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  
            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>