java实现简单的动态验证码
在服务端实现简单的动态验证码
不废话，直接见代码
1、首先：CheckCodeServlet.java ，实现动态画图功能
import javax.imageio.ImageIO;
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 java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
/**
* 实现简单的验证码
*/
@WebServlet("/checkcode")
public class CheckCodeServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 100;
int height = 50;
//1.创建一对象，在内存中图片(验证码图片对象)
BufferedImage image = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
//2.美化图片
//2.1 填充背景色
Graphics g = image.getGraphics();//画笔对象
g.setColor(Color.PINK);//设置画笔颜色
g.fillRect(0,0,width,height);
//2.2画边框
g.setColor(Color.BLUE);
g.drawRect(0,0,width - 1,height - 1);
String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
//生成随机角标
Random ran = new Random();
for (int i = 1; i <= 4; i++) {
int index = ran.nextInt(str.length());
//获取字符
char ch = str.charAt(index);//随机字符
//2.3写验证码
g.drawString(ch+"",width/5*i,height/2);
}
//2.4画干扰线
g.setColor(Color.GREEN);
//随机生成坐标点
for (int i = 0; i < 10; i++) {
int x1 = ran.nextInt(width);
int x2 = ran.nextInt(width);
int y1 = ran.nextInt(height);
int y2 = ran.nextInt(height);
g.drawLine(x1,y1,x2,y2);
}
//3.将图片输出到页面展示
ImageIO.write(image,"jpg",response.getOutputStream());
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
2、index.html 页面的实现
<%--
Created by IntelliJ IDEA.
User: huangshun
Date: 3/2/19
Time: 1:51 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
$Title$
二维码的简单实现
换一张
二 , 还可以通过session 在服务器端存储生成的验证码与客户端提交的验证码进行校验,这里链接数据库的操作就不进行了,简单使用request 和session 域对象
1)CheckCodeServlet.java
package ImgCode;
import javax.imageio.ImageIO;
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 java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 100;
int height = 50;
//1.创建一对象，在内存中图片(验证码图片对象)
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
//2.美化图片
//2.1 填充背景色
Graphics g = image.getGraphics();//画笔对象
g.setColor(Color.PINK);//设置画笔颜色
g.fillRect(0,0,width,height);
//2.2画边框
g.setColor(Color.BLUE);
g.drawRect(0,0,width - 1,height - 1);
String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
//生成随机角标
Random ran = new Random();
StringBuilder sb = new StringBuilder();
for (int i = 1; i <= 4; i++) {
int index = ran.nextInt(str.length());
//获取字符
char ch = str.charAt(index);//随机字符
sb.append(ch);
//2.3写验证码
g.drawString(ch+"",width/5*i,height/2);
}
String checkCode_session = sb.toString();
//将验证码存入session
request.getSession().setAttribute("checkCode_session",checkCode_session);
//2.4画干扰线
g.setColor(Color.GREEN);
//随机生成坐标点
for (int i = 0; i < 10; i++) {
int x1 = ran.nextInt(width);
int x2 = ran.nextInt(width);
int y1 = ran.nextInt(height);
int y2 = ran.nextInt(height);
g.drawLine(x1,y1,x2,y2);
}
//3.将图片输出到页面展示
ImageIO.write(image,"jpg",response.getOutputStream());
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
2)LoginServlet.java
package ImgCode;
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 javax.servlet.http.HttpSession;
import java.io.IOException;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
String check_code = request.getParameter("check_code");
System.out.println("username="+username+"--password="+password+"--check_code="+check_code);
// 1 先取出 session 里面的 验证码
HttpSession session = request.getSession();
String web_check_code = (String)session.getAttribute("checkCode_session");
session.removeAttribute("web_check_code");// 清除服务器端session
if(web_check_code!=null && web_check_code.equalsIgnoreCase(check_code)){
// 验证码相等 验证用户名
if("admin".equals(username) && "admin".equals(password)){
System.out.println("登录成功");
//response.getWriter().write("登录成功
");
session.setAttribute("username",username);
response.sendRedirect(this.getServletContext().getContextPath()+"/success.jsp");//重定向
System.out.println(this.getServletContext().getContextPath()+"/success.jsp");
}else{
request.setAttribute("login_msg","用户名或密码错误,请重试");
request.getRequestDispatcher("/index.jsp").forward(request,response);
System.out.println("用户名或者密码错误");
}
}else{
request.setAttribute("login_msg","验证码错误,请重试");
request.getRequestDispatcher("/index.jsp").forward(request,response);
System.out.println("验证码错误");
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
3)success.jsp
<%--
Created by IntelliJ IDEA.
User: huangshun
Date: 3/4/19
Time: 8:55 AM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
$Title$
<%
HttpSession session1 = request.getSession();
String username = (String)session1.getAttribute("username");
%>
欢迎你:<%= username%>
4)index.jsp
<%--
Created by IntelliJ IDEA.
User: huangshun
Date: 3/4/19
Time: 8:55 AM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
$Title$
路径的话.可能需要自己配置下