20 Web开发实战--登录&拦截器

1 更改页面,实时生效

a): 禁用模板引擎缓存
	spring.thymeleaf.cache=false

b): 更改页面完成后,按 Ctrl + F9 进行编译

2 登录

package com.gp6.springboot18.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 {

    //@RequestMapping(value = "/user/login",method = RequestMethod.POST)与@PostMapping(value = "/user/login")等效
    @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)) {
            //登录成功，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 {
            //登录失败
            map.put("msg", "用户名密码错误");
            return "login";
        }
    }
}

3 自定义拦截器

3.1 MyHandlerInterceptor

package com.gp6.springboot18.config;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 自定义拦截器
 */
public class MyHandlerInterceptor implements HandlerInterceptor {
    //目标方法执行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 判断session是否包含用户名
        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 {

    }
}

3.2 将自定义拦截器注入容器

package com.gp6.springboot18.config;

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.WebMvcConfigurer;

@Configuration
public class MyConfig implements WebMvcConfigurer {

    /*
        所有的WebMvcConfigurer组件会一起生效
    */
    @Override
    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) {
        /*
            SpringBoot已配置静态资源映射,编写拦截器时,无需考虑静态资源
        */
        registry.addInterceptor(new MyHandlerInterceptor()).
                // 拦截的请求(/** : 所有)
                addPathPatterns("/**")

                // 放行的请求
                .excludePathPatterns("/login.html","/","/user/login");
    }

    /*
        将自定义的区域信息解析器注入到容器中
    */
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();
    }
}