SpringMVC框架
10.3 实验代码(多个拦截器)
- 自定义拦截器类(两个)
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package com.atguigu.springmvc.interceptors;
import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView;
public class FirstHandlerInterceptor implements HandlerInterceptor {
@Override public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception { System.out.println(this.getClass().getName() + " - afterCompletion"); }
@Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { System.out.println(this.getClass().getName() + " - postHandle"); }
@Override public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception { System.out.println(this.getClass().getName() + " - preHandle"); return true; }
} |
package com.atguigu.springmvc.interceptors;
import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView;
public class SecondHandlerInterceptor implements HandlerInterceptor {
@Override public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception { System.out.println(this.getClass().getName() + " - afterCompletion"); }
@Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { System.out.println(this.getClass().getName() + " - postHandle"); }
@Override public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception { System.out.println(this.getClass().getName() + " - preHandle"); return true; }
} |
- 配置自定义拦截器
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<mvc:interceptors> <!-- 声明自定义拦截器 --> <bean id="firstHandlerInterceptor" class="com.atguigu.springmvc.interceptors.FirstHandlerInterceptor"></bean> <!-- 配置拦截器引用 --> <mvc:interceptor> <mvc:mapping path="/empList"/> <!-- <mvc:exclude-mapping path="/empList"/> --> <bean id="secondHandlerInterceptor" class="com.atguigu.springmvc.interceptors.SecondHandlerInterceptor"></bean> </mvc:interceptor> </mvc:interceptors> |
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两个都是返回true : com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - preHandle com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - preHandle ************************************biz method******************************* com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - postHandle com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - postHandle com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - afterCompletion com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - afterCompletion |
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两个都是返回false: com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - preHandle |
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true,false com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - preHandle com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - preHandle com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - afterCompletion |
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false,true |
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com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - preHandle |
10.4 多个拦截方法的执行顺序
- 关于执行顺序
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com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - preHandle com.atguigu.springmvc.interceptors.SecondHandlerInterceptor – preHandle ************************************biz method******************************* com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - postHandle com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - postHandle com.atguigu.springmvc.interceptors.SecondHandlerInterceptor - afterCompletion com.atguigu.springmvc.interceptors.FirstHandlerInterceptor - afterCompletion |
- 执行顺序图解
- 从源代码的执行角度分析流程：
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boolean applyPreHandle(HttpServletRequest request, HttpServletResponse response) throws Exception { if (getInterceptors() != null) { for (int i = 0; i < getInterceptors().length; i++) { HandlerInterceptor interceptor = getInterceptors()[i]; if (!interceptor.preHandle(request, response, this.handler)) { triggerAfterCompletion(request, response, null); return false; } this.interceptorIndex = i; } } return true; } |
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void applyPostHandle(HttpServletRequest request, HttpServletResponse response, ModelAndView mv) throws Exception { if (getInterceptors() == null) { return; } for (int i = getInterceptors().length - 1; i >= 0; i--) { HandlerInterceptor interceptor = getInterceptors()[i]; interceptor.postHandle(request, response, this.handler, mv); } } |
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void triggerAfterCompletion(HttpServletRequest request, HttpServletResponse response, Exception ex) throws Exception {
if (getInterceptors() == null) { return; } for (int i = this.interceptorIndex; i >= 0; i--) { HandlerInterceptor interceptor = getInterceptors()[i]; try { interceptor.afterCompletion(request, response, this.handler, ex); } catch (Throwable ex2) { logger.error("HandlerInterceptor.afterCompletion threw exception", ex2); } } } |
- 源码分析：分析interceptorIndex的值情况
