如何用 javaweb来写在线聊天应用

写这个玩意儿就是想练练手， 用户需要登陆才能在线聊天，不要依赖数据库， 不需要数据库的操作， 所有的数据都是保存在内存中， 如果服务器一旦重启，数据就没有了；

登录界面：

聊天界面：

左侧是在线的用户列表， 右侧是聊天的内容， 内容的格式为 “作者 ： 内容”；

点击button可以发布聊天信息；

使用的是spring搭建的框架，基于tomcat的服务器；

web.xml的配置如下：

<?xml version="1.0" encoding="UTF-8"?> 
<web-app version="3.0"  
    xmlns="http://java.sun.com/xml/ns/javaee"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> 
  <display-name></display-name>     
  <welcome-file-list> 
    <welcome-file>index.htm</welcome-file> 
  </welcome-file-list> 
   
  <servlet> 
    <servlet-name>test</servlet-name> 
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 
    <load-on-startup>1</load-on-startup> 
    </servlet> 
 
    <servlet-mapping> 
    <servlet-name>test</servlet-name> 
    <url-pattern>*.htm</url-pattern> 
    </servlet-mapping> 
 
    <listener> 
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> 
    </listener> 
     
    <filter> 
        <filter-name>CharacterEncodingFilter</filter-name> 
        <filter-class>com.nono.Filter.CharacterEncodingFilter</filter-class> 
        <init-param> 
            <param-name>encoding</param-name> 
            <param-value>UTF-8</param-value> 
        </init-param> 
    </filter> 
     
    <filter>   
        <filter-name>SecurityServlet</filter-name>   
        <filter-class>com.nono.SecurityServlet</filter-class>   
    </filter>   
    <filter-mapping>   
        <filter-name>SecurityServlet</filter-name>   
        <url-pattern>*.htm</url-pattern>   
    </filter-mapping> 
     
 
    <!--  
        使用Spring中的过滤器解决在请求和应答中的中文乱码问题  
    <filter> 
        <filter-name>characterEncodingFilter</filter-name> 
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> 
        <init-param> 
            <param-name>encoding</param-name> 
            <param-value>utf-8</param-value> 
        </init-param> 
        <init-param> 
                强制转换编码(request和response均适用)  
            <param-name>ForceEncoding</param-name> 
            <param-value>true</param-value> 
        </init-param> 
    </filter> 
    --> 
    
    <context-param> 
        <param-name> 
        contextConfigLocation 
        </param-name> 
        <param-value> 
        /WEB-INF/test-servlet.xml 
        </param-value> 
    </context-param> 
</web-app> 

conteConfigLocation的配置为：

<?xml version="1.0" encoding="UTF-8" ?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" 
 xmlns:context="http://www.springframework.org/schema/context" 
 xmlns:aop="http://www.springframework.org/schema/aop" 
 xmlns:tx="http://www.springframework.org/schema/tx" 
 xmlns:mvc="http://www.springframework.org/schema/mvc" 
 xmlns:task="http://www.springframework.org/schema/task" 
 xsi:schemaLocation="http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
      http://www.springframework.org/schema/context 
      http://www.springframework.org/schema/context/spring-context-3.0.xsd 
      http://www.springframework.org/schema/tx 
      http://www.springframework.org/schema/tx/spring-tx-3.0.xsd 
      http://www.springframework.org/schema/aop 
      http://www.springframework.org/schema/aop/spring-aop-3.0.xsd 
      http://www.springframework.org/schema/mvc 
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd 
      http://www.springframework.org/schema/task 
      http://www.springframework.org/schema/task/spring-task-3.0.xsd"> 
     
 
    <context:annotation-config> </context:annotation-config> 
    <context:component-scan base-package="com.nono" > </context:component-scan> 
     
    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> 
        <property name="suffix"> 
            <value>.jsp</value> 
        </property> 
    </bean> 
</beans> 

整个项目的结构为一个主路由， 四个po层,  两个过滤器：

界面的用户列表和用户内容列表用了ajax刷新， 感觉不错的说：

<!-- 
    修改pageEncoding为 utf-8 
 --> 
<%@ page language="java" import="java.util.*"  pageEncoding="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>login</title> 
    <meta charset="utf-8"> 
    <link href="http://cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet"> 
    <script src="http://cdn.bootcss.com/jquery/1.9.0/jquery.js"></script> 
  </head> 
  <style> 
      html,body,.bg{ 
          height:100%; 
      } 
      .bg{ 
          background:url(imgs/bg.jpeg); 
      } 
  </style> 
  <body> 
        <div class="container-fuild bg"> 
            <div class="row"> 
                <div class="col-sm-4"> 
                    <div class="page-header"> 
                        <h2> 
                            list 
                        </h2> 
                        <ol id="list"> 
                            <li>name—</li> 
                            <li>name—</li> 
                            <li>name—</li> 
                            <li>name—</li> 
                        </ol> 
                    </div> 
                </div> 
                <div class="col-sm-8"> 
                        <h2> 
                            content 
                        </h2> 
                    <div id="con" class="page-header"> 
                      <p> 
                          <b>haha:</b> 
                          <big> 
                              say someting 
                          </big> 
                      </p> 
                      <p> 
                          <b>haha:</b> 
                          <big> 
                              say someting 
                          </big> 
                      </p> 
                    </div> 
                    <form> 
                      <div class="form-group"> 
                        <label for="text">enter text</label> 
                        <input type="text" id="answer" class="form-control" id="text" placeholder="text"> 
                      </div> 
                      <button type="button" id="sb" class="btn btn-default">Submit</button> 
                    </form> 
                </div> 
            </div> 
        </div> 
        <script> 
            $("#sb").click(function() { 
                $.post("chat.htm", "content="+ $("#answer").val(), function(data) { 
                    console.log(data); 
                }); 
            }); 
             
            function Get(url , el, fn) { 
                this.post = function() { 
                    $.post(url, function(data) { 
                        data = JSON.parse(data); 
                        var html = ""; 
                        $.each(data,function(i, e) { 
                            html += fn(i,e); 
                        }); 
                        $(el).html( html ); 
                    }); 
                }; 
            }; 
             
            (function() { 
             
                var list = new Get("getList.htm", "#list", function(i, e) { 
                    return  "<li>" + e.name + "</li>"; 
                }); 
                 
                var content =  new Get("getContent.htm", "#con", function(i, e) { 
                    return "<p><b>"+ e.name +" : </b><big>"+ e.content +"</big></p>"; 
                }); 
                 
                setInterval(function() { 
                    list.post(); 
                    content.post(); 
                },1000); 
                 
            })(); 
        </script> 
  </body> 
</html> 

权限控制的话我们可以用到fileter：

package com.nono; 
 
import java.io.IOException; 
import javax.servlet.Filter; 
import javax.servlet.FilterChain; 
import javax.servlet.FilterConfig; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRequest; 
import javax.servlet.ServletResponse; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 
 
import com.nono.po.User; 
 
public class SecurityServlet extends HttpServlet implements Filter { 
    private static final long serialVersionUID = 1L; 
 
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException { 
           HttpServletRequest request=(HttpServletRequest)arg0;    
           HttpServletResponse response  =(HttpServletResponse) arg1;     
           HttpSession session = request.getSession(); 
           User user = (User) session.getAttribute("user"); 
           String url=request.getRequestURI();    
           //如果用户信息不是空的， 或者要访问的是登陆的界面(get,post的方式包含了login字符串); 
           if( user!=null  || url.indexOf("login")>-1 ) { 
               arg2.doFilter(arg0, arg1);    
               return; 
           }else{ 
               //余下的全跳到登陆界面 
               response.sendRedirect(request.getContextPath() + "/login.htm"); 
               return; 
           } 
    } 
    public void init(FilterConfig arg0) throws ServletException { 
    } 
 
} 

 路由控制和服务放到了一起， 因为权限控制使用过滤器处理， 所以在路由里面我们就不用关心用户的消息， 只要处理业务逻辑就好了：

package com.nono.Controller; 
 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.Vector; 
 
import javax.jms.Session; 
import javax.print.DocFlavor.STRING; 
import javax.print.attribute.HashAttributeSet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 
 
import net.sf.json.JSONArray; 
 
import org.omg.CORBA.PUBLIC_MEMBER; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestMethod; 
import org.springframework.web.bind.annotation.ResponseBody; 
 
import com.nono.po.Content; 
import com.nono.po.Contents; 
import com.nono.po.User; 
import com.nono.po.Users; 
 
@Controller 
public class MainController { 
    //用户和用户组; 
    @Autowired 
    Users users; 
     
    @Autowired 
    Contents contents; 
     
    @RequestMapping(value="login", method=RequestMethod.GET) 
    public String login (HttpServletRequest request) { 
        return "login"; 
    } 
 
     
    @RequestMapping(value="login", method=RequestMethod.POST) 
    public String loginPOST ( HttpServletRequest request, HttpServletResponse response ) { 
         
        String string = "login"; 
        String name = (String) request.getParameter("name"); 
        Boolean flag = true; 
        //如果名字不是空的话; 
        if( !name.equals("") ) { 
            Vector vector = users.getList(); 
            for(int i=0; i< vector.size(); i++) { 
                User user = (User) vector.elementAt(i); 
                if( user.getName().equals( name ) ) { 
                    flag = false; 
                }; 
            }; 
        }; 
         
        //用户名不存在 
        if( flag ) { 
            User user = new User(); 
            user.setName( name ); 
            HttpSession session = request.getSession(true); 
            //设置Session的过期时间为10分钟 
            session.setMaxInactiveInterval(600); 
            //设置seesion中的用户信息; 
            session.setAttribute("user", user); 
            //添加用户; 
            users.addUser( user ); 
             
            //加入的提示; 
            Content content = new Content(); 
            content.setName( name ); 
            content.setContent( "enter the chat room!" ); 
            contents.addContent( content  ); 
             
            string = "chat"; 
            return string; 
        }else{ 
            //用户名已经存在 
            request.setAttribute("info", "用户名已经存在1"); 
            string = "login"; 
            return string; 
        } 
    } 
     
    @RequestMapping(value="chat", method=RequestMethod.GET) 
    public String main (HttpServletRequest request) { 
        String string = "chat"; 
        return string; 
    } 
     
    @RequestMapping(value="chat", method=RequestMethod.POST) 
    @ResponseBody 
    public String chat(HttpServletRequest request) { 
        String string = (String) request.getParameter("content"); 
        HttpSession session = request.getSession(); 
        //设置seesion中的用户信息; 
        User user = (User) session.getAttribute("user"); 
        String name = user.getName(); 
        Content content = new Content(); 
        content.setName( name ); 
        content.setContent( string ); 
        contents.addContent( content  ); 
        return "true"; 
    } 
     
    @RequestMapping(value="getList", method=RequestMethod.POST, produces = "text/html;charset=UTF-8") 
    @ResponseBody 
    public String getList( HttpServletRequest request) { 
        return JSONArray.fromObject( users.getList() ).toString(); 
    } 
     
    @RequestMapping(value="getContent", method=RequestMethod.POST, produces = "text/html;charset=UTF-8") 
    @ResponseBody 
    public String getArrayList() { 
        ArrayList list = (ArrayList) contents.getContents(); 
        ArrayList result = new ArrayList(); 
        for( int i= 0; i< list.size(); i++ ) { 
            HashMap<String,String> hashMap = new HashMap(); 
            hashMap.put("name", ((Content)list.get(i)).getName()); 
            hashMap.put("content", ((Content)list.get(i)).getContent()); 
            result.add( hashMap ); 
        }; 
        return JSONArray.fromObject( result ).toString(); 
    } 
     
} 

有哪位大神告诉我为什么中文各种乱码， 在界面中的utf-8也设置， @ResponseBody的也设置了， 还是乱码， encodeURIComponent过的也是乱码， 坑爹啊；