调用servlet简单画个框，提示405 Method Not Allowed，急了
package com;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.ImageIcon;

import sun.misc.OSEnvironment;

public class TopologyServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

/**
* 计数器
*/
private static int count = 0;

/**
* 计算的周期 2s
*/
private static final int countPeriod = 2;

/**
* 图像宽度
*/
private static int WIDTH = 800;
/**
* 图像高度
*/
private static int HEIGHT = 400;

//@SuppressWarnings("unused")
private static boolean COLORFUL_LINK = false;

/**
* 设置图片的宽度
* 
* @param w宽度的像素
*/
public void setWidth(int w) {
WIDTH = w;
}

/**
* 设置图片的高度
* 
* @param h高度的像素
*/
public void setHeight(int h) {
HEIGHT = h;
}

/**
* 定时执行并生成图像缓存
*/
public static void OnTimer() {

//ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
count ++;

//多少计算一次
if( !(count % countPeriod ==0) ) return;

try {
COLORFUL_LINK = false;

BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);

Graphics g = image.getGraphics();
g.setColor(Color.WHITE);// 画框
g.fillRect(0, 0, WIDTH, HEIGHT);
g.setColor(Color.GRAY);// 画框
g.drawRect(0, 0, WIDTH-5, HEIGHT-5);

} catch (Exception e) {
// TODO: handle exception
}
}
}


------解决方案--------------------
这个是生成验证码的代码，给你看看：
package com.qhit;

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

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

public class ShowCode extends HttpServlet {

/**
* 
*/
private static final long serialVersionUID = 1L;
private static Logger log = Logger.getLogger(ShowCode.class);
// 设置图形验证码中的字符串的字体的大小

private Font mFont = new Font("Arial Black", Font.PLAIN, 16);


/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
* 
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doPost(request,response);
}

/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*&nbs