- java隨機產生驗證碼,可以隨機生成數字、大寫字母、小寫字母。還可以隨機生成文字字體、及大小。在圖片上面可能字體都不不同、大小不等。
- package com.hoo.util;
- import java.awt.Color;
- import java.awt.Font;
- import java.awt.Graphics;
- import java.awt.image.BufferedImage;
- import java.util.Random;
- import javax.imageio.ImageIO;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- /**
- * <b>function:</b> 驗證碼生成工具類
- * @project NetWorkService
- * @package com.hoo.util
- * @fileName ValidCodeUtils.java
- * @createDate 2010-8-3 下午03:05:50
- * @author hoojo
- */
- @SuppressWarnings("unused")
- public class ValidCodeUtils {
- /*********************************************************************
- * 驗證碼寬度
- */
- public static int WIDTH = 60;
- /***
- * 驗證碼高度
- */
- public static int HEIGHT = 20;
- /**********************************************************************
- * 驗證碼背景顏色COLOR_FC_BG 應當小於COLOR_BC_BG
- */
- public static int COLOR_FC_BG = 200;
- /***
- * 驗證碼背景顏色COLOR_FC_BG 應當小於COLOR_BC_BG
- */
- public static int COLOR_BC_BG = 250;
- /**********************************************************************
- * 驗證碼背景干擾線顏色COLOR_FC_LINE 應當小於COLOR_BC_LINE
- */
- public static int COLOR_FC_LINE = 160;
- /***
- * 驗證碼背景干擾線顏色COLOR_FC_LINE 應當小於COLOR_BC_LINE
- */
- public static int COLOR_BC_LINE = 200;
- /***************************************************************************
- * 驗證碼顏色COLOR_FC_CODE 應當小於COLOR_BC_CODE
- */
- public static int COLOR_FC_CODE = 20;
- /***
- * 驗證碼顏色COLOR_FC_CODE 應當小於COLOR_BC_CODE
- */
- public static int COLOR_BC_CODE = 170;
- /***************************************************************************
- * 生成在指定範圍內的顏色
- * @param fc 範圍fc color值 小於255
- * @param bc 範圍bc color值 小於255
- * @return Color
- */
- private static Color getRandColor(int fc, int bc) {
- Random random = new Random();
- if (fc < 0)
- fc = 0;
- if (bc < 0)
- bc = 1;
- if (fc > 255)
- fc = 255;
- if (bc > 255)
- bc = 255;
- if (bc == fc)
- bc += 10;
- int temp = 0;
- if (bc < fc) {
- temp = bc;
- bc = fc;
- fc = temp;
- }
- 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);
- }
- /**
- * <b>function:</b> 生成圖片方法
- * @createDate 2010-8-3 下午03:06:22
- * @author hoojo
- * @param request HttpServletRequest
- * @param response HttpServletResponse
- * @return boolean
- * @throws Exception
- */
- public static boolean getImage(HttpServletRequest request, HttpServletResponse response) throws Exception{
- response.reset();
- response.setContentType("image/jpeg");
- // 設置頁面不緩存
- response.setHeader("Pragma", "No-cache");
- response.setHeader("Cache-Control", "no-cache");
- response.setDateHeader("Expires", 0);
- // 在內存中創建圖象
- BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
- // 獲取圖形上下文
- Graphics img = image.getGraphics();
- // 生成隨機類
- Random random = new Random();
- // 設定背景色
- img.setColor(getRandColor(COLOR_FC_BG, COLOR_BC_BG));
- img.fillRect(0, 0, WIDTH, HEIGHT);
- // 設定字體
- img.setFont(new Font("Times New Roman", Font.PLAIN, 18));
- // 畫邊框
- // g.setColor(new Color());
- // g.drawRect(0,0,width-1,height-1);
- // 隨機產生155條幹擾線,使圖象中的認證碼不易被其它程序探測到
- img.setColor(getRandColor(COLOR_FC_LINE, COLOR_BC_LINE));
- for (int i = 0; i < 155; i++) {
- int x = random.nextInt(WIDTH);
- int y = random.nextInt(HEIGHT);
- int xl = random.nextInt(12);
- int yl = random.nextInt(12);
- img.drawLine(x, y, x + xl, y + yl);
- }
- // 取隨機產生的認證碼(4位數字)
- String codeValue = "";
- for (int i = 0; i < 4; i++) {
- //String rand = String.valueOf(random.nextInt(10));
- String rand = getRandomChar();
- codeValue = codeValue.concat(rand);
- img.setFont(getRandomFont());//隨機字體
- // 將認證碼顯示到圖象中
- img.setColor(getRandColor(COLOR_FC_CODE, COLOR_BC_CODE));
- img.drawString(rand, 13 * i + 6, 16);
- }
- request.getSession().setAttribute("codeValue", codeValue);
- // 圖象生效
- img.dispose();
- // 輸出圖象到頁面
- return ImageIO.write(image, "JPEG", response.getOutputStream());
- }
- /**
- * 隨機生成字符,含大寫、小寫、數字
- * <b>function:</b> 功能
- * @createDate 2010-8-23 上午10:33:55
- * @author hoojo
- * @return
- */
- public static String getRandomChar() {
- int index = (int) Math.round(Math.random() * 2);
- String randChar = "";
- switch (index) {
- case 0://大寫字符
- randChar = String.valueOf((char)Math.round(Math.random() * 25 + 65));
- break;
- case 1://小寫字符
- randChar = String.valueOf((char)Math.round(Math.random() * 25 + 97));
- break;
- default://數字
- randChar = String.valueOf(Math.round(Math.random() * 9));
- break;
- }
- return randChar;
- }
- /**
- * <b>function:</b> 隨機生成字體、文字大小
- * @createDate 2010-8-23 上午10:44:22
- * @author hoojo
- * @return
- */
- public static Font getRandomFont() {
- String[] fonts = {"Georgia", "Verdana", "Arial", "Tahoma", "Time News Roman", "Courier New", "Arial Black", "Quantzite"};
- int fontIndex = (int)Math.round(Math.random() * (fonts.length - 1));
- int fontSize = (int) Math.round(Math.random() * 4 + 16);
- return new Font(fonts[fontIndex], Font.PLAIN, fontSize);
- }
- }
其中驗證碼的值是保存在session中:request.getSession().setAttribute("codeValue", codeValue);
比較用戶輸入的值和session中的codeValue是否相等即可;
下面是jsp頁面調用servlet:ValidCodeServlet.java
ValidCodeServlet中調用了上面的ValidCodeUtils 驗證碼生成工具類
- package com.hoo.servlet;
- import java.io.IOException;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import com.hoo.util.ValidCodeUtils;
- @SuppressWarnings("serial")
- public class ValidCodeServlet extends HttpServlet {
- public void doGet(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- try {
- ValidCodeUtils.getImage(request, response);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- public void doPost(HttpServletRequest request, HttpServletResponse response)
- throws ServletException, IOException {
- doGet(request, response);
- }
- }
jsp頁面調用servlet方法即可
- js:reloadValidCode方法
- function reloadValidCode(o) {
- o.src = "${pageContext.request.contextPath }/validCodeServlet?timed=" + new Date().getMilliseconds();
- }
- 這裏的"timed=" + new Date().getMilliseconds();是需要防止IE緩存用的
- html標籤:
- <img src="${pageContext.request.contextPath }/validCodeServlet" title="看不清,點擊刷新" onclick="reloadValidCode(this)"/>
- 直接跟Servlet名稱配置的url即可,和web.xml配置對應。主要調用路徑${pageContext.request.contextPath }/validCodeServlet這樣會帶上根目錄,比較保險。
- web.xml中validCodeServlet配置
- <servlet>
- <servlet-name>validCodeServlet</servlet-name>
- <servlet-class>com.hoo.servlet.ValidCodeServlet</servlet-class>
- </servlet>
- <servlet-mapping>
- <servlet-name>validCodeServlet</servlet-name>
- <url-pattern>/validCodeServlet</url-pattern>
- </servlet-mapping>
至此,整個圖片驗證碼就配置完畢。在瀏覽器中輸入你請求的url,在jsp頁面中就可以看到效果
怎樣,效果還很理想吧。字體、大小、數字、大小寫字符、及顏色等!