介紹

實現aop的方式

用於實現action之前,之後執行

一般用於事物操作.

一般用於對某些未授權的頁面訪問的時候,進行攔截操作,攔截非法訪問.

開箱即用攔截器

 
 <interceptor-ref> 
 <interceptor-ref> 

必須有傳遞屬性這個攔截器

運行輸出日誌如下

2019-03-24 03:50:19.231 [DEBUG] com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:67) - Checking access for [target: com.ming.HelloWorldAction@33e67d25, member: public java.lang.String com.ming.HelloWorldAction.getName(), property: name]
2019-03-24 03:50:19.232 [INFO ] com.opensymphony.xwork2.interceptor.TimerInterceptor.doLog(TimerInterceptor.java:205) - Executed action [//hello!execute] took 12 ms.

可以看到這個action一共運行耗時12ms

自定義攔截器

需要繼承該抽象類,並實現其方法 即 com.opensymphony.xwork2.interceptor.AbstractInterceptor 抽象類

代碼如下

package com.ming;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
public class MyInterceptor extends AbstractInterceptor {
 /** 

 * Override to handle interception
 *
 * @param invocation
 */
 @Override
 public String intercept(ActionInvocation invocation) throws Exception {
 return null;
 }
}

實現該類的interceptor方法

package com.ming;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class MyInterceptor extends AbstractInterceptor {
 /**
 * Override to handle interception
 *
 * @param invocation
 */
 @Override
 public String intercept(ActionInvocation invocation) throws Exception {
 Logger logger = LogManager.getLogger();
 // 執行結果前
 String output = "hi before";
 logger.info(output);
 
 // 開始執行Action
 String result = invocation.invoke();
 
 // 執行結果後
 output = "hi after";
 logger.info(output);
 
 // 繼續傳遞到下一個攔截器
 return result;
 }
}

更改配置文件

  

 <interceptor-ref> 
 <interceptor-ref> 
 <interceptor-ref>
 
 <result>/HelloWorld.jsp/<result>
 <result>/error.html/<result>

效果如下

控制檯輸出結果如下

2019-03-24 04:37:24.086 [DEBUG] com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:67) - Checking access for [target: com.ming.HelloWorldAction@5121691d, member: public void com.ming.HelloWorldAction.setName(java.lang.String), property: name]
2019-03-24 04:37:24.087 [INFO ] com.ming.MyInterceptor.intercept(MyInterceptor.java:19) - hi before
2019-03-24 04:37:24.089 [DEBUG] com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:430) - Executing action method = execute
2019-03-24 04:37:24.106 [DEBUG] com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:67) - Checking access for [target: com.ming.HelloWorldAction@5121691d, member: public java.lang.String com.ming.HelloWorldAction.execute() throws java.lang.Exception, property: null]
2019-03-24 04:37:24.143 [DEBUG] com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:67) - Checking access for [target: org.apache.struts2.result.ServletDispatcherResult@2e4369c6, member: public void org.apache.struts2.result.StrutsResultSupport.setLocation(java.lang.String), property: location]
2019-03-24 04:37:24.143 [DEBUG] com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:67) - Checking access for [target: org.apache.struts2.result.ServletDispatcherResult@2e4369c6, member: public void org.apache.struts2.result.StrutsResultSupport.setLocation(java.lang.String), property: location]
2019-03-24 04:37:24.150 [DEBUG] org.apache.struts2.result.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:127) - Forwarding to location: /error.html
2019-03-24 04:37:24.158 [DEBUG] com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler.nullPropertyValue(InstantiatingNullHandler.java:98) - Entering nullPropertyValue [target=[com.ming.HelloWorldAction@5121691d, com.opensymphony.xwork2.DefaultTextProvider@2e34626e], property=struts]
2019-03-24 04:37:24.175 [INFO ] com.ming.MyInterceptor.intercept(MyInterceptor.java:26) - hi after
2019-03-24 04:37:24.176 [INFO ] com.opensymphony.xwork2.interceptor.TimerInterceptor.doLog(TimerInterceptor.java:205) - Executed action [//hello!execute] took 89 ms.

可以看到,由於配置了3個攔截器,攔截器被順序執行.

在執行前後分別執行了兩個操作

這就是面向切面編程

此處可以添加事物 鎖 其中鎖可以用redis實現,達到同時多個tomcat實例讀取數據庫的時候,進行加鎖操作,使用redis達到鎖的目的

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關鍵字: SecurityMemberAccess 攔截 xwork2