【Java】登录操作中随机生成验证码的工具类
效果图：
工具类CreateImageCode.java：
import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; import java.util.Random; import javax.imageio.ImageIO; public class CreateImageCode { private int width = 70; private int height = 27; private int codeCount = 4; // 干扰线数 //private int lineCount = 10; // 验证码图片Buffer // 验证码 private String code = null; public String getCode() { return code; } public void setCode(String code) { this.code = code; } private BufferedImage buffImg = null; Random random = new Random(); public CreateImageCode() { createImage(); } public CreateImageCode(int width, int height) { this.width = width; this.height = height; createImage(); } public CreateImageCode(int width, int height, int codeCount) { this.width = width; this.height = height; this.codeCount = codeCount; createImage(); } public CreateImageCode(int width, int height, int codeCount, int lineCount) { this.width = width; this.height = height; this.codeCount = codeCount; //this.lineCount = lineCount; createImage(); } // 生成图片 private void createImage() { int fontWidth = width / codeCount;// 字体宽度。 int fontHeight = height - 5;// 字体高度。 int codeY = height - 8; // 得到图片 buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = buffImg.getGraphics(); // 设置背景色 g.setColor(getRandColor(249, 250)); g.fillRect(0, 0, width, height); // 设置边框 //g.setColor(getRandColor(200, 250)); //g.drawRect(1, 1, width - 2, height - 2); // 设置字体 Font font = new Font("Fixedsys", Font.PLAIN, fontHeight); g.setFont(font); /*// 设置干扰线 for (int i = 0; i < lineCount; i++) { int x1 = random.nextInt(width); int y1 = random.nextInt(height); int x2 = random.nextInt(width); int y2 = random.nextInt(height); g.setColor(getRandColor(1, 255)); g.drawLine(x1, y1, x2, y2); }*/ /*// 添加噪点 float yawpRate = 0.01f;// 噪声率 int area = (int) (yawpRate * width * height); for (int i = 0; i < area; i++) { int x = random.nextInt(width); int y = random.nextInt(height); buffImg.setRGB(x, y, random.nextInt(255)); }*/ String str1 = randomStr(codeCount);// 得到随机字符 this.code = str1; for (int i = 0; i < codeCount; i++) { String strRand = str1.substring(i, i + 1); g.setColor(getRandColor(50, 250)); // g.drawString(a,x,y); // a为要画出来的东西，x和y表示要画的东西最左侧字符的基线位于此图形上下文坐标系的 (x, y) 位置处 g.drawString(strRand, i * fontWidth + 3, codeY); } } // 得到随机字符 private String randomStr(int n) { String str1 = "1234567890"; String str2 = ""; int len = str1.length() - 1; double r; for (int i = 0; i < n; i++) { r = (Math.random()) * len; str2 = str2 + str1.charAt((int) r); } return str2; } // 得到随机颜色 private Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色 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); } public void write(OutputStream sos) throws IOException { ImageIO.write(buffImg, "png", sos); sos.close(); } }
在servlet中使用此工具类，输出验证码到网页：
package com.utils; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet(name = "GetImageCodeServlet",urlPatterns = {"/servlet/code.servlet"}) public class GetImageCodeServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request,response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("image/jepg"); // 控制浏览器不要缓存 response.setDateHeader("expries", -1); response.setHeader("Cache-Control", "no-cache"); response.setHeader("Pragma", "no-cache"); // 创建图片 CreateImageCode image = new CreateImageCode(); String str = image.getCode(); // 存入Session // System.out.println("验证码为"+str); request.getSession().setAttribute("code",str); // 输出到网页 image.write(response.getOutputStream()); } }
JSP中在表单显示此图片（演示时不使用Ajax，直接将form提交到另一个servlet判断）：
<form action="${pageContext.request.contextPath}/servlet/codeTest.servlet"> <input type="text" name="code"> <img src="${pageContext.request.contextPath}/servlet/code.servlet" onclick="javascript:this.src='${pageContext.request.contextPath}/servlet/code.servlet?rm='+Math.random()" alt="获取验证码"> <input type="submit" value="验证"> </form>
后台验证验证码的servlet：
package com.utils; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet(name = "CodeTestServlet" ,urlPatterns = {"/servlet/codeTest.servlet"}) public class CodeTestServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request,response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String code = request.getParameter("code"); if (code.equals(request.getSession().getAttribute("code"))) { System.out.println("验证成功，验证码为：" + request.getSession().getAttribute("code")); // response.sendRedirect(getServletContext().getContextPath()+"/login.jsp"); }else{ System.out.println("验证失败"); } } }
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使用的是3.0的注解开发，web.xml中不需配置
若为maven项目，依赖为：
<dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> <version>2.3.1</version> </dependency>
