Spring MVC可使用的AbstractJpegView

这和AbstractExcelView,AbstractPdfView不同，此类是实现View接口，实现自定义的视图解析

 

package  Action;

import  java.awt.image.BufferedImage;
import  java.util.Map;

import  javax.servlet.ServletOutputStream;
import  javax.servlet.http.HttpServletRequest;
import  javax.servlet.http.HttpServletResponse;

import  org.springframework.web.servlet.View;

import  sun.awt.image.codec.JPEGImageEncoderImpl;

import  com.sun.image.codec.jpeg.JPEGImageEncoder;

public   abstract   class  AbstractJpegView  implements  View  ... {

    public String getContentType() ...{
        // TODO 自动生成方法存根
        return null;
    }
    public int getImageWidth()...{return 100;}
    public int getImageHeght()...{return 100;}
    protected int getImageType()...{
        return BufferedImage.TYPE_INT_RGB;
    }
    public void render(Map map, HttpServletRequest request,
            HttpServletResponse response) throws Exception ...{
       response.setContentType("image/jpeg");//设置内容类型
       BufferedImage image=new BufferedImage(this.getImageWidth(),this.getImageHeght(),this.getImageType());//缓存图像
       buildImage(map,image,request,response);//绘制图像
       //编码图像
       ServletOutputStream out=response.getOutputStream();
       JPEGImageEncoder encoder=new JPEGImageEncoderImpl(out);
       encoder.encode(image);
       out.flush();
       
       
    }
    protected abstract void buildImage(Map model,BufferedImage image,HttpServletRequest request,HttpServletResponse response) throws Exception;

}

 我们只要继承这个类，实现buildImage方法，就可以输出人以jpeg图像了，下面是一个画圆的简单实现

 

package  Action;

import  java.awt.Graphics;
import  java.awt.image.BufferedImage;
import  java.util.Map;

import  javax.servlet.http.HttpServletRequest;
import  javax.servlet.http.HttpServletResponse;

public   class  CircleJpegView  extends  AbstractJpegView  ... {

    
    protected void buildImage(Map model, BufferedImage image,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception ...{
        //画圆
        Graphics g=image.getGraphics();
        g.drawOval(0,0, this.getImageWidth(), this.getImageHeght());

    }

    

}