voteimage.java

jsp源代码,一起学jsp,比较好的jsp源代码,入门与深入

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

public class VoteImage extends HttpServlet
{
   private String strFile = null;
   private Color color[]={Color.red,Color.black,Color.orange,Color.green};
   private int baseAng=30;

   public void doGet(HttpServletRequest request,HttpServletResponse response)
               throws ServletException,IOException
   {
      strFile = request.getRealPath("count.txt");
      float[][] xy = new float[4][2];
      xy = getNumAndPercent(strFile);
      int[] ang = new int[4];
      ang[0] = (int)(xy[0][1]*360);
      ang[1] = (int)(xy[1][1]*360);
      ang[2] = (int)(xy[2][1]*360);
      ang[3] = 360-ang[0]-ang[1]-ang[2];

      response.setHeader("Cache-Control","no-store");
      response.setDateHeader("Expires",0);
      response.setContentType("image/jpeg");
      ServletOutputStream out=response.getOutputStream();
      BufferedImage image = new BufferedImage ( 180 , 120 , BufferedImage. TYPE_INT_RGB);
      Graphics2D g = (Graphics2D)image.getGraphics();
      g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
      g.setColor(Color.white);
      g.fillRect(0,0,180,120);
      AffineTransform at = null;
      Arc2D arc = null;
      int fromAng = baseAng;
      at = AffineTransform.getRotateInstance((-20*java.lang.Math.PI)/180,45,37);
      g.setTransform(at);
      int r =6;
      //int dx = (int) ( r * java.lang.Math.cos ( ( baseAng + ang[0] ) / 2.0 * java.lang.Math.PI / 180 ) );
      //int dy = ( int ) ( r * java.lang.Math.sin (( baseAng + ang[0] ) / 2.0 * java.lang.Math.PI / 180 ) );
      arc = new Arc2D.Double(10,24,96,60,fromAng,ang[0],Arc2D.PIE);
      g.setColor(color[0]);
      g.fill(arc);
      fromAng+=ang[0];
      //绘制圆饼比例图
      for(int i=1;i<4;i++) 
      {
        g.setColor(color[i]);
        arc = new Arc2D.Double(10,24,96,60,fromAng,ang[i],Arc2D.PIE);
        g.fill(arc);
        fromAng+=ang[i];  
        if(fromAng>360)
        {
           fromAng-=360;
        }
      }
      at = AffineTransform.getRotateInstance(0,arc.getCenterX(),arc.getCenterY());
      g.setTransform(at);
      //绘制圆饼图的说明
      for (int i=0;i<4;i++)
      {
         g.setColor(color[i]);
         g.fillRect(130,15*i+20,10,10);
         g.drawString((char)('A'+i)+" "+String.valueOf(new Float(xy[i][0]).intValue()),150,15*i+20+10);  
      }
      JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
      encoder.encode(image);
      out.close();
   }

   public void doPost(HttpServletRequest request,HttpServletResponse response)
               throws ServletException,IOException
   {
      doGet(request,response);
   }
   //根据投票情况得到各项票数所占的比例数
   public synchronized float[][] getNumAndPercent(String sFileName)
   {
      float xx[][] = new float[4][2];
      int totalNum = 0 ;  
      String strTemp = null;  
      int i = 0;
      java.io.RandomAccessFile rf = null;
      try
      {
         rf = new java.io.RandomAccessFile (sFileName,"r");
      }catch(Exception e)
      {
         System.out.println(e);
         System.exit(0);
      }
      for (i=0;i<4;i++)
      {
         int m=0;
         try {
                strTemp = rf.readLine();
         } catch (Exception e){
            strTemp = "0";
         }
         if (strTemp == null) strTemp = "0";
         m = new Integer(strTemp).intValue();
         xx[i][0]=m;
         totalNum += m;
      }
      if (totalNum==0) totalNum=1;
      for ( i=0;i<4;i++)
      {
         xx[i][1] = xx[i][0]/totalNum;
      }
      return xx;
   }
}