标签：.text 指定 sign 对象 tput iter any 绘制 pre
1、环境：Win7x64、eclipse-jee-mars-R-win32__apk__20180122_1457、JDK1.8
2、知识点：
（1）、Session 使用
ZC：貌似使用 很简单... request.getSession() 貌似获取的就是 本request关联的Session，这样 就不需要再弄 Map之类的来关联了，直接用就行了...
（2）、Cookie使用
看到 "test_yzm.html"和"TservletLogon"中 有 获取 和 设置(通过response相应头来设置) Cookie的方式
（3）、动态图片验证码
"3.4"里面的就是 验证码相关的 代码
3、代码：
3.1、test_yzm.html
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>测试图片验证码</title> </head> <body> <% // JavaWeb实现登录验证码 - 梦蓝樱飞(一点一滴, 记录个人成长之路) - CSDN博客.html（https://blog.csdn.net/menglanyingfei/article/details/79101580） String ContextPath = request.getContextPath(); //String message = request.getParameter("message"); //String imageMess = request.getParameter("imageMess"); //String error = request.getParameter("error"); String message = (String)request.getAttribute("message"); String imageMess = (String)request.getAttribute("imageMess"); String error = (String)request.getAttribute("error"); System.out.println("JSP- message : "+message); System.out.println("JSP- imageMess : "+imageMess); System.out.println("JSP- error : "+error); // 获取浏览器发送过来的cookie, 获取用户信息 Cookie[] cookies = request.getCookies(); String username = ""; if (cookies != null) { for (Cookie cookie : cookies) { if ("username".equals(cookie.getName())) username = cookie.getValue(); } } %> <font color="red"><%= message%></font> <form action="<%= ContextPath%>/servletLogon" method="post"> 用户名:<input type="text" name="username" value="<%= username%>"><font color="red"><%= error%></font><br> 密码:<input type="password" name="password"><br> 验证码:<input type="text" name="image"> <img src="<%= ContextPath%>/servletVerifyCode"><input type="button" value="看不清? 换一张." id="btnVerifyCode"><font color="red"><%= imageMess%></font><br> <input type="submit" value="登录"> </form> <script type="text/javascript"> document.getElementById("btnVerifyCode").onclick = function() { // 获取img元素 // 为了让浏览器发送请求到servlet, 所以一定要改变src document.getElementsByTagName("img")[0].src = "<%= ContextPath%>/servletVerifyCode?time=" + (new Date()).getTime(); }; </script> </body> </html>
3.2、TservletLogon.java
package zzz.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/servletLogon") public class TservletLogon extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // response.getWriter().append("Served at: ").append(request.getContextPath()); System.out.println("image : " + request.getParameter("image")); System.out.println("username : " + request.getParameter("username")); System.out.println("password : " + request.getParameter("password")); System.out.println(""); String imageText = request.getParameter("image"); // 图片的验证码 String text = (String) request.getSession().getAttribute("text"); System.out.println("text : " + text); if (! text.equalsIgnoreCase(imageText)) { request.setAttribute("imageMess", "验证码输入错误!"); request.getRequestDispatcher("/test_yzm.jsp").forward(request, response); return; } // 获取用户名和密码 String username = request.getParameter("username"); String password = request.getParameter("password"); if ("haha".equals(username) && "123".equals(password)) { // 将用户信息保存到session中 request.getSession().setAttribute("username", username); // 使用cookie实现回写用户名 Cookie cookie = new Cookie("username", username); cookie.setMaxAge(60 * 60); // 通过响应头发送cookie response.addCookie(cookie);
// 重定向登录成功界面 response.sendRedirect( request.getContextPath() + "/logOK.jsp" ); } else { request.setAttribute("error", "用户名或密码错误!"); request.getRequestDispatcher("/test_yzm.jsp").forward(request, response); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
3.3、logOK.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>登录 成功</title> </head> <body> 登录 成功 </body> </html>
3.4、图片 验证码 相关
（1）TservletVerifyCode.java
package zzz.servlet; import java.awt.image.BufferedImage; import java.io.IOException; 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 wx.VerifyCode.TverifyCode; @WebServlet("/servletVerifyCode") public class TservletVerifyCode extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // response.getWriter().append("Served at: ").append(request.getContextPath()); //创建对象 TverifyCode vc = new TverifyCode(); //获取图片对象 BufferedImage bi = vc.getImage(); //获得图片的文本内容 String text = vc.getText(); // 将系统生成的文本内容保存到session中 request.getSession().setAttribute("text", text); //向浏览器输出图片 TverifyCode.output(bi, response.getOutputStream()); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
（2）TverifyCode.java
package wx.VerifyCode; import java.awt.BasicStroke; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; import java.util.Random; import javax.imageio.ImageIO; public class TverifyCode { private int w = 70; private int h = 35; private Random r = new Random(); // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"} private String[] fontNames = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"}; // 可选字符 private String codes = "0123456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ"; // 背景色 private Color bgColor = new Color(255, 255, 255); // 验证码上的文本 private String text ; // 生成随机的颜色 private Color randomColor() { int red = r.nextInt(150); int green = r.nextInt(150); int blue = r.nextInt(150); return new Color(red, green, blue); } // 生成随机的字体 private Font randomFont() { int index = r.nextInt(fontNames.length); String fontName = fontNames[index];//生成随机的字体名称 int style = r.nextInt(4);//生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体) int size = r.nextInt(5) + 24; //生成随机字号, 24 ~ 28 return new Font(fontName, style, size); } // 画干扰线 private void drawLine(BufferedImage image) { int num = 3;//一共画3条 Graphics2D g2 = (Graphics2D)image.getGraphics(); for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值 int x1 = r.nextInt(w); int y1 = r.nextInt(h); int x2 = r.nextInt(w); int y2 = r.nextInt(h); g2.setStroke(new BasicStroke(1.5F)); g2.setColor(Color.BLUE); //干扰线是蓝色 g2.drawLine(x1, y1, x2, y2);//画线 } } // 随机生成一个字符 private char randomChar() { int index = r.nextInt(codes.length()); return codes.charAt(index); } // 创建BufferedImage private BufferedImage createImage() { BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = (Graphics2D)image.getGraphics(); g2.setColor(this.bgColor); g2.fillRect(0, 0, w, h); return image; } // 调用这个方法得到验证码 public BufferedImage getImage() { BufferedImage image = createImage();//创建图片缓冲区 Graphics2D g2 = (Graphics2D)image.getGraphics();//得到绘制环境 StringBuilder sb = new StringBuilder();//用来装载生成的验证码文本 // 向图片中画4个字符 for(int i = 0; i < 4; i++) {//循环四次，每次生成一个字符 String s = randomChar() + "";//随机生成一个字母 sb.append(s); //把字母添加到sb中 float x = i * 1.0F * w / 4; //设置当前字符的x轴坐标 g2.setFont(randomFont()); //设置随机字体 g2.setColor(randomColor()); //设置随机颜色 g2.drawString(s, x, h-5); //画图 } this.text = sb.toString(); //把生成的字符串赋给了this.text drawLine(image); //添加干扰线 return image; } // 返回验证码图片上的文本 public String getText() { return text; } // 保存图片到指定的输出流 public static void output(BufferedImage image, OutputStream out) throws IOException { ImageIO.write(image, "JPEG", out); } }
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标签：.text 指定 sign 对象 tput iter any 绘制 pre
原文地址：https://www.cnblogs.com/jeeskill/p/10280024.html
