這是一個公用文件
package com.zeroidea.common;

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

public class MakeImageAndVerifyCode {

?private java.lang.String verifyCode;

?private java.awt.image.BufferedImage image;

?/**
? * 構建器
? */
?public MakeImageAndVerifyCode() {
??verifyCode = "";
??image = new BufferedImage(60, 20, BufferedImage.TYPE_INT_RGB);
??makeImageAndVerifyCode();
?}

?/**
? * 設置驗證碼
? *
? * @param verifyCode
? */
?private void setVerifyCode(java.lang.String verifyCode) {
??this.verifyCode = verifyCode;
?}

?/**
? * 生成器
? */
?private void makeImageAndVerifyCode() {
??Graphics graphics = image.getGraphics();
??graphics.fillRect(0, 0, 60, 20);
??java.lang.String nowChar = "";
??graphics.setFont(new Font("Times New Roman", 1, 12));
??for (int i = 0; i < 4; i++) {
???java.lang.String nowCharTemp = getRandInt(10).toString();
???graphics.setColor(getRandColor(100, 200));
???graphics.drawString(nowCharTemp, 1 + i * 15
?????+ getRandInt(7).intValue(), 12 + getRandInt(8).intValue());
???nowChar = (new StringBuilder(java.lang.String.valueOf(nowChar)))
?????.append(nowCharTemp).toString();
??}

??for (int i = 0; i < 88; i++) {
???graphics.setColor(getRandColor(225, 255));
???java.awt.Point point = getRandPoint(60, 20);
???graphics.drawOval(point.x, point.y, 0, 0);
??}

??graphics.setColor(getRandColor(0, 255));
??graphics.drawRect(0, 0, 59, 19);
??graphics.dispose();
??setVerifyCode(nowChar);
?}

?/**
? * 返回驗證代碼
? *
? * @return String
? */
?public java.lang.String getVerifyCode() {
??return verifyCode;
?}

?/**
? * 返回驗證代碼圖片
? *
? * @return BufferedImage
? */
?public java.awt.image.BufferedImage getImage() {
??return image;
?}

?/**
? * 生成隨機顏色
? *
? * @param fc
? * @param bc
? * @return Color
? */
?private java.awt.Color getRandColor(int fc, int bc) {
??java.util.Random random = new Random();
??if (fc > 255)
???fc = 255;
??if (bc > 255)
???bc = 255;
??int r = fc + random.nextInt(bc - fc);
??int g = fc + random.nextInt(bc - fc);
??int b = fc + random.nextInt(bc - fc);
??return new Color(r, g, b);
?}

?/**
? * 生成隨機數
? *
? * @param i
? * @return Integer
? */
?private java.lang.Integer getRandInt(int i) {
??java.util.Random random = new Random();
??return java.lang.Integer.valueOf(random.nextInt(i));
?}

?/**
? * 生成隨機點
? *
? * @param x
? * @param y
? * @return Point
? */
?private java.awt.Point getRandPoint(int x, int y) {
??java.util.Random random = new Random();
??int x_temp = random.nextInt(x);
??int y_temp = random.nextInt(y);
??java.awt.Point point = new Point(x_temp, y_temp);
??return point;
?}
}


生成驗證圖片并將驗證碼寫入 Session
/**
?* 驗證圖片產生
?* 作者: 劉萬林
?*/

package com.zeroidea.pwms.validate;

import java.awt.image.BufferedImage;
import java.io.IOException;

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

import com.zeroidea.common.MakeImageAndVerifyCode;

public class ValidateImage extends HttpServlet {

?/**
? *
? */
?private static final long serialVersionUID = 1L;

?/**
? * Constructor of the object.
? */
?public ValidateImage() {
??super();
?}

?/**
? * Destruction of the servlet. <br>
? */
?public void destroy() {
??super.destroy(); // Just puts "destroy" string in log
??// Put your code here
?}

?/**
? * 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 {
??response.setHeader("Pragma", "No-cache");
??response.setHeader("Cache-Control", "no-cache");
??response.setDateHeader("Expires", 0);
??MakeImageAndVerifyCode makeImageAndVerifyCode = new MakeImageAndVerifyCode();
??BufferedImage image = makeImageAndVerifyCode.getImage();
??String verifyCode = makeImageAndVerifyCode.getVerifyCode();
??//System.out.println(verifyCode);
??// 將驗證碼寫入 Session
??request.getSession().setAttribute("verifyCode", verifyCode);
??// 以下語句將圖像寫入 響應輸出流
??ImageIO.write(image, "JPEG", response.getOutputStream());
?}

?/**
? * Initialization of the servlet. <br>
? *
? * @throws ServletException if an error occure
? */
?public void init() throws ServletException {
??// Put your code here
?}

}


效果圖: