步骤一：修改 登录页 index.html
原始的：
修改后的：
步骤二：编写一个 LoginController
package cn.ys.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 {
@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)){
//登陆成功
return "dashboard";
}else{
//登陆失败
map.put("msg","用户名密码错误");
return "index";
}
}
}
测试
启动工程，浏览器输入 http://localhost:8080/ ，输入用户名 admin 密码 123456，报错：
原因：
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<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="#{index.tip}">Please sign in</h1>
<label class="sr-only" th:text="#{index.username}">Username</label>
<input type="text" name="username" class="form-control" placeholder="Username" required="" autofocus="">
<label class="sr-only" th:text="#{index.password}">Password</label>
<input type="password" name="password" class="form-control" placeholder="Password" required="">
<div class="checkbox mb-3">
<label>
<input type="checkbox" value="remember-me">[[#{index.remember}]]
</label>
</div>
<button class="btn btn-lg btn-primary btn-block" type="submit" th:text="#{index.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>
再次测试
启动工程，浏览器输入 http://localhost:8080/ ，输入用户名 admin 密码 123456，报错：
原因：没有关闭 模板引擎缓存
spring:
thymeleaf:
cache: false
再次测试
启动工程，浏览器输入 http://localhost:8080/ ，输入用户名 admin 密码 123456，登陆成功：
步骤三：实现密码错误显示效果
修改 index.html
再次测试
启动工程，浏览器输入 http://localhost:8080/ ，输入用户名 admin 密码 111111，登陆失败：
步骤四：解决刷新页面表单重复提交的问题
将 用户数据放入到 域中，使用重定向。
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添加试图映射
修改 LoginController
package cn.ys.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 {
@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)){
//登陆成功，防止表单重复提交，可以重定向到主页
return "redirect:/main.html";
}else{
//登陆失败
map.put("msg","用户名密码错误");
return "index";
}
}
}
再次测试
启动工程，浏览器输入 http://localhost:8080/ ，输入用户名 admin 密码 123456，登陆成功
存在问题：任何浏览器输入 http://localhost:8080/main.html ，都可以进入后台页面
步骤五：拦截器进行登陆检查
将用户放到session 域中
package cn.ys.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 javax.servlet.http.HttpSession;
import java.util.Map;
@Controller
public class LoginController {
@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 "index";
}
}
}
编写拦截器 LoginHandlerInterceptor
package cn.ys.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，在 MyMvcConfig 里面
package cn.ys.config;
import cn.ys.component.LoginHandlerInterceptor;
import cn.ys.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.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
//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");
super.addInterceptors(registry);
}
// 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("index");
registry.addViewController("/index.html").setViewName("index");
registry.addViewController("/main.html").setViewName("dashboard");
}
};
return adapter;
}
@Bean
public LocaleResolver localeResolver(){
return new MyLocaleResolver();
}
}
测试：浏览器直接输入 http://localhost:8080/main.html
修改 dashboard.html 即可
原始的：
修改成：
