  
21     <img src="test.png"/>  
22     <img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAFYklEQVR42sVXfUyUdRz/8XKhMZQO  
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47             AABJRU5ErkJggg=="/>   
48   </body>  
49 </html>