1、為登入頁面的form表單,新增th:action進入controller

<form class="form-signin" th:action="@{/user/login}">

2、input標籤新增“name”屬性

<input type="text" name="username" class="form-control" th:placeholder="#{login.username}" required="" autofocus="">
<input type="password" name="password" class="form-control" th:placeholder="#{login.password}" required="">
 

3、進入controller實現具體的業務程式碼

新建controller

@Controller
public class LoginController {
    @RequestMapping("/user/login")
    public String login(
            @RequestParam("username")String username,
            @RequestParam("password")String password,
            Model model,
            HttpSession session){
        //具體業務：
        if (!StringUtils.isEmpty(username) && "123456".equals(password)){
            System.out.println(username+":"+password);
            session.setAttribute("loginUser",username);
            //重定向
            return "redirect:/main.html";
        }else {
            model.addAttribute("msg","使用者名稱或密碼錯誤");
            return "index";
        }
    }
}
 

如果密碼錯誤頁面顯示錯誤資訊：

<!--th:if thymeleaf模板語法，進行條件判斷-->
<p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>

img.png

• @RequestParam：獲取登入頁面的username和password引數
• Model：進行資料的回顯
• HttpSession：用於設定session，用於後續攔截器的判斷條件

4、在MyMvcConfig進行地址對映

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
        registry.addViewController("/main.html").setViewName("dashboard");
    }
}
 

對映前uri：
http://localhost:8080/user/login?username=123&password=123456
對映後uri:
http://localhost:8080/main.html

5、攔截器設定

建立LoginHandlerInterceptor實現HandlerInterceptor介面
重寫方法：

• public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {}
• public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {}
• public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {}

public class LoginHandlerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //登入成功之後。應該有使用者的session
        Object loginUser = request.getSession().getAttribute("loginUser");
        //沒有登入
        if (loginUser==null){
            request.setAttribute("msg","請先登入");
            //返回主頁，轉發request和response
            request.getRequestDispatcher("/index.html").forward(request,response);
            return false;
        }else {
            return true;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

6、在MyMvcConfig中配置攔截器

public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
        registry.addViewController("/main.html").setViewName("dashboard");
    }

    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();
    }

    //配置攔截器
    public void addInterceptors(InterceptorRegistry registry){
        registry.addInterceptor(new LoginHandlerInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/index.html",
                        "/",
                        "/user/login",
                        "/css/**",
                        "/js/**",
                        "/img/**");
    }
}

如果沒有登入提示使用者登入
img_1.png