Javaを使用してバックグラウンド検証コードを生成する

验证码：      /** * 校验字段是否为空 */ function checkNull(name,msg){ setMsg(name,"") var v = document.getElementsByName(name)[0].value; if(v == ""){ setMsg(name,msg) return false; } return true; } /** * 为输入项设置提示消息 */ function setMsg(name,msg){ var span = document.getElementById(name+"_msg"); span.innerHTML=""+msg+""; } /** * 点击更换验证码 */ function changeYZM(imgObj){ imgObj.src = "${pageContext.request.contextPath}/servlet/ValiImgServlet?time="+new Date().getTime(); }

package cn.tedu.web; import cn.tedu.util.VerifyCode; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; /** * 获取验证码 */ public class ValiImgServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //禁止浏览器缓存验证码 response.setDateHeader("Expires",-1); response.setHeader("Cache-Control","no-cache"); response.setHeader("Pragma","no-cache"); //生成验证码 VerifyCode vc = new VerifyCode(); //输出验证码 vc.drawImage(response.getOutputStream()); //获取验证码的值，存储到session中 String valistr = vc.getCode(); HttpSession session = request.getSession(); session.setAttribute("valistr",valistr); //打印到控制台 System.out.println(valistr); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } }

package cn.tedu.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.OutputStream; import java.util.Random; import javax.imageio.ImageIO; /** * 动态生成图片 */ public class VerifyCode { // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"} private static String[] fontNames = { "宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312" }; // 可选字符 //"23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ"; private static String codes = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ"; // 背景色 private Color bgColor = new Color(255, 255, 255); // 基数(一个文字所占的空间大小) private int base = 30; // 图像宽度 private int width = base * 4; // 图像高度 private int height = base; // 文字个数 private int len = 4; // 设置字体大小 private int fontSize = 22; // 验证码上的文本 private String text; private BufferedImage img = null; private Graphics2D g2 = null; /** * 生成验证码图片 */ public void drawImage(OutputStream outputStream) { // 1.创建图片缓冲区对象, 并设置宽高和图像类型 img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 2.得到绘制环境 g2 = (Graphics2D) img.getGraphics(); // 3.开始画图 // 设置背景色 g2.setColor(bgColor); g2.fillRect(0, 0, width, height); StringBuffer sb = new StringBuffer();// 用来装载验证码上的文本 for (int i = 0; i < len; i++) { // 设置画笔颜色 -- 随机 // g2.setColor(new Color(255, 0, 0)); g2.setColor(new Color(getRandom(0, 150), getRandom(0, 150),getRandom(0, 150))); // 设置字体 g2.setFont(new Font(fontNames[getRandom(0, fontNames.length)], Font.BOLD, fontSize)); // 旋转文字(-45~+45) int theta = getRandom(-45, 45); g2.rotate(theta * Math.PI / 180, 7 + i * base, height - 8); // 写字 String code = codes.charAt(getRandom(0, codes.length())) + ""; g2.drawString(code, 7 + i * base, height - 8); sb.append(code); g2.rotate(-theta * Math.PI / 180, 7 + i * base, height - 8); } this.text = sb.toString(); // 画干扰线 for (int i = 0; i < len + 2; i++) { // 设置画笔颜色 -- 随机 // g2.setColor(new Color(255, 0, 0)); g2.setColor(new Color(getRandom(0, 150), getRandom(0, 150), getRandom(0, 150))); g2.drawLine(getRandom(0, 120), getRandom(0, 30), getRandom(0, 120), getRandom(0, 30)); } //TODO: g2.setColor(Color.GRAY); g2.drawRect(0, 0, this.width-1, this.height-1); // 4.保存图片到指定的输出流 try { ImageIO.write(this.img, "JPEG", outputStream); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException(e); }finally{ // 5.释放资源 g2.dispose(); } } /** * 获取验证码字符串 * @return */ public String getCode() { return this.text; } /* * 生成随机数的方法 */ private static int getRandom(int start, int end) { Random random = new Random(); return random.nextInt(end - start) + start; } /*public static void main(String[] args) throws Exception { VerifyCode vc = new VerifyCode(); vc.drawImage(new FileOutputStream("f:/vc.jpg")); System.out.println("执行成功~!"); }*/ }