authimg.java

是一个网站的博客系统

package com.opensource.blog.web.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.laoer.comm.util.Util;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class AuthImg
    extends HttpServlet {

  private static final String CONTENT_TYPE = "text/html; charset=GBK";

  private Font mFont = new Font("Times New Roman", Font.PLAIN, 12);

  //Initialize global variables
  public void init() throws ServletException {
  }

  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    String s = Util.genNumPassword(4);
    HttpSession session = request.getSession();
    session.setAttribute("authcode", s);

    response.setContentType("image/jpeg");
    ServletOutputStream out = response.getOutputStream();
    BufferedImage image = new BufferedImage(35, 14, BufferedImage.TYPE_INT_RGB);
    Graphics gra = image.getGraphics();
    gra.setColor(Color.yellow);
    gra.fillRect(1, 1, 33, 12);
    gra.setColor(Color.black);
    gra.setFont(mFont);

    char c;
    for (int i = 0; i < 4; i++) {
      c = s.charAt(i);
      gra.drawString(String.valueOf(c), i * 7 + 4, 11);
    }

    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
    encoder.encode(image);
    out.close();
  }

  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    doGet(request, response);
  }

  //Clean up resources
  public void destroy() {
  }
}