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>