验证码

package com.hand.controller.system.secCode;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.http.HttpServletResponse;import 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.hand.util.Const;@Controller@RequestMapping("/code")public class SecCodeController {@RequestMappingpublic 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);                //public static final String SESSION_SECURITY_CODE = "sessionSecCode";    //验证码try {ServletOutputStream out = response.getOutputStream();output.writeTo(out);out.close();} catch (IOException e) {//e.printStackTrace();}}private String drawImg(ByteArrayOutputStream output){String code = "";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);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;}private char randomChar(){Random r = new Random();String s = "ABCDEFGHJKLMNPRSTUVWXYZ0123456789";return s.charAt(r.nextInt(s.length()));}}