drawvote.java

一本jsp自学教材

package test;

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.sun.image.codec.jpeg.*;
import java.awt.image.*;
import java.awt.*;
import javax.imageio.ImageIO;

public class DrawVote extends HttpServlet {
   
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException
    {        
        response.setContentType("image/jpeg;charset=GBK");
        try{
           String hl=request.getParameter("hl");
           String co=request.getParameter("color");
           int wid=Integer.parseInt(hl);
           int col=Integer.parseInt(co);

           BufferedImage image = new BufferedImage(wid+20,16, BufferedImage.TYPE_INT_RGB);      
           Graphics g = image.getGraphics();
           g.setColor(Color.white);
           g.fillRect(0, 0, wid+20,16);       
           // 设置背景色
           g.setColor(getRandomColor(col));
           g.fillRect(0, 0, wid,16);
           String num=String.valueOf(wid/4);
           g.setColor(Color.black);
           g.drawString(num,wid,13); 

      g.dispose();// 图象生效

      // 输出图象到页面
      ImageIO.write(image, "JPEG", response.getOutputStream());
       }  
     catch(Exception e)
          {
            PrintWriter out = response.getWriter();
            out.print(e.toString()); 
          }       
    } 
    //获取随机颜色
    Color getRandomColor(int col)
      {   
        Color cc=new Color(5);
        if(col>5)     
         col=col%5;
        if(col==1) 
          cc=Color.red;
        if(col==2) 
          cc=Color.green;
        if(col==3) 
          cc=Color.gray;
        if(col==4) 
          cc=Color.blue;
        if(col==4) 
          cc=Color.cyan;
        return cc;
      } 
    public void doPost(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException
    {  
      doGet(request,response);    
    }   
   public void destroy()
    {
    }
}