搭建环境:
引入jar包,src下建立struts.xml文件
项目配置文件web.xml.
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>struts2Test</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list> <filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter> <filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping> </web-app>
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" /> <package name="default" namespace="/gys" extends="struts-default">
<action name="test" class="action.GetServletAPIAction">
<result name="api">/servletApi.jsp</result>
</action>
</package>
</struts>
Struts2的Action类并不直接与任何Servlet API耦合,这是Struts2的一个改良之处,因为Action类不在于Servlet API耦合,从而能更轻松地测试该Action.
Web中通常访问Servlet API就是HttpServletRequest,HttpSession和ServletContext,这3个类分别代表JSP内置对象中的request,session,application.
Struts2提供了一个ActionContext类来访问API,
该类提供了几个常用的方法:
Object get(Object key):该方法类似于调用HttpServletRequest的getAttribute(String name)方法.
Map getApplication():返回一个Map对象,该对象模拟了ServletContext实例.
static ActionContext getContext():静态方法,获取系统的ActionContext实例.
Map getParameters():获取所有的请求参数.类似于调用HttpServletRequest对象的getParameterMap方法.
Map getSession()返回一个Map对象,模拟了HttpSession实例.
void setApplication(Map application)直接传入一个Map实例,将该Map实例里的key-value转换成application的属性名,属性值.
void setSession(Map session)直接传入一个Map实例,将该Map实例里的key-value转换成session的属性名,属性值.
建立action类:
package action;
import com.opensymphony.xwork2.ActionContext;
public class GetServletAPIAction {
private String name;
private String pass;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
}
public void getServletAPI1(){
//获取ActionContext实例,通过该实例访问Servlet API
ActionContext ctx=ActionContext.getContext();
//获取ServletContext里的count属性
Integer count=(Integer)ctx.getApplication().get("count");
if(count==null){
count=1;
}
else {
count++;
}
//将访问人数设置成application的一个属性
ctx.getApplication().put("count", count);
ctx.getSession().put("username", "思思博士");
}
public String execute(){
getServletAPI1();
return "api";
}
}
建立页面servletApi.jsp:
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head> <body>
<h1>访问次数:${applicationScope.count }</h1>
<h1>登陆人:${sessionScope.username }</h1>
</body>
</html>
测试一下:
虽然Struts2提供了ActionCotext来访问Servlet API,但这种访问毕竟不能直接获得Servlet API实例,为了在Action中直接访问Servlet API,struts2还提供了如下系统接口.
ServletContextAware:实现该接口的Action可以直接访问web应用的ServletContext实例.
ServletRequestAwart:实现该接口的Action可以直接访问用户请求的HttpServletRequest实例
ServletResponseAware:实现该接口的Action可以直接访问服务器响应的HttpServletResponse实例.
下面以ServletRequestAware为例,介绍如何在Action中访问HttpServletRequest对象.
修改上面的代码:
ServletApi.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head> <body>
<%-- <h1>访问次数:${applicationScope.count }</h1>
<h1>登陆人:${sessionScope.username }</h1> --%>
<h3>${requestScope.API }</h3>
</body>
</html>
GetServletAPIAction.java
package action; import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware; import com.opensymphony.xwork2.ActionContext; public class GetServletAPIAction implements ServletRequestAware{
private HttpServletRequest request; private String name;
private String pass;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
} public void getServletAPI1(){
//获取ActionContext实例,通过该实例访问Servlet API
ActionContext ctx=ActionContext.getContext();
//获取ServletContext里的count属性
Integer count=(Integer)ctx.getApplication().get("count");
if(count==null){
count=1;
}
else {
count++;
}
//将访问人数设置成application的一个属性
ctx.getApplication().put("count", count);
ctx.getSession().put("username", "思思博士"); }
public void getServletAPI2(){
request.setAttribute("API","我来自于struts2中直接访问servletAPI的request");
} @Override
public void setServletRequest(HttpServletRequest request) {
this.request=request;
}
public String execute(){
//getServletAPI1();
getServletAPI2();
return "api";
} }
测试结果:
