SpringBoot简单实现登录功能

登陆

开发期间模板引擎页面修改以后,要实时生效

1)、禁用模板引擎的缓存

# 禁用缓存
spring.thymeleaf.cache=false 

2)、页面修改完成以后ctrl+f9:重新编译;

登陆错误消息的显示

<p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>

login.html

<!DOCTYPE html>
<html lang="en"  xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        <meta name="description" content="">
        <meta name="author" content="">
        <title>Signin Template for Bootstrap</title>
        <!-- Bootstrap core CSS -->
        <link href="asserts/css/bootstrap.min.css" th:href="@{/webjars/bootstrap/4.0.0/css/bootstrap.css}" rel="stylesheet">
        <!-- Custom styles for this template -->
        <link href="asserts/css/signin.css" th:href="@{/asserts/css/signin.css}" rel="stylesheet">
    </head>
    <body class="text-center">
        <form class="form-signin" action="dashboard.html" th:action="@{/user/login}" method="post">
            <img class="mb-4" th:src="@{/asserts/img/bootstrap-solid.svg}" src="asserts/img/bootstrap-solid.svg" alt="" width="72" height="72">
            <h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1>
            <!--判断-->
            <p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>
            <label class="sr-only" th:text="#{login.username}">Username</label>
            <input type="text"  name="username" class="form-control" placeholder="Username" th:placeholder="#{login.username}" required="" autofocus="">
            <label class="sr-only" th:text="#{login.password}">Password</label>
            <input type="password" name="password" class="form-control" placeholder="Password" th:placeholder="#{login.password}" required="">
            <div class="checkbox mb-3">
                <label>
                      <input type="checkbox" value="remember-me"/> [[#{login.remember}]]
                </label>
            </div>
            <button class="btn btn-lg btn-primary btn-block" type="submit" th:text="#{login.btn}">Sign in</button>
            <p class="mt-5 mb-3 text-muted">© 2017-2018</p>
            <a class="btn btn-sm" th:href="@{/index.html(l='zh_CN')}">中文</a>
            <a class="btn btn-sm" th:href="@{/index.html(l='en_US')}">English</a>
        </form>
    </body>

</html>

4)、Controller层

  LoginController:

package com.atguigu.springboot.controller;

import org.springframework.stereotype.Controller;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpSession;
import java.util.Map;

@Controller
public class LoginController {

//    @DeleteMapping
//    @PutMapping
//    @GetMapping

    //@RequestMapping(value = "/user/login",method = RequestMethod.POST)
    @PostMapping(value = "/user/login")
    public String login(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        Map<String,Object> map, HttpSession session){
        if(!StringUtils.isEmpty(username) && "123456".equals(password)){
            //登陆成功,防止表单重复提交,可以重定向到主页
            session.setAttribute("loginUser",username);
            return "redirect:/main.html";
        }else{
            //登陆失败

            map.put("msg","用户名密码错误");
            return  "login";
        }

    }
}

4)、拦截器进行登陆检查

拦截器

package com.atguigu.springboot.component;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

/**
 * 登陆检查,
 */
public class LoginHandlerInterceptor implements HandlerInterceptor {
    //目标方法执行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object user = request.getSession().getAttribute("loginUser");
        if(user == null){
            //未登陆,返回登陆页面
            request.setAttribute("msg","没有权限请先登陆");
            request.getRequestDispatcher("/index.html").forward(request,response);
            return false;
        }else{
            //已登陆,放行请求
            return true;
        }

    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }

}

注册拦截器:
package com.atguigu.springboot.config;

import com.atguigu.springboot.component.LoginHandlerInterceptor;
import com.atguigu.springboot.component.MyLocaleResolver;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
//@EnableWebMvc //不要接管SpringMVC
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {



@Override
public void addViewControllers(ViewControllerRegistry registry) {
// super.addViewControllers(registry);
//浏览器发送 /atguigu 请求来到 success
registry.addViewController("/atguigu").setViewName("success");
}

//所有的WebMvcConfigurerAdapter组件都会一起起作用
@Bean //将组件注册在容器
public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("login");
registry.addViewController("/index.html").setViewName("login");
registry.addViewController("/main.html").setViewName("dashboard");
}

//注册拦截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//super.addInterceptors(registry);
//静态资源; *.css , *.js
//SpringBoot已经做好了静态资源映射
registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
.excludePathPatterns("/index.html","/","/user/login");
}
};
return adapter;
}

@Bean
public LocaleResolver localeResolver(){

return new MyLocaleResolver();
}

}
原文地址:https://www.cnblogs.com/zqLoveSym/p/10570557.html