SpringMVC的登录拦截器Interceptor+全局异常处理

布满荆棘的人生 2022-04-23 23:54 330阅读 0赞

SpringMVC的拦截器

**1.在spirngmvc.xml的配置文件中添加配置：**

<mvc:interceptors>
              <mvc:interceptor>
                <mvc:mapping path="/**"/>
                <mvc:exclude-mapping path="/user/login"/>
                <mvc:exclude-mapping path="/user/logout"/>
                <mvc:exclude-mapping path="/gotoLogin"/>
                <mvc:exclude-mapping path="/static/**"/>
                <bean class="com.etoak.interceptor.LoginInterceptor"></bean>
              </mvc:interceptor>
           </mvc:interceptors>

**2.编写拦截器Interceptor，Interceptor要实现org.springframework.web.servlet.HandlerInterceptor;**

package com.etoak.interceptor;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import com.etoak.bean.User;
    
    import lombok.extern.slf4j.Slf4j;
    @Slf4j
    public class LoginInterceptor implements HandlerInterceptor {
    
    	@Override
    	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
    			throws Exception {
    		log.info("Login Interceptor");
    		HttpSession session=request.getSession();
    		User user=(User)session.getAttribute("user");
    		if(user==null){
    			String contextPath=request.getContextPath();
    			response.sendRedirect(contextPath+"/gotoLogin");
    			return false;
    		}
    		return true;
    	}
    
    	@Override
    	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
    			ModelAndView modelAndView) throws Exception {
    		// TODO Auto-generated method stub
    		HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    	}
    
    	@Override
    	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
    			throws Exception {
    		// TODO Auto-generated method stub
    		HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    	}
        
    }

**3.全局异常处理**  
**一.首先我们先自己创建一个异常类；这个类继承了RuntimeException**

package com.etoak.common;
    
    import lombok.AllArgsConstructor;
    
    @AllArgsConstructor
    public class LoginException extends RuntimeException {
        //序列化
    	private static final long serialVersionUID= 1L;
        
    	private String message;
    	
    	public String getMessage() {
    		return message;
    	}
    	public void setMessage(String message) {
    		this.message = message;
    	}
       	
    	
    }

**二.然后这个异常在service的实现类中进行抛出；**

@Service
    public class UserServiceImpl implements UserService{
        @Autowired
        UserMapper userMapper;
    	
    	@Override
    	public User queryUser(String username, String password) {
    		// TODO Auto-generated method stub
    		User user=userMapper.queryUser(username, password);
    		if(user==null){
    			throw new LoginException("用户名或密码异常");
    		}
    		return user;
    	}
        
    }

三.创建一个处理全局异常的类；  
顺便提一下@ControllerAdvice的作用  
　通过@ControllerAdvice注解可以将对于控制器的全局配置放在同一个位置。  
　　注解了@Controller的类的方法可以使用@ExceptionHandler、@InitBinder、@ModelAttribute注解到方法上。  
　　@ControllerAdvice注解将作用在所有注解了@RequestMapping的控制器的方法上  
　　@ExceptionHandler：用于全局处理控制器里的异常。  
　　具体的详细解析：[@ControllerAdvice][ControllerAdvice]

@ControllerAdvice
    @Slf4j
    public class GLobalException {
    	@ExceptionHandler(LoginException.class)
         public ModelAndView loginError(LoginException e){
    		log.error("login Exception message:{}",e.getMessage());
    		ModelAndView mv=new ModelAndView();
    		
        	mv.setViewName("login");
        	mv.addObject("error", e.getMessage());    
    		return mv;
        	 
         }
    }

**4.登录的controller层**

@PostMapping("/login")
    	public String login(HttpServletRequest request,@RequestParam String username,
    			@RequestParam String password){
    		User user=userService.queryUser(username, password);
    		log.info("user:{}",user);
    		HttpSession session=request.getSession();
    		session.setAttribute("user", user);
    		return "redirect:/";
    	}

**个人初学者的总结认为拦截器是通过判断Session中是否含有我们所塞进去的attribute的有无情况去进行拦截：**  
controller层进行session.setAttribute()  
Interceptor层进行session.getAttribute()  
目前自己的水平是这样简单是认识的。

[ControllerAdvice]: https://blog.csdn.net/zxfryp909012366/article/details/82955259