struts2 在拦截器进行注入（依据Action是否实现自己定义接口）

比如：经常在Action中都须要获取当前登录的User，就须要获取Session。然后从Session获取当前登录的User，由于这些步骤都是反复操作，能够想办法在拦截器中进行实现。能够自己定义一个接口。仅仅要你的Action实现了这个接口。就在自己定义拦截器中进行注入。

即从拦截器中获取Session，然后设置进行注入。

简单的样例：

一个自己定义接口，仅仅要Action实现这个接口，就在拦截器中进行注入

package com.atguigu.surveypark.struts2;
 
import com.atguigu.surveypark.model.User;
 
/**
 * 用户关注
 */
public interface UserAware {
	public void setUser(User user);
}

一个自己定义拦截器（登录拦截器）：在拦截器中获取action的实例，假设实现上面的接口就进行注入。即调用接口的方法。

package com.atguigu.surveypark.struts2.interceptor;
 
import com.atguigu.surveypark.model.User;
import com.atguigu.surveypark.struts2.UserAware;
import com.atguigu.surveypark.struts2.action.BaseAction;
import com.atguigu.surveypark.struts2.action.LoginAction;
import com.atguigu.surveypark.struts2.action.RegAction;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;
 
/**
 * 登陆拦截器
 */
public class LoginInterceptor implements Interceptor {
 
	private static final long serialVersionUID = 4230211839075439660L;
 
	public void destroy() {
	}
 
	public void init() {
	}
 
	@SuppressWarnings("rawtypes")
	public String intercept(ActionInvocation arg0) throws Exception {
		BaseAction action = (BaseAction) arg0.getAction();
		if(action instanceof LoginAction
				|| action instanceof RegAction){
			return arg0.invoke();
		}
		else{
			User user = (User) arg0.getInvocationContext().getSession().get("user");
			if(user == null){
				//去登陆
				return "login" ;
			}
			else{
				//放行
				if(action instanceof UserAware){
					//注入user给action
					((UserAware)action).setUser(user);
				}
				return arg0.invoke();
			}
		}
	}
}

Action：一个实现接口的Action

package com.atguigu.surveypark.struts2.action;
 
import java.util.List;
 
import javax.annotation.Resource;
 
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
 
import com.atguigu.surveypark.model.Survey;
import com.atguigu.surveypark.model.User;
import com.atguigu.surveypark.service.SurveyService;
import com.atguigu.surveypark.struts2.UserAware;
 
/**
 * SurveyAction
 */
@Controller
@Scope("prototype")
public class SurveyAction extends BaseAction<Survey> implements UserAware{
 
	private static final long serialVersionUID = 2438909978838628762L;
 
	//注入SurveyService
	@Resource
	private SurveyService surveyService ;
 
	//调查集合
	private List<Survey> mySurveys ;
 
	//接受user对象
	private User user;
 
	public List<Survey> getMySurveys() {
		return mySurveys;
	}
 
	public void setMySurveys(List<Survey> mySurveys) {
		this.mySurveys = mySurveys;
	}
 
	/**
	 * 查询我的调查列表
	 */
	public String mySurveys(){
		this.mySurveys = surveyService.findMySurveys(user);
		return "mySurveyListPage" ;
	}
 
	/**
	 * 新建调查
	 */
	public String newSurvey(){
		this.model = surveyService.newSurvey(user);
		return "designSurveyPage" ;
	}
 
	//注入User对象
	public void setUser(User user) {
		this.user = user ;
	}
}

struts.xml：拦截器注冊

<?
 
xml version="1.0"?>
<!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
	"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
	<!-- 主题 -->
	<constant name="struts.ui.theme" value="simple" />
	<!-- 开发模式 -->
	<constant name="struts.devMode" value="true" />
 
	<package name="surveyparkPkg" extends="struts-default" namespace="/">
		<interceptors>
			<!-- 注冊登陆拦截器 -->
			<interceptor name="loginInterceptor" class="com.atguigu.surveypark.struts2.interceptor.LoginInterceptor" />
			<!-- 定义拦截器栈 -->
			<interceptor-stack name="surveyparkStack">
				<interceptor-ref name="loginInterceptor" />
				<interceptor-ref name="defaultStack" />
			</interceptor-stack>
		</interceptors>
 
		<!-- 定义默认栈 -->
		<default-interceptor-ref name="surveyparkStack" />
 
		<!-- 定义全局结果 -->
		<global-results>
			<result name="login">/index.jsp</result>
		</global-results>
 
		<!-- regAction -->
		<action name="RegAction_*" class="regAction" method="{1}">
			<result name="regPage">/reg.jsp</result>
			<result name="input">/reg.jsp</result>
			<result name="success">/index.jsp</result>
		</action>
		<!-- loginAction -->
		<action name="LoginAction_*" class="loginAction" method="{1}">
			<result name="loginPage">/index.jsp</result>
			<result name="input">/index.jsp</result>
			<result name="success">/index.jsp</result>
		</action>
 
		<!-- SurveyAction -->
		<action name="SurveyAction_*" class="surveyAction" method="{1}">
			<result name="mySurveyListPage">/mySurveyList.jsp</result>
			<result name="designSurveyPage">/designSurvey.jsp</result>
		</action>
	</package>
</struts>