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  • springboot开发之实现登录功能

    接上一节。

    开发期间更改模板后使其实时生效,需要进行两步:

    • 在主配置文件中禁用模板缓存:spring.thymeleaf.cache=false。
    • 修改完模板后按ctrl+f9进行重新编译。

    1、首先是login.html:指定我们表单发送的请求

    <!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/4.1.2/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="/" 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="@{/login.html(l='zh_CN')}">中文</a>
                <a class="btn btn-sm" th:href="@{/login.html(l='en_US')}">English</a>
            </form>
        </body>
    
    </html>

    2、在com.gong.springbootcurd.controller下新建LoginController.java

    package com.gong.springbootcurd.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("admin".equals(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","用户或名密码错误");
                return  "login";
            }
    
        }
    }

    说明:这里我们可以使用PostMapping发送Post请求,不必向原来的springmvc那样麻烦。直接模拟账号和密码,如果是admin+123456,则将用户名存放到session中,为了避免重复提交,重定向到/main.html。如果登录失败,则返回错误信息“用户名或密码错误”到登录界面。

    3、配置/main.html跳转到/templates/dashboard.html同时,为了避免没有登录而直接发送请求进入该页面,需要配置一个登录拦截器。

    在com.gong.springbootcurd.component下新建LoginHandlerInceptor.java

    package com.gong.springbootcurd.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("/login.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 {
    
        }
    }

    从session中获取用户名,如果有,则放行,如果没有,将错误信息传给login.html。

    MyMvcConfig.java

    package com.gong.springbootcurd.config;
    
    import com.gong.springbootcurd.component.LoginHandlerInterceptor;
    import com.gong.springbootcurd.component.MyLocaleResolver;
    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.WebMvcConfigurer;
    
    //@EnableWebMvc 接管springmvc
    @Configuration
    public class MyMvcConfig implements WebMvcConfigurer{
        @Override
        public void addViewControllers(ViewControllerRegistry registry) {
            //浏览器发送gong请求会跳转到/templates/success.html页面
            registry.addViewController("gong").setViewName("success");
        }
        //所有的WebMvcConfigurer会一起起作用
        //将组件注册到容器中
        @Bean
        public WebMvcConfigurer webMvcConfigurer() {
            WebMvcConfigurer webMvcConfigurer = new WebMvcConfigurer(){
                public void addViewControllers(ViewControllerRegistry registry) {
                    registry.addViewController("/").setViewName("login");
                    registry.addViewController("/login.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("/login.html","/","/user/login","/asserts/**","/webjars/**");
                }
            };
            return webMvcConfigurer;
        }
    
        @Bean
        public LocaleResolver localeResolver(){
            return new MyLocaleResolver();
        }
    
    }

    4、启动服务器

    首先是直接访问localhost:8080/curd/main.html

    跳转到登录界面,并提示没有权限,我们输入admin+123456:

    重定向的dashboard.html

    dashboard.html就不贴了,太多。

    至此,模拟登录功能基本完成。 

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  • 原文地址:https://www.cnblogs.com/xiximayou/p/12255818.html
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