SpringMVC 实现用户登录实例代码

Z时代
2024-01-10
分类：IT

SpringMVC的一个登陆小案例

准备工作

创建一个Dynamic Web Project（本人是Eclipse）

添加相关的jar包，构建路径

创建springMVC-servlet.xml，及完善web.xml

创建代码逻辑

目录结构如下

对于新手而言，有一个项目的完整的目录结构是多么幸福的一件事啊。

目录结构

个人建议：注意其中的springMVC-servlet.xml的位置。以及源代码包的名称。

代码实战

首先是大管家，web.xml:


<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
  id="WebApp_ID" version="3.1">
  <display-name>SpringTest</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>springMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>springMVC</servlet-name>
    <url-pattern>*.spring</url-pattern>
  </servlet-mapping>
</web-app>

然后是小管家springMVC-servlet.xml:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd

http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd

http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">

<context:component-scan base-package="controller"></context:component-scan>

</beans>

再就是一个登陆界面了，login.jsp:


<%@ 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>登陆界面</title>
</head>
<body>
  <form action="login.spring" method="post">
    username:<input type="text" name="username"><br /> Password:<input
      type="password" name="password"><br /> <input type="submit"
      value="登陆">
  </form>
</body>
</html>


package controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller // @Controller 代表本Java类是controller控制层
public class Login {
  /**
   * @RequestParam注解的作用是：根据参数名从URL中取得参数值
   * @param username
   *      用户名，一定要对应着表单的name才行
   * @param password
   *      用户密码，也应该对应表单的数据项
   * @param model
   *      一个域对象，可用于存储数据值
   * @return
   */
  @RequestMapping("/login") // @RequestMapping 注解可以用指定的URL路径访问本控制层
  public String login(@RequestParam("username") String username, @RequestParam("password") String password,
      Model model) {
    if (username.equals("admin") && password.equals("admin")) {
      model.addAttribute("username", username);
      return "ok.jsp";
    } else {
      model.addAttribute("username", username);
      return "no.jsp";
    }
  }
}

最后就是ok.jsp和no.jsp了：


<%@ 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>
</head>
<body>
<font color="green">${username } </font>欢迎你！
</body>
</html>
<%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
  <font color="red">Sorry</font>，没有${username }这个用户!
  <br />
  <a href="login.jsp" rel="external nofollow" >重试一下！</a>
</body>
</html>