将图片转成base64字符串并在JSP页面显示的Java代码详解编程语言

 *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   
                7nmeuwMFwrBEVJqgDOcUHZvNuTarrdKam0zdKrckAy4goowxbaM5hE1yjVVzLjLRokBFz2qsQPGF   
                F8vmamtkL4s4OHDy6ff5EQcXx91hf/jHB777fj8v3+d57p7nOQFA3EuoPxcLhV90SlxziOSeUrHd   
                WRz5fv1uc1fl03OGizdGgmBd/5K5mzNyyO0M4EkEXqBAiI58Ed9WEFp1+MXYm1vW68hKM7AwJR5W   
                mx3RZqsCa/Y4I4dcaqilx10t0PGqCOssEjuvH7H9vW1zEgzNgK5ZYVh02HUN86w65tvGwJo9zhRH   
                cqmhlh70mtEC7a8Ie2ep6dPfW5eM3OnbhMo9S6GbLV6h04Eccqmhlh70omdQC3TsFbbLZaYL/W2Z   
                wA+PYbQ9B780rUJu1nxoMZaAC5BDLjXU0oNe9KS33wXkqRKXXguv+as1HejOxYhzNdwS+G4NjlUs   
                U0cX7+cscEYOudRQSw960ZPezPC9QIE69dv6Pk4exLX1GDm/Cu5z2Qojzmy4WrOxZUOSPELNz9Fr   
                ikMuNR699KInvZkx/sH0WqB9rzCuH5j7Mzrk1uel8HQW3GcmgK+y4axOR0qCVX7gpoazxxk55E7W   
                0oue9GYGs7wXKFCnP7+/cdEovs7GUHMm3C0rvHD7jMTZFSjYugAW89RvAXuckUPuf/X0pDczmMVM   
                zwJyI8v3lVFX7pzLxMiXGXB/sdwncDoDvfXLkJFqh1WbuBSs2eOMnOn09GYGs5g5eYHcXw/HAWcz   
                MfRZOtwSQz7APloexcHdD0GLnVhAlzV7nPnT8j8zmMVMzwKdjtCy/qPJuN0kSY1L/OL250tw61ga   
                Nqy0Q7doCqzZ4yygXmYwi5meBa6Wmk4NNaRgpDEVQ8cX+YVbAk2L0VCcrL52BGv23AG0hMqQWcz0   
                LNBTHtGFkw9D4UQQkLxR+X/LujiF0RMz0xIqc3yBb4sifmp+80G0lCcFhWYJZ0USDu6ar8C6OUit   
                0sssZnoWaNhh+tFqGIg3dM9p9QvJM5t1vP1cvALrmWiZxUzPAidfMLWlJBjqZhKMiRarY+UiAzer   
                5ymwZi8Y7dgNywAzPQuc3xNet3Ypv8+Bn3Y0sUqTQ3k24MM4BdZW3f9zYuKeoYNZzPQscNkRsv35   
                1WbExhoBDXT5zN+4XMcfNVYMv2dTYM0eZ4H0zGAWMz0L9JaK1P1PRQ7EWa0Bn3aJdh2NL2vAEQ2u   
                2jGwZo+zQHq7zJBZrusyc9IZEOEX8sM/yFxokafI8LO9jrx1GgaqY+CujYHr0BhYs5eXoynO9Kff   
                ADOc+eEfyUyT19Owp0SsKd0U5eYrlU+xvMaLk3S0OcxAbTRcB73BHmdpSWNcn5dPejNDZq2d8jiW   
                G4W07Q39JCctVr3T+br2ZY+bcac6CoPvzoGryhvscUaOr88CPenNDGb5fCPqKha2o3kRF1MTKfA+   
                +uxHNNx4IwrDVZFwveMbnJFD7uSzQC960psZft8Je4rFkzXPzh5eME+HTTfUs94mbxx1W+cCVbMw   
                uH82XNOAM3LIpUZppQe96EnvoN6K5TXaVfPMbCxO1BAVbeCJzBj89tYsDO+/DwOVEX5BDrmbpYZa   
                etCLnkG/ll8qEqK7WOQe32lybs54AKd23I/RA+EYqDAFBXJPSg219KAXPWf8y+iKQxhXHaLyRklI   
                363yUAzsC8OghGtfqE9wRg651FBLj7v/aTb+ul4oUi4VipIuh+i+WSKG+spC8Gd5CPr/BWv2OJOc   
                Hsl9XWoW/v/fht5LhLUXiARZb71cJOquFIlv5BH2EqzZ40xyEsm9OJMfp/cS/wC6xRqbyM2GFQAA   
                AABJRU5ErkJggg=="/>    
      </body>   
    </html>  

部署项目，启动服务器,访问jsp页面,会看到浏览器上有两张一样的图片.