Struts2--访问web元素

后台action不能通过request等获取前台数据, 如果有人登陆了, 会往session设定值, 怎么实现呢?

action如何往session里设定值?

所以action访问 request, session,application等web元素的方法?

总结:

1. jsp调用action

2. action里 用map的IoC方法给session赋值

　　public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware

　　session.put("s1", "name");

3. 在jsp显示里用  <s:property value="#request.变量名"/> 调用变量

   也可以通过 <s:property value="#parameters.name"/> 

只介绍一种最常用的:

1. jsp页面显示: 4个按钮分别提交同一个form的方法:

<form name="f" action="" method="post">
用户名：<input type="text" name="name"/>
密码：<input type="text" name="password"/>
<br />
<input type="button" value="submit1" onclick="javascript:document.f.action='login/login1';document.f.submit();" />
<input type="button" value="submit2" onclick="javascript:document.f.action='login/login2';document.f.submit();" />
<input type="button" value="submit3" onclick="javascript:document.f.action='login/login3';document.f.submit();" />
<input type="button" value="submit4" onclick="javascript:document.f.action='login/login4';document.f.submit();" />
</form>

　

2. struts.xml配置:

 <package name="login" extends="struts-default" namespace="/login">
        <action name="login*" class="com.bjsxt.struts2.user.action.LoginAction{1}">
            <result>/user_login_success.jsp</result>
        </action>
    </package>

3. action 的4种处理方法:

loginAction1.java: 取得Map类型的方法

package com.bjsxt.struts2.user.action;

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction1 extends ActionSupport {
	
	private Map request;
	private Map session;
	private Map application;
	
	public LoginAction1() {
		request = (Map)ActionContext.getContext().get("request");
		session = ActionContext.getContext().getSession();
		application = ActionContext.getContext().getApplication();
	}
	
	public String execute() {
		request.put("r1", "r1");
		session.put("s1", "s1");
		application.put("a1", "a1");
		return SUCCESS; 
	}	
}

loginAction2.java: 取得Map类型的 IoC方法: 最常用

package com.bjsxt.struts2.user.action;

import java.util.Map;

import org.apache.struts2.interceptor.ApplicationAware;
import org.apache.struts2.interceptor.RequestAware;
import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {
	
	private Map<String, Object> request;
	private Map<String, Object> session;
	private Map<String, Object> application;
	
	//DI dependency injection
	//IoC inverse of control
	public String execute() {
		request.put("r1", "r1");
		session.put("s1", "s1");
		application.put("a1", "a1");
		return SUCCESS; 
	}

	@Override
	public void setRequest(Map<String, Object> request) {
		this.request = request;
	}

	@Override
	public void setSession(Map<String, Object> session) {
		this.session = session;
	}

	@Override
	public void setApplication(Map<String, Object> application) {
		this.application = application;
	}	
}

loginAction3.java: 取得真实类型的 方法:　　

package com.bjsxt.struts2.user.action;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction3 extends ActionSupport {
	
	private HttpServletRequest request;
	private HttpSession session;
	private ServletContext application;
	
	public LoginAction3() {
		request = ServletActionContext.getRequest();
		session = request.getSession();
		application = session.getServletContext();
	}
	
	public String execute() {
		request.setAttribute("r1", "r1");
		session.setAttribute("s1", "s1");
		application.setAttribute("a1", "a1");
		return SUCCESS; 
	}
	
}

loginAction4.java: 取得真实类型的 IoC 方法:

package com.bjsxt.struts2.user.action;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction4 extends ActionSupport implements ServletRequestAware {
	
	private HttpServletRequest request;
	private HttpSession session;
	private ServletContext application;	
	
	public String execute() {
		request.setAttribute("r1", "r1");
		session.setAttribute("s1", "s1");
		application.setAttribute("a1", "a1");
		return SUCCESS; 
	}

	@Override
	public void setServletRequest(HttpServletRequest request) {
		this.request = request;
		this.session = request.getSession();
		this.application = session.getServletContext();
	}	
}

　　

最后如何在jsp中拿到request等值:  <s:property value="#request.变量名"/> 

#代表提取的不是 valuestack里的内容,而是context里的值

<body>
	User Login Success!
	<br />
	<s:property value="#request.r1"/> | <%=request.getAttribute("r1") %> <br />
	<s:property value="#session.s1"/> | <%=session.getAttribute("s1") %> <br />
	<s:property value="#application.a1"/> | <%=application.getAttribute("a1") %> <br />
	<s:property value="#parameters.name"/>  <br />
	<s:property value="#parameters.password"/> <br />
	<s:property value="#attr.a1"/><br />
	<s:property value="#attr.s1"/><br />
	<s:property value="#attr.r1"/><br />
	<s:debug></s:debug>
	<br />
</body>