35.SpringBoot学习笔记–CRUD实验–登录与拦截器
开发技巧
开发期间修改模板引擎页面后，要求其实时生效
1、在 application.properties 中禁用模板引擎的缓存
#禁用thymeleaf的缓存
spring.thymeleaf.cache=false
2、页面修改完成以后 CTRL + F9，重新编译。
实现登录功能
templates\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" src="asserts/img/bootstrap-solid.svg" th: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>
<!-- 登录错误消息的显示 -->
<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>
demo.yangxu.springboot.controller.LoginController
package demo.yangxu.springboot.controller;
import org.springframework.stereotype.Controller;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import java.util.Map;
@Controller
public class LoginController {
//@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){
if(!StringUtils.isEmpty(username) && "123456".equals(password)){
//success 防止表单重复提交，可以使用重定向
return "redirect:/main.html";
}else {
//fail
map.put("msg","登录失败，也许是用户名密码错误");
return "login";
}
}
}
demo.yangxu.springboot.config.MyMvcConfig
package demo.yangxu.springboot.config;
import demo.yangxu.springboot.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.*;
//使用WebMvcConfigurer扩展SpringMVC的功能
//@EnableWebMvc
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
//浏览器发送 /yangxu 请求来到 success
registry.addViewController("/yangxu").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");
}
};
return adapter;
}
@Bean
public LocaleResolver localeResolver(){
return new MyLocaleResolver();
}
}
将 dashboard.html 中的 Company name 显示为登录后的用户名
修改前：
<a class="navbar-brand col-sm-3 col-md-2 mr-0" href="http://getbootstrap.com/docs/4.0/examples/dashboard/#">Company name</a>
修改后：
<a class="navbar-brand col-sm-3 col-md-2 mr-0" href="http://getbootstrap.com/docs/4.0/examples/dashboard/#">[[${session.loginUser}]]</a>
参考：
7.1 Simple conditionals: “if” and “unless”
实现拦截器功能
demo.yangxu.springboot.component.LoginHandlerInterceptor
package demo.yangxu.springboot.component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//使用拦截器进行登录检查
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){
//未登录，返回登录页面
request.setAttribute("msg","没有权限，请先登录");
request.getRequestDispatcher("/index.html").forward(request,response);
return false;
}else {
//已登录，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 {
}
}
demo.yangxu.springboot.config.MyMvcConfig
package demo.yangxu.springboot.config;
import demo.yangxu.springboot.component.LoginHandlerInterceptor;
import demo.yangxu.springboot.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.*;
//使用WebMvcConfigurer扩展SpringMVC的功能
//@EnableWebMvc
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
@Override
public void addViewControllers(ViewControllerRegistry registry) {
//浏览器发送 /yangxu 请求来到 success
registry.addViewController("/yangxu").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() {
//注册拦截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//静态资源: *.css , *.js
//spring boot 2.x依赖spring 5.x版本
//静态资源也会执行自定义的拦截器
registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
.excludePathPatterns("/index.html","/","/user/login","/asserts/**","/webjars/**");
}
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("login");
registry.addViewController("/index.html").setViewName("login");
registry.addViewController("/main.html").setViewName("dashboard");
}
};
return adapter;
}
@Bean
public LocaleResolver localeResolver(){
return new MyLocaleResolver();
}
}
