实例说明
根据上两次的成品进行二次加工。
加入Listener，监听用户的登陆注销情况。
所用知识说明
采用SessionBindingListener对Session进行监听。
同时，Action中获取Application，Session，request的方法（在此只列出一种）更多方法
代码语言：javascript复制 public class LoginAction {
private Map request;
private Map session;
private Map application;
public String execute() {
request = (Map)ActionContext.getContext().get("request");
session = ActionContext.getContext().getSession();
application = ActionContext.getContext().getApplication();
request.put("username1", "jingjing1");
session.put("username2", "jingjing2");
application.put("username3", "jingjing3");
return "success";
}
} 代码实例
登陆控制UserManagment
代码语言：javascript复制package UserBlock;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionContext;
import javafx.application.Application;
import org.apache.struts2.views.util.ContextUtil;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;
import java.util.ArrayList;
import java.util.Map;
/**
* Servlet监听器，控制记录用户的登陆注销信息
* Created by Richard on 2017/6/16.
*/
public class UserManagment {
class Userlistener implements HttpSessionBindingListener{
private String username;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@Override
public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent) {
ActionContext context = ActionContext.getContext();
Map application = context.getApplication();
ArrayList online= (ArrayList) application.get("online");
if(online==null){
online=new ArrayList();
}
online.add(username);
application.put("online",online);
}
@Override
public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent) {
ActionContext context = ActionContext.getContext();
Map application = context.getApplication();
ArrayList online= (ArrayList) application.get("online");
online.remove(username);
}
}
/*
登陆
首先判别是否登陆
已经登陆---->return
没有登陆---->获取对应的Session，存入对应用户名的listener
*/
public void login(String username){
if(islogin(username)){
return;
}else{
Userlistener newUser=new Userlistener();
newUser.setUsername(username);
ActionContext actionContext=ActionContext.getContext();
Map session=actionContext.getSession();
session.put("username",newUser);
}
}
/*
判断是否登陆：
判别条件Session中是否有对应的该用户名的Listener
有--->已经登陆，未注销
无--->没有登陆
*/
public boolean islogin(String username){
ActionContext actionContext=ActionContext.getContext();
Map session=actionContext.getSession();
Userlistener judge= (Userlistener) session.get("username");
if(judge!=null){
return true;
}else {
return false;
}
}
/*
注销
首先判断是否登陆
已经登陆--->移除Listener--->true
没有登陆--->false
*/
public boolean logoff(String username){
if(islogin(username)){
ActionContext actionContext=ActionContext.getContext();
Map session=actionContext.getSession();
session.remove(username);
return true;
}else {
return false;
}
}
/*
人数统计
返回Session中List的Size。
*/
public int returnNum(){
ActionContext actionContext=ActionContext.getContext();
Map session=actionContext.getSession();
ArrayList online= (ArrayList) session.get("online");
if(online==null){
online=new ArrayList();
}
return online.size();
}
/*
list返回
*/
public ArrayList returnlist(){
ActionContext actionContext=ActionContext.getContext();
Map session=actionContext.getSession();
ArrayList online= (ArrayList) session.get("online");
if(online==null){
online=new ArrayList();
}
return online;
}
}主页in.jsp
代码语言：javascript复制<%--
Created by IntelliJ IDEA.
User: Richard
Date: 2017/6/16
Time: 21:38
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Welcome</title>
</head>
<body>
<h1>WelCome to My Struts Page</h1>
<hr>
当前登录的用户:${param.username}<br>
<hr>
当前所有登陆的用户：
<table border=1 width=200>
<s:iterator value="#application.online" var="user">
<tr <s:if test="#user.odd"> style="background-color: dimgray" </s:if> >
<td><s:property value="#user.count"></s:property> </td>
<td><s:property value="#user"></s:property></td>
</tr>
</s:iterator>
</table>
<a href="login.jsp">注销</a>
</body>
</html>Action:
代码语言：javascript复制package UserBlock;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
import java.util.Map;
import java.util.logging.LogManager;
/**
* Created by Richard on 2017/6/16.
* 继承ActionSupport实现一个Action
* 登陆界面通过loginuser.action调用login()方法来处理数据
* login()方法中通过ActionContext调用Session对象，存入输入错误的数据
* 通过addActionMessage()方法向页面输出相关信息
* 注册页面通过reguser.action调用reg()方法来处理数据
*/
public class UserAction extends ActionSupport {
private String INDEX="index";
private String LOGIN="login";
private String REG="register";
private String username;
private String password;
private String compassword;
private UserDao user;
private UserManagment managment;
public String getCompassword() {
return compassword;
}
public void setCompassword(String compassword) {
this.compassword = compassword;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String login(){
try{
managment=new UserManagment();
user=new UserDao();
ArrayList result=user.up_select(username);
if(result.size()>0){
User aim= (User) result.get(0);
if(aim.getPassword().equals(password)){
/*登陆成功*/
managment.login(username);
return INDEX;
}else{
ActionContext applicton=ActionContext.getContext();
Map session=applicton.getSession();
int count;
if(session.get("count")==null){
count=0;
}else{
count= (int) session.get("count");
}
if(count>=3){
addActionMessage("错误次数过多");
count=0;
session.put("count",count);
return LOGIN;
}else{
count ;
addActionMessage("您输入的用户名或密码错误" count);
session.put("count",count);
return LOGIN;
}
}
}else{
addActionMessage("该用户不存在，已经跳转到注册页面");
return REG;
}
}catch (Exception e){
addActionError(e.getMessage());
System.out.println(e.getMessage());
e.printStackTrace();
return LOGIN;
}
}
public String reg(){
try{
managment=new UserManagment();
user=new UserDao();
ArrayList result=user.up_select(username);
if(result.size()>0)
{
addActionMessage("该用户已经存在");
return REG;
}
else{
if(user.insert(username,password)){
managment.login(username);
return INDEX;
}else{
addActionMessage("发生未知错误，请重试！");
return REG;
}
}
}catch (Exception e){
addActionError(e.getMessage());
return REG;
}
}
}Git源码
---->更新注销，注销的效果可以在列表中观察。
----->程序源码
