springMVC自定义拦截器的执行顺序即底层原理实现

springMVC自定义拦截器的执行顺序即底层原理实现

首先自定义2个拦截器MyHandlerInterceptor1和MyHandlerInterceptor2

MyHandlerInterceptor1.java

//拦截器
public class MyHandlerInterceptor1 implements HandlerInterceptor {

    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyHandlerInterceptor1 preHandle handler = "+handler);
        return false;
    }

    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyHandlerInterceptor1 postHandle handler = "+handler+ " modelAndView = "+ modelAndView);
    }

    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyHandlerInterceptor1 afterCompletion handler = "+handler+" ex = "+ex);
    }
}

MyHandlerInterceptor2.java

//拦截器
public class MyHandlerInterceptor2 implements HandlerInterceptor {

    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyHandlerInterceptor2 preHandle handler = "+handler);
        return false;
    }

    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyHandlerInterceptor2 postHandle handler = "+handler+ " modelAndView = "+ modelAndView);
    }

    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyHandlerInterceptor2 afterCompletion handler = "+handler+" ex = "+ex);
    }
}

在dispatcher-servlet.xml配置文件中配置拦截器

两个自定义的拦截器的执行情况

关于拦截器放行的问题
第一种情况：MyHandlerInterceptor1 放行 MyHandlerInterceptor2 放行
MyHandlerInterceptor1 preHandle   return true
MyHandlerInterceptor2 preHandle   return true
MyHandlerInterceptor2 postHandle
MyHandlerInterceptor1 postHandle
MyHandlerInterceptor2 afterCompletion
MyHandlerInterceptor1 afterCompletion
第二种情况：MyHandlerInterceptor1 放行 MyHandlerInterceptor2 不放行
MyHandlerInterceptor1 preHandle  return true
MyHandlerInterceptor2 preHandle  return false
MyHandlerInterceptor1 afterCompletion
第三种情况：MyHandlerInterceptor1 不放行 MyHandlerInterceptor2 不放行
MyHandlerInterceptor1 preHandle  return false

对于第二种情况的底层代码解析

为什么会执行MyHandlerInterceptor1 afterCompletion

 

 所以会出现情况二的情况

不足之处敬请谅解！！！