Using Spring IOC technology to implement user login authentication mechanism

Using Spring IOC technology to realize the user login authentication mechanism, users login authentication.

First, the User object is injected into the controller using the automatic assembly mode of Spring, and then the username and password entered by the user are matched with the username and password of the qualified legal user in the system.

When the user name and password match successfully, jump to the login success page; When the user name and password do not match, jump to the page where the login failed.

1. Create User object and define the user name and password properties. The code is as follows:

package com.importnew;

public class User {
  private String username;
  private String password;
  
  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;
  }
}

2. Create controller TestUtil, inject User objects and perform login verification. The code is as follows:

package com.importnew;

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

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;

public class TestUtil extends AbstractController{
  
  private User user;

  public User getUser() {
    return user;
  }
  public void setUser(User user) {
    this.user = user;
  }
  @Override 
  protected ModelAndView handleRequestInternal(HttpServletRequest arg0,
      HttpServletResponse arg1) throws Exception {
    String username = arg0.getParameter("username");
    String password = arg0.getParameter("password");
    if(username.equals(user.getUsername()) && password.equals(user.getPassword())){
      return new ModelAndView("yes");
    }else{
      
      return new ModelAndView("Error");
    }
  }
}

3. Assign values to the properties of User objects in the applicationContext.xml configuration file of Spring, and inject the User objects into the controller TestUtil by means of automatic assembly. The code is as follows:

<?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:context="http://www.springframework.org/schema/context"
  xmlns:tx="http://www.springframework.org/schema/tx"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop.xsd">
    
   <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
     <property name="prefix">
       <value>/</value>
     </property>
     <property name="suffix">
       <value>.jsp</value>
     </property>
   </bean>
   
   <bean id="user" class="com.importnew.User" >
     <property name="username">
       <value>admin</value>
     </property>
     <property name="password">
       <value>123</value>
     </property>
   </bean>
   
   <bean autowire="byName" id="testUtil" class="com.importnew.TestUtil" >
     <property name="user">
       <ref bean="user"/>
     </property>
   </bean>
</beans>

4. Configure the automatic loading of applicationContext.xml in the web.xml file. When the project starts, the program will automatically load the information in the configuration file. The code is as follows:

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
 <display-name>Archetype Created Web Application</display-name>
 <servlet>
     <servlet-name>dispatcherServlet</servlet-name>
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <init-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/applicationContext.xml</param-value>
     </init-param>
     <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
     <servlet-name>dispatcherServlet</servlet-name>
     <url-pattern>*.do</url-pattern>
 </servlet-mapping>
 
</web-app>

Remark:

The class AbstractController inherited in TestUtil requires support for the JAR package for spring-web-mvc.

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