Struts2_访问Web元素

取得Map 类型的 request,session,application, HttpServletRequest,HttpSession,ServletContext的引用。

分访问 Map 类型和原始类型两种。

1、获取 Map 类型的request,session,application（ Map 类型）的第一种方式，他们保存在都ActionContext中：

package com.bjsxt.struts2.user.action;

import java.util.Map;

import com.bjsxt.struts2.user.model.User;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction1 extends ActionSupport{
    
    private static final long serialVersionUID = -7767523825141043349L;
    
    private Map request;
    private Map session;
    private Map application;
    
    private User user;
    
    public LoginAction1(){
        //在 对应方法中或者在构造方法中获取都一样
        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;
    }

    public User getUser() {
        return user;
    }

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

jsp页面的访问：

<s:property value="#request.r1"/>
<s:property value="#session.s1"/>
<s:property value="#application.a1"/>

2、获取 Map 类型的request,session,application的第一种方式，一般用这种就行了：

实现了RequestAware,SessionAware,ApplicationAware 这三个接口，这种方式是通过Struts2把这三个对象注入给Action的。

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.bjsxt.struts2.user.model.User;
import com.opensymphony.xwork2.ActionSupport;

/**
 * 只用这种
 * @author Administrator
 *
 */
public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{
    
    private static final long serialVersionUID = -7767523825141043349L;
    
    private Map<String, Object> request;
    private Map<String, Object> session;
    private Map<String, Object> application;
    
    private User user;
    
    public String execute(){
        request.put("r1", "r1");
        session.put("s1", "s1");
        application.put("a1", "a1");
        return SUCCESS;
    }

    public User getUser() {
        return user;
    }

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

    public Map<String, Object> getRequest() {
        return request;
    }

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

    public Map<String, Object> getSession() {
        return session;
    }

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

    public Map<String, Object> getApplication() {
        return application;
    }

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

获取的方式跟第一种是一样的。

3、获取 HttpServletRequest,HttpSession,ServletContext （原始类型）的第一种方式：

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 static final long serialVersionUID = -7767523825141043349L;
    
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    
    public LoginAction3(){
        request = ServletActionContext.getRequest();
        session = request.getSession();
        application = session.getServletContext();
    }
    
    public String execute(){
        
        return SUCCESS;
    }
}

取值，要是request、session、application中存在这个属性的话：

<%=request.getAttribute("r1") %>
<%=session.getAttribute("s1") %>
<%=application.getAttribute("a1") %>

4、获取 HttpServletRequest,HttpSession,ServletContext （原始类型）的第二种方式：

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 org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction4 extends ActionSupport implements ServletRequestAware{
    
    private static final long serialVersionUID = -7767523825141043349L;
    
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    
    public String execute(){
        return SUCCESS;
    }

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

取值方式和第三种一样。

补充：

 <s:property value="#attr.r1"/> 2 <s:property value="#attr.s1"/> 3 <s:property value="#attr.a1"/> 

这种获取方式会去ActionContext中遍历查找，所有的r1、s1、a1的值，一般情况下我们都会知道变量的值精确存放点，不推荐使用这个取值方式。

链接: http://pan.baidu.com/s/1pLk9ZCJ 密码: idbm