Annotation配置Interceptor

最新推荐文章于 2023-11-16 16:34:56 发布

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#配置管理 #Struts #Apache #JSP #XML

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本文介绍如何使用Struts2框架中的注解来配置拦截器，包括@Before、@After和@BeforeResult等注解的具体应用。通过示例展示了拦截器在Action执行前后及结果处理前的工作流程。

利用注解配置拦截器：

在xwork包下有：

com.opensymphony.xwork2.interceptor.annotations.After.class

com.opensymphony.xwork2.interceptor.annotations.Before.class

com.opensymphony.xwork2.interceptor.annotations.BeforeResult.class

com.opensymphony.xwork2.interceptor.annotations.AnnotationWorkflowInterceptor.class

它们是用来配置annotation的。其中前三个依赖于AnnotationWorkflowInterceptor。下面用例子介绍一下：

<%@ taglib prefix="s" uri="/struts-tags" %>
<body>
    <s:form method="POST" action="login.action">
    	<s:textfield name="user.username" label="Username:"></s:textfield>
    	<s:password name="user.password" label="Password:"></s:password>
    	<s:submit value="提交"></s:submit>
    </s:form>
  </body>

<filter>
  	<filter-name>struts2</filter-name>
  	<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>struts2</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
	<package name="annotation" extends="struts-default">
		<interceptors>
			<interceptor name="annotationInterceptor" class="com.opensymphony.xwork2.interceptor.annotations.AnnotationWorkflowInterceptor"></interceptor>
		</interceptors>
		<action name="login" class="com.zchen.action.LoginAction" >
			<result name="success">index.jsp</result>
			<interceptor-ref name="annotationInterceptor"></interceptor-ref>
			<interceptor-ref name="defaultStack"></interceptor-ref>
		</action>
	</package>
</struts>

package com.zchen.action;

import java.util.Map;

import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.interceptor.annotations.After;
import com.opensymphony.xwork2.interceptor.annotations.Before;
import com.opensymphony.xwork2.interceptor.annotations.BeforeResult;
import com.zchen.model.User;

public class LoginAction extends ActionSupport implements SessionAware {
	private static final long serialVersionUID = 4387832093273420762L;
	private User user = null;
	
	public User getUser() {
		return user;
	}



	public void setUser(User user) {
		this.user = user;
	}



	@Override
	public String execute() throws Exception {
		System.out.println("action方法");
		System.out.println(user.getUsername());
		System.out.println(user.getPassword());
		return super.execute();
	}


    @Before
    public void doBefore() {
    	System.out.println("action执行之前方法被调用");
	}
    
    @After
    public void doAfter() {
    	System.out.println("action执行之后方法被调用");
	}
    @BeforeResult
    public void doBeforeResult() {
    	System.out.println("result执行之前方法被调用");
	}
    
	public void setSession(Map<String, Object> arg0) {

	}

}

package com.zchen.model;

public class User {
	
	private String username;
	
	private String password;

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}
	
	

}

此时输出顺序是：

         action执行之前方法被调用
        action方法
        admin
         1234
         result执行之前方法被调用
         action执行之后方法被调用

所以我们可以用这种配置判断用户是否登录，只有登录了才可以访问页面：

（我们单写一个Action类作为权限管理简要代码如下）

package com.zchen.action;

import java.util.Map;

import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;

public class AnthInterceptor extends ActionSupport implements SessionAware {
	private static final long serialVersionUID = 4387832093273420762L;
	Map session;
	public String doBefore(){
		if(session.get("login")==null){
			//如果没有session表示用户还没有登录
			return Action.LOGIN;
		}else{
			//返回null表示程序继续执行execute方法而此方法默认返回success
			return null;
		}
	}
	public void setSession(Map<String, Object> session) {
		this.session = session;
	}

}

在struts.xml中配置即可。