• 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();
    }

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