Struts2_Action记录在线人数实例
在写该实例前先来说个
关于Struts2请求拓展名问题
1）org.apache.struts2 包下的default.properties中配置了struts2应用中的一些常量
2）struts.action.extension定义了当前Struts2应用可以接受的请求的拓展名；
3）可以在struts.xml文件中以常量配置方式修改default.properties所配置的常量
<constant name="struts.action.extension" value="action,do,"></constant>
接下来给出实例
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>
<form action="loginin.do" method="post">
用户名<input type="text" name="username"/>
<br><br>
<input type="submit" value = "submit"/>
</form>
</body>
</html>
success.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>
welcome: ${sessionScope.username}
<br><br>
共有 ${applicationScope.count} 位访问者
<a href="loginout.do">退出</a>
</body>
</html>
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.action.extension" value="action,do,"></constant>
<package name="default" extends="struts-default">
<action name="loginin" class="cn.zucc.wul.LoginInAction">
<result name="loginin-success">/success.jsp</result>
</action>
<action name="loginout" class="cn.zucc.wul.LoginInAction" method="tuichu" >
<result name="loginout-success">/index.jsp</result>
</action>
</package>
</struts>
LoginInAction.java
package cn.zucc.wul;
import java.util.Map;
import java.util.Set;
import org.apache.struts2.dispatcher.SessionMap;
import org.apache.struts2.interceptor.ApplicationAware;
import org.apache.struts2.interceptor.SessionAware;
public class LoginInAction implements SessionAware,ApplicationAware{
private String username;
private Map<String, Object> session;
private Map<String, Object> application;
public void setUsername(String username) {
this.username = username;
}
public String execute(){
//把用户信息存入Session域中
//1.获取session，通过实现SessionAware接口
//2.获取登录信息，通过Action中添加的setter方法
//3.把用户信息存入Session域中
session.put("username", username);
//在线人数+1
//1.获取当前在线人数，从application中获取
Integer count = (Integer) application.get("count");
if(count == null){
count=0;
}
//2.使当前在线人数+1
count++;
application.put("count", count);
return "loginin-success";
}
public String tuichu(){
//1.在线人数 -1 ：获取在线人数，若数量 >0 ， 则 -1
Integer count = (Integer) application.get("count");
if(count != null && count > 0){
count--;
application.put("count", count);
}
//2.session失效，强转为SessionMap，调用invalidate方法使其失效
((SessionMap)session).invalidate();
return "loginout-success";
}
@Override
public void setApplication(Map<String, Object> application) {
this.application = application;
}
@Override
public void setSession(Map<String, Object> session) {
this.session = session;
}
}
直接输入http://localhost:8080/struts2_5/success.jsp查看
