Spring+MyBatis 实现登录及验证码功能：

版权声明：未经本人同意，不得私自转载 https://blog.csdn.net/weixin_41866744/article/details/87892677

Spring+MyBatis环境搭建:

1.依赖jar:

2.web.xml配置实现自动加载applicationContext.xml的Spring核心配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>ValidCode</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- 当tomcat加载web.xml时，把spring配置文件信息存放在appication对象
  	   WebApplicationContext容器，时ApplicationContext子接口 -->
  <!-- 设置spring配置文件路径 -->
  <context-param>
	<param-name>contextConfigLocation</param-name>  
	<param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  
  <!-- 加载spring配置文件 -->
  <listener>
  	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  
</web-app>

3.applicationContext.xm编写：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">
	
	<!-- 获取数据源 -->
	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
    	<property name="url" value="jdbc:mysql://localhost:3306/ssm"></property>
    	<property name="username" value="root"></property>
    	<property name="password" value="root"></property>
	</bean>
	
	<!-- spring帮助创建SqlSessionFactory -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="dataSource"></property>
	</bean>
	
	<!--  扫描器,扫描接口,并创建接口对象交由SpringBean管理-->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.tao.mapper"></property>
		<property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
	</bean>
        
</beans>

Spring+MyBatis环境搭建已经完成，接下来写我们的功能开发代码即可:

package com.tao.pojo;

public class Users {
	private int id;
	private String username;
	private String password;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

package com.tao.mapper;

import org.apache.ibatis.annotations.Select;

import com.tao.pojo.Users;

public interface UsersMapper {
	@Select("select * from users where username=#{username} and password=#{password}")
	Users selByUsersPwd(Users users);
}

package com.tao.service;

import com.tao.pojo.Users;

public interface UsersService {
	
	/**
	 * 登录
	 * @param users
	 * @return
	 */
	Users login(Users users);
}

package com.tao.service.impl;

import com.tao.mapper.UsersMapper;
import com.tao.pojo.Users;
import com.tao.service.UsersService;

public class UsersServiceImpl implements UsersService{
	
	private UsersMapper usersMapper;
	public UsersMapper getUsersMapper() {
		return usersMapper;
	}
	public void setUsersMapper(UsersMapper usersMapper) {
		this.usersMapper = usersMapper;
	}

	@Override
	public Users login(Users users) {
		return usersMapper.selByUsersPwd(users);
	}

}

验证码生成类：

package com.tao.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
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;

@WebServlet("/validcode")
public class ValidCodeServlet extends HttpServlet{

	private static final long serialVersionUID = 1L;
	
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//创建一张图片
		//单位:像素
		BufferedImage image =  new BufferedImage(200, 100, BufferedImage.TYPE_INT_RGB);
		
		//透明的玻璃
		//向画板上画内容之前必须先设置画笔.
		Graphics2D gra = image.createGraphics();
		gra.setColor(Color.WHITE);
		
		//从哪个坐标开始填充, 后两个参数,矩形区域
		gra.fillRect(0, 0, 200, 100);
	
		List<Integer> randList = new ArrayList<Integer>();
		Random random =new Random();
		for (int i = 0 ;i<4;i++) {
			randList.add(random.nextInt(10));
		}
		
		//设置字体
		gra.setFont(new Font("宋体",Font.ITALIC|Font.BOLD,40));
		Color[] colors = new Color[]{Color.RED,Color.YELLOW,Color.BLUE,Color.GREEN,Color.PINK,Color.GRAY};
		for (int i = 0; i < randList.size(); i++) {
			gra.setColor(colors[random.nextInt(colors.length)]);
			gra.drawString(randList.get(i)+"", i*40, 70+(random.nextInt(21)-10));
		}
		
		for (int i = 0; i < 2; i++) {
			gra.setColor(colors[random.nextInt(colors.length)]);
			//画横线
			gra.drawLine(0, random.nextInt(101), 200, random.nextInt(101));
		}
		
		ServletOutputStream outputStream = resp.getOutputStream();
		//工具类
		ImageIO.write(image, "jpg", outputStream);
		//把验证码放入到session中
		HttpSession session = req.getSession();
		session.setAttribute("code", ""+randList.get(0)+randList.get(1)+randList.get(2)+randList.get(3));
		
	}

}

登陆类：

package com.tao.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.tao.pojo.Users;
import com.tao.service.UsersService;
import com.tao.service.impl.UsersServiceImpl;

public class LoginServlet extends HttpServlet{

	private static final long serialVersionUID = 1L;
	
	private UsersService usersService;
	
	@Override
	public void init() throws ServletException {
		ApplicationContext ac  = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
		usersService=ac.getBean("usersService",UsersServiceImpl.class);
	}
	
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		String code = req.getParameter("code");	//用户输入的验证码
		String codeSession = req.getSession().getAttribute("code").toString();	//放在session中生成的验证码
		if(codeSession.equals(code)){
			String username = req.getParameter("username");
			String password = req.getParameter("password");
			Users users = new Users();
			users.setPassword(password);
			users.setUsername(username);
			Users user = usersService.login(users);
			if(user!=null){
				resp.sendRedirect("main.jsp");
			}else{
				req.setAttribute("error", "用户名密码不正确");
				req.getRequestDispatcher("index.jsp").forward(req, resp);
			}
		}else{
			req.setAttribute("error", "验证码不正确");
			req.getRequestDispatcher("index.jsp").forward(req, resp);
		}
	}

}

需要导入Jquery.js

页面：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-1.7.2.js"></script>
<script type="text/javascript">
$(function(){
	function flushCode(){
		alert("1");
		$("a").click(function(){
			//浏览器带有缓存功能,不会多次请求相同数据
			$("img").attr("src","validcode?date="+new Date());
			return false;
		});
	}
})	

</script>
</head>
<body>
${error }
<form action="login" method="post">
	<table>
		<tr>
			<td>用户名:<input type="text" name="username"/></td>
		</tr>
		<tr>
			<td>密   码:<input type="password" name="password"/></td>
		</tr>
		<tr>
			<td>验证码:<input type="text" size="1" name="code"/><img src="validcode" width="80" height="40"/><a href="">看不清</a></td>
		</tr>
	</table>
	<input type="submit" value="登录"/><input type="reset" value="重置"/>
	
</body>
</html>

验证码其实就是一个字节流，jquery进入时初始化方法访问验证码生成的servlet，返回字节流到前台显示，每次点击看不清，请求一次src，生成新的验证码。关于页面解析，其实一一次请求，到页面时解析dom，不同标签，客户端会帮我们发相应的请求到后台，去响应不同的静态资源。