SpringMVC系列之开发登录界面的验证码

SpringMVC系列之开发登录界面的验证码

本博客介绍如何开发登录界面的验证码

先写个验证码生成的Controller类:

package com.appweb.controller.login;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.font.FontRenderContext;import java.awt.geom.Rectangle2D;import java.awt.image.BufferedImage;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletOutputStream;import javax.servlet.org.apache.shiro.SecurityUtils;import org.apache.shiro.session.Session;import org.apache.shiro.subject.Subject;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import com.appweb.core.base.Const;@Controller@RequestMapping("/code")public class SecCodeController { @RequestMapping public void generate(HttpServletResponse response){ ByteArrayOutputStream output = new ByteArrayOutputStream(); String code = drawImg(output); Subject currentUser = SecurityUtils.getSubject(); Session session = currentUser.getSession(); session.setAttribute(Const.SESSION_SECURITY_CODE, code); try { ServletOutputStream out = response.getOutputStream(); output.writeTo(out); } catch (IOException e) { e.printStackTrace(); } } /** * 绘画验证码 * @param output * @return */ private String drawImg(ByteArrayOutputStream output){ String code = ""; //随机产生4个字符 for(int i=0; i<4; i++){ code += randomChar(); } int width = 70; int height = 25; BufferedImage bi = new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR); Font font = new Font("Times New Roman",Font.PLAIN,20); //调用Graphics2D绘画验证码 Graphics2D g = bi.createGraphics(); g.setFont(font); Color color = new Color(66,2,82); g.setColor(color); g.setBackground(new Color(226,226,240)); g.clearRect(0, 0, width, height); FontRenderContext context = g.getFontRenderContext(); Rectangle2D bounds = font.getStringBounds(code, context); double x = (width - bounds.getWidth()) / 2; double y = (height - bounds.getHeight()) / 2; double ascent = bounds.getY(); double baseY = y - ascent; g.drawString(code, (int)x, (int)baseY); g.dispose(); try { ImageIO.write(bi, "jpg", output); } catch (IOException e) { e.printStackTrace(); } return code; } /** * 随机参数一个字符 * @return */ private char randomChar(){ Random r = new Random(); String s = "ABCDEFGHJKLMNPRSTUVWXYZ0123456789"; return s.charAt(r.nextInt(s.length())); }}

引入jQuery.js:

用jquery写个函数：

function genTimestamp() { var time = new Date(); return time.getTime(); }

function changeCode() { $("#Img").attr("src", "code.do?t=" + genTimestamp()); }

写个img标签调用函数：

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