SpringMVC创建拦截器配置拦截器

太过爱你忘了你带给我的痛 2023-09-24 19:56 6阅读 0赞

**创建[拦截器][Link 1]，并且配置拦截器，一共只有三步骤，并且非常简单**

1.  创建自定义的拦截器
2.  注入到spring容器中
3.  配置拦截器拦截的路径

# 1.创建自定义的拦截器 #

创建一个类，实现[HandlerInterceptor][]接口，它就是自定义的拦截器类

/*拦截器顾名思义，就是用来拦截Controller的请求的*/
    public class LoginInterceptor implements HandlerInterceptor {
    	
    	/*在Controller之前执行*/
    	@Override
    	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
    		
    		System.out.println("LoginInterceptor --- >  preHandle");
    		
    		//false : 拦截Controller，Controller将不执行
    		//true  : 放行，继续执行Controller
    		return true; 
    	}
    	
    	//在Controller之后执行
    	@Override
    	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
    			throws Exception {
    		
    		System.out.println("LoginInterceptor --- >  postHandle");
    	}
     
    	//渲染视图以后执行
    	@Override
    	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
    			throws Exception {
    		System.out.println("LoginInterceptor --- >  afterCompletion");
    	}
     
    }

有时候大家看到别人创建拦截器类是继承了HandlerInterceptorAdapter也别感到奇怪

因为HandlerInterceptorAdapter类也作为子类实现了HandlerInterceptor接口

所以，自己创建拦截器类继承HandlerInterceptorAdapter

或者实现HandlerInterceptor接口是一模一样的

# 2.注入到spring容器中 #

这一步骤非常简单，只需要使用注解，或者在xml配置文件中进行配置即可

# 3.配置拦截器拦截的路径 #

3.1 只配置拦截器，不配置拦截路径

<mvc:interceptors>
            <ref bean="loginInterceptor" />
    </mvc:interceptors>

3.2 我们推荐使用下列方式配置拦截路径，它和上边的配置大同小异，就只是多了拦截路径的配置而已

<mvc:interceptors>
    		<mvc:interceptor>
    			
    			<mvc:mapping path="/**" />
    			
    			
    			<mvc:exclude-mapping path="/show-login-page" />
    			<mvc:exclude-mapping path="/find/*" />
    			
    			
    			<ref bean="loginInterceptor" />
    		</mvc:interceptor>
    	</mvc:interceptors>

# **4.测试效果** #

首先测试不拦截的路径，发现控制台没有任何输出

![0c22f7d4bd5142dca07b9a55767cde6f.png][]

然后再测试拦截路径，可以看到拦截器执行了

![b24df0c51d5a42d78682e17adfb3f40c.png][]

查看控制台，可以看到，拦截器生效了

![ddb7ff81b16549749bed34ea7f4bbb72.png][]

最后，为了方便大家阅读学习，删除所有的注释，附上完整的代码和逻辑

**Java类 ，自定义拦截器类**

public class LoginInterceptor implements HandlerInterceptor {
     
    	@Override
    	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
    		
    		System.out.println("LoginInterceptor --- >  preHandle");
     
    		return true; 
    	}
     
    	@Override
    	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
    			throws Exception {
    		
    		System.out.println("LoginInterceptor --- >  postHandle");
    	}
     
    	
    	@Override
    	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
    			throws Exception {
    		System.out.println("LoginInterceptor --- >  afterCompletion");
    	}
     
    }

**配置文件，进行IOC配置和拦截器配置**

[Link 1]: https://so.csdn.net/so/search?q=%E6%8B%A6%E6%88%AA%E5%99%A8&spm=1001.2101.3001.7020
[HandlerInterceptor]: https://so.csdn.net/so/search?q=HandlerInterceptor&spm=1001.2101.3001.7020
[0c22f7d4bd5142dca07b9a55767cde6f.png]: https://img-blog.csdnimg.cn/0c22f7d4bd5142dca07b9a55767cde6f.png
[b24df0c51d5a42d78682e17adfb3f40c.png]: https://img-blog.csdnimg.cn/b24df0c51d5a42d78682e17adfb3f40c.png
[ddb7ff81b16549749bed34ea7f4bbb72.png]: https://img-blog.csdnimg.cn/ddb7ff81b16549749bed34ea7f4bbb72.png