对handlerexecutionchain类的深入理解

对handlerexecutionchain类的深入理解

HandlerExecutionChain类比较简单，好理解。

/*

* 处理器执行链由处理器对象和拦截器组成。

*/

public class HandlerExecutionChain {

下面是类的部分属性。

private final Object handler; //处理器对象。

private HandlerInterceptor[] interceptors; //拦截器数组

private List interceptorList; //拦截器列表

/**

* Apply preHandle methods of registered interceptors.

* @return {@code true} if the execution chain should proceed with the

* next interceptor or the handler itself. Else, DispatcherServlet assumes

* that this interceptor has already dealt with the response itself.

* 执行已经注册的拦截的 preHandle()方法。如果返回true,则执行链可以执行下一个拦截器的preHandle()方法或 handler 自身。

* 否则，

*/

boolean applyPreHandle(HttpServletRequest request, HttpServletResponse response) throws Exception {

HandlerInterceptor[] interceptors = getInterceptors();

if (!ObjectUtils.isEmpty(interceptors)) {

for (int i = 0; i < interceptors.length; i++) {

HandlerInterceptor interceptor = interceptors[i];

if (!interceptor.preHandle(request, response, this.handler)) {

triggerAfterCompletion(request, response, null);

return false;

}

this.interceptorIndex = i;

}

}

return true;

}

/*

* 执行已经注册的拦截器 postHandle()方法。

*/

void applyPostHandle(HttpServletRequest request, HttpServletResponse response, ModelAndView mv) throws Exception {

HandlerInterceptor[] interceptors = getInterceptors();

if (!ObjectUtils.isEmpty(interceptors)) {

for (int i = interceptors.length - 1; i >= 0; i--) {

HandlerInterceptor interceptor = interceptors[i];

interceptor.postHandle(request, response, this.handler, mv);

}

}

}

/**

* 这个方法只会执行preHandle()方法已经成功执行并且返回true的拦截器中的postHandle()方法。

*/

void triggerAfterCompletion(HttpServletRequest request, HttpServletResponse respohttp://nse, Exception ex)

throws Exception {

HandlerInterceptor[] interceptors = getInterceptors();

if (!ObjectUtils.isEmpty(interceptors)) {

for (int i = this.interceptorIndesylxgQbx; i >= 0; i--) {

HandlerInterceptor interceptor = interceptors[i];

try {

interceptor.afterCompletion(request, response, this.handler, ex);

}

catch (Throwable ex2) {

logger.error("HandlerInterceptor.afterCompletion threw exception", ex2);

}

}

}

}

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。