工具类：
package com.lhy.web.servlet;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public class VerifyCode {
private int w = 70;//图片长
private int h = 35;//图片宽
private Random r = new Random();//Random类 生成随机数
// 列举验证图片中验证码的字体类型
//{"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"};
// 验证码可选字符
private String codes="23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
// 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 () {
//宽，高，图片的类型
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;
}
// 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);
}
// 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;
}
public static void main(String[] args) throws FileNotFoundException, IOException {
VerifyCode vc = new VerifyCode();//创建VerifyCode类的对象
BufferedImage bi = vc.getImage();//调用getImge()方法获得一个BufferedImage对象
VerifyCode.output(bi, new FileOutputStream("C:/验证码3.jpg"));//调用静态方法output()方法将图片保存在文件输出流中
System.out.println(vc.getText());//在控制台上打印验证码的文本值
}
}
VerifyCodeServlet：
package com.lhy.web.servlet;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class VerifyCodeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/*
* 1. 生成图片
* 2. 保存图片上的文本到session域中
* 3. 把图片响应给客户端
*/
VerifyCode vc = new VerifyCode();
BufferedImage image = vc.getImage();
request.getSession().setAttribute("session_vcode", vc.getText());//保存图片上的文本到session域
VerifyCode.output(image, response.getOutputStream());
}
}
LoginServlet:
package com.lhy.web.servlet;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/*
* 校验验证码
* 1. 从session中获取正确的验证码
* 2. 从表单中获取用户填写的验证码
* 3. 进行比较！
* 4. 如果相同，向下运行，否则保存错误信息到request域，转发到login.jsp
*/
String sessionCode = (String) request.getSession().getAttribute("session_vcode");
String paramCode = request.getParameter("verifyCode");
if(!paramCode.equalsIgnoreCase(sessionCode)) {
request.setAttribute("msg", "验证码错误！");
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
/*
* 1. 获取表单数据
*/
// 处理中文问题
request.setCharacterEncoding("utf-8");
// 获取
String username = request.getParameter("username");
String password = request.getParameter("password");
/*
* 2. 校验用户名和密码是否正确
*/
if("itcast".equalsIgnoreCase(username)) {//登录成功
/*
* 附加项：把用户名保存到cookie中，发送给客户端浏览器
* 当再次打开login.jsp时，login.jsp中会读取request中的cookie，把它显示到用户名文本框中
*/
Cookie cookie = new Cookie("uname", username);//创建Cookie
cookie.setMaxAge(60*60*24);//设置cookie命长为1天
response.addCookie(cookie);//保存cookie
/*
* 3. 如果成功
* > 保存用户信息到session中
* > 重定向到succ1.jsp
*/
HttpSession session = request.getSession();//获取session
session.setAttribute("username", username);//向session域中保存用户名
response.sendRedirect("/Test/succ1.jsp");
} else {//登录失败
/*
* 4. 如果失败
* > 保存错误信息到request域中
* > 转发到login.jsp
*/
request.setAttribute("msg", "用户名或密码错误!");
RequestDispatcher qr = request.getRequestDispatcher("/login.jsp");//得到转发器
qr.forward(request, response);//转发
}
}
}
login.jsp:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>My JSP 'login.jsp' starting page <%-- 本页面提供登录表单，还要显示错误信息 --%>登录
<% /* 读取名为uname的Cookie! 如果为空显示："" 如果不为空显示：Cookie的值 */ String uname = ""; Cookie[] cs = request.getCookies();//获取请求中所有的cookie if(cs != null) {// 如果存在cookie for(Cookie c : cs) {//循环遍历所有的cookie if("uname".equals(c.getName())) {//查找名为uname的cookie uname = c.getValue();//获取这个cookie的值，给uname这个变量 } } } %> <% String message = ""; String msg = (String)request.getAttribute("msg");//获取request域中的名为msg的属性 if(msg != null) { message = msg; } %> <%=message %>
loginsuccess：
succ1
<% String username = (String)session.getAttribute("username"); if(username == null) { /* 1. 向request域中保存错误信息，转发到login.jsp */ request.setAttribute("msg", "您还没有登录!请先登录!"); request.getRequestDispatcher("/login.jsp").forward(request, response); return; } %>
欢迎欢迎，热烈欢迎，欢迎<%=username %>领导指导工作！