Struts2获取web对象的4种方式

Struts2获取web对象的4种方式

Struts2是如何获取web中 request、session、application的了，Struts2有4种方式获取web对象

1.通过ServletActionContext取HttpServletRequest对象

2.通过ServletRequestAware，(ServletResponseAware )来注入HttpServletRequest、(HttpServletResponse)对象

3.通过ActionContext取Map

4.通过RequestAware,SessionAware,ApplicationAware接口，来注入  三个Map

下面的例子就用以上4种方式来实现如何获取web对象

首先建立一个实体类,接收从客户端传过来的参数,通过ModelDriven，如果对传递参数不明白的可以参看我上篇文章 三种对象传参和ModelDriven的原理


一个Student实体类

package com.yc.web.actions;

import java.io.Serializable;

public class Student implements Serializable {
private static final long serialVersionUID = -6646865822958505769L;
private String name;
private Integer age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}

一、通过ServletActionContext取HttpServletRequest对象

package com.yc.web.actions;

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

import org.apache.struts2.ServletActionContext;

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

public class StudentAction extends ActionSupport implements ModelDriven<Student>{
private static final long serialVersionUID = 1213446993015542840L;
private Student student;
private HttpServletRequest request;
private HttpSession session;
private ServletContext application;
private HttpServletResponse response;

public  StudentAction() {
//获取web对象
request=ServletActionContext.getRequest();
session=request.getSession();
application=session.getServletContext();
}
public String execute(){
//赋值
request.setAttribute("student", student);
session.setAttribute("student", student);
application.setAttribute("student", student);
return Action.SUCCESS;
}
@Override
public Student getModel() {
student =new Student();
return student;
}
}

二、通过ServletRequestAware(ServletResponseAware )来注入HttpServletRequest(HttpServletResponse)对象

package com.yc.web.actions;

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

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;

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

public class StudentAction2 extends ActionSupport implements
ModelDriven<Student> ,ServletRequestAware,ServletResponseAware{
private static final long serialVersionUID = 1213446993015542840L;
private Student student;
private HttpServletRequest request;
private HttpSession session;
private ServletContext application;
private HttpServletResponse response;

@Override
public Student getModel() {
student =new Student();
return student;
}
@Override
public void setServletResponse(HttpServletResponse arg0) {
//获取response对象
response=arg0;
}

@Override
public void setServletRequest(HttpServletRequest arg0) {
//获取web对象
request=arg0;
session=request.getSession();
application=session.getServletContext();
}

public String execute(){
//赋值
request.setAttribute("student", student);
session.setAttribute("student", student);
application.setAttribute("student", student);
return Action.SUCCESS;

}
}

三、通过ActionContext取Map

package com.yc.web.actions;

import java.util.Map;

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

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;

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

public class StudentAction3 extends ActionSupport implements ModelDriven<Student>{
private static final long serialVersionUID = 1213446993015542840L;
private Student student;
private Map<String ,Object> request;
private Map<String ,Object> session;
private Map<String ,Object> application;
public  StudentAction3() {
//获取web对象
request=(Map<String, Object>) ActionContext.getContext().get("request");
session=ActionContext.getContext().getSession();
application=ActionContext.getContext().getApplication();
}
public String execute(){
//赋值
request.put("student", student);
session.put("student", student);
application.put("student", student);
return Action.SUCCESS;

}
@Override
public Student getModel() {
student =new Student();
return student;
}
}

四、通过RequestAware,SessionAware,ApplicationAware接口，来注入  三个Map

package com.yc.web.actions;

import java.util.Map;

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

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.ApplicationAware;
import org.apache.struts2.interceptor.RequestAware;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.interceptor.SessionAware;

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

import freemarker.template.utility.Execute;

public class StudentAction4 extends ActionSupport implements
ModelDriven<Student> ,RequestAware,SessionAware,ApplicationAware{
private static final long serialVersionUID = 1213446993015542840L;
private Student student;
private Map<String ,Object> request;
private Map<String ,Object> session;
private Map<String ,Object> application;

public String execute(){
//赋值
request.put("student", student);
session.put("student", student);
application.put("student", student);
return Action.SUCCESS;

}

@Override
public Student getModel() {
student =new Student();
return student;
}
//获取web对象
@Override
public void setApplication(Map<String, Object> arg0) {
application=arg0;
}
@Override
public void setSession(Map<String, Object> arg0) {
session=arg0;

}
@Override
public void setRequest(Map<String, Object> arg0) {
request=arg0;
}
}

下面是访问页面 index,jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>

</body>
<a href="student.action?name=tg&age=20">学生 </a>
<a href="student2.action?name=tg&age=20">学生 </a>
<a href="student3.action?name=tg&age=20">学生 </a>
<a href="student4.action?name=tg&age=20">学生 </a>
</html>

下面struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="true" />
<constant name="struts.action.extension" value="action,do,,"/>

<package name="default" namespace="/" extends="struts-default">

<action name="student" class="com.yc.web.actions.StudentAction">
<result name="success">/show.jsp</result>
</action>

<action name="student2" class="com.yc.web.actions.StudentAction2">
<result name="success">/show.jsp</result>
</action>

<action name="student3" class="com.yc.web.actions.StudentAction3">
<result name="success">/show.jsp</result>
</action>

<action name="student4" class="com.yc.web.actions.StudentAction4">
<result name="success">/show.jsp</result>
</action>

<action name="student4" class="com.yc.web.actions.StudentAction4">
<result name="success">/show.jsp</result>
</action>
</package>

</struts>

访问成功显示页面show.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
${requestScope.student.name}   -${requestScope.student.age}  <br/>
${sessionScope.student.name}   -${sessionScope.student.age} <br/>
${applicationScope.student.name} -${applicationScope.student.age}  <br/>
</body>
</html>