Spring Mvc拦截器的实现与登录案例

拦截器的基本配置

1.自定义拦截器实现HandlerInterceptor 接口

public class PermissionInterceptor implements HandlerInterceptor {
	private final static Log log= LogFactory.getLog(PermissionInterceptor.class);
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		log.info("preHandle");
		return true;
	}
	
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
		log.info("postHandle");
	}
	
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
		log.info("afterCompletion");
	}
}

2.配置spring mvc文件

/** 所有路径及里面的子路径

/* 当前路径下的所有路径,不含子文件

/  项目根目录的请求

  <mvc:interceptors>
    <!-- 拦截所有 -->
    <mvc:interceptor>
        <!-- 拦截指定的请求url -->
        <mvc:mapping path="/user/**"/>
        <bean class="cn.ybzy.common.interceptor.Permissioninterceptor"/>
    </mvc:interceptor>
    </mvc:interceptors>

3.编写登录方法

   @RequestMapping(value = "login",method = RequestMethod.GET)
    @ResponseBody
    public String login(String name,String pwd){
        System.out.println("name:"+name+"------"+"pwd:"+pwd);
        return "Hello World!";
    }

4.断点验证


5.拦截器执行流程
preHandle在请求之前调用

执行业务

postHandle在请求后调用

afterCompletion在请求结束调用

简单案例实现

1.用户登录过程实现

    @RequestMapping(value = "login",method = RequestMethod.GET)
    @ResponseBody
    public String login(String username, String password, HttpSession session, ServletResponse response){
        //向浏览器写入cookies
        Cookie ck = new Cookie("sso-cookies",session.getId());
        ck.setDomain("localhost");
        ck.setPath("/");
        ck.setHttpOnly(true);
        ck.setMaxAge(60 * 30);
        HttpServletResponse resp=(HttpServletResponse)response;
        resp.addCookie(ck);
    
    	//构造一个成功登录的用户信息
        JSONObject object = new JSONObject();
        object.put("name",username);
        object.put("pwd",password);
    
        //向redis写入数据
        Jedis jedis = new Jedis("localhost");
        jedis.setex(session.getId(),60*30,object.toJSONString());
        return "Hello World!";
    }

2.拦截业务实现

@Slf4j
public class PermissionInterceptor implements HandlerInterceptor {
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		log.info("preHandle");
		//请求Controller中的方法名
		HandlerMethod handlerMethod = (HandlerMethod)handler;
		
		//请求的方法名
		String methodName = handlerMethod.getMethod().getName();
		//请求方法所在类的类名
		String className = handlerMethod.getBean().getClass().getSimpleName();
		
		//解析请求参数
		HashMap<Object, Object> hashMap = new HashMap<>();
		Map paramMap = request.getParameterMap();
		Iterator it = paramMap.entrySet().iterator();
		while (it.hasNext()){
			Map.Entry entry = (Map.Entry)it.next();
			String mapKey = (String)entry.getKey();
			
			String mapValue = StringUtils.EMPTY;
			
			// entry.getValue()里面的value返回的是一个String[]
			Object obj = entry.getValue();
			if(obj instanceof String[]){
				String[] strs = (String[])obj;
				mapValue = Arrays.toString(strs);
			}
			hashMap.put(mapKey,mapValue);
		}
		log.info("request parameters : {}",hashMap);
		
		if(StringUtils.equals(className,"UserController") && StringUtils.equals(methodName,"login")){
			log.info("权限拦截器拦截到请求,className:{},methodName:{}",className,methodName);
			return true;
		}
		
		log.info("权限拦截器拦截到请求,className:{},methodName:{},param:{}",className,methodName, hashMap.toString());
		
		
		User user = null;
		
		//获取登录时写入的cookies
		String loginToken=null;
		Cookie[] cookies = request.getCookies();
		if(cookies != null){
			for(Cookie cookie : cookies){
				if(StringUtils.equals(cookie.getName(),"sso-cookies")){
					loginToken= cookie.getValue();
				}
			}
		}
		
		//从redis中取登录的用户信息
		if(StringUtils.isNotEmpty(loginToken)){
			Jedis jedis = new Jedis("localhost");
			String userJson = jedis.get(loginToken);
			user =JSONObject.parseObject(userJson,User.class);
		}
		
		//假设该登录用户的角色 admin
		String userRole="admin";
		
		if(user == null || (!StringUtils.equals(userRole, "admin"))){
			// 设置编码/返回值类型
			response.setCharacterEncoding("UTF-8");
			response.setContentType("application/json;charset=UTF-8");
			
			PrintWriter out = response.getWriter();

			if(user == null){
				out.print("拦截器拦截,未登录!");
			}else{
				out.print("拦截器拦截,无权限!");
			}
			out.flush();
			out.close();
			
			//返回false.不执行controller里的方法
			return false;
		}
		return true;
	}
	
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
		log.info("postHandle");
	}
	
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
		log.info("afterCompletion");
	}
}

3.访问登录方法

1.request参数的map，里面的value返回的是一个String[]

2.cookies写入浏览器

3.用户信息存入redis

4.获取登录用户信息:

   @RequestMapping(value = "getUserInfo",method = RequestMethod.GET)
    @ResponseBody
    public String getUserInfo(String username, String password, HttpServletRequest request){
    //获取cookie
        String loginToken=null;
        Cookie[] cookies = request.getCookies();
        if(cookies != null){
            for(Cookie cookie : cookies){
                if(StringUtils.equals(cookie.getName(),"sso-cookies")){
                    loginToken= cookie.getValue();
                }
            }
        }
        
        //redis中取用户信息
        if(StringUtils.isNotEmpty(loginToken)){
            Jedis jedis = new Jedis("localhost");
            String userJson = jedis.get(loginToken);
            return  JSONObject.parseObject(userJson).toJSONString();
        }
        return null;
    }

1.已登录且String userRole="admin";

2.未登录

3.已登录且String userRole="product";

本文地址：https://blog.csdn.net/qq_38628046/article/details/107348884