DWR 消息推送

DWR 消息推送

web.xml

<?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"> <servlet>
<servlet-name>spring3</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/conf/spring3-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring3</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>spring3</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<filter>
<description>字符集过滤器（前台往后台提交数据编码）</description>
<filter-name>encodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<description>字符集编码</description>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>

要显示推送消息的页面加上

<!-- dwr start -->
<script type="text/javascript" src="$path/dwr/engine.js"></script>
<script type="text/javascript" src="$path/dwr/util.js"></script>
<script type="text/javascript" src="$path/dwr/interface/directController.js"></script>
<script type="text/javascript">
$(document).ready(function() {
//这个方法用来启动该页面的ReverseAjax功能
dwr.engine.setActiveReverseAjax(true);
//设置在页面关闭时，通知服务端销毁会话
dwr.engine.setNotifyServerOnPageUnload(true);
//设置DWR调用服务出错时，不打印(alert)调试信息
dwr.engine.setErrorHandler(function() {
//
});
onPageLoad();
})
function onPageLoad() {
//这是随机生成的一个类似于id的传到后台
var a = Math.round(Math.random()*100);
directController.onPageLoad(a);
}
function showMessage(autoMessage) {
//显示推送的消息
document.getElementById('dwr_message').innerHTML = autoMessage;
}
</script>
<-- dwr end -->

这是管理员的页面，填写要推送的消息

//先加载DWR
window.onload = function(){
onPageLoad();
dwr.engine.setActiveReverseAjax(true);
dwr.engine.setNotifyServerOnPageUnload(true);
}

function send(){
//获取消息
var message = $("#dwr_mess").val();
$.ajax({
url : "sendmessage_dwr?message="+message,
dataType : "json",
type : "POST",
success : function(data) {
alert("成功");
},
});
}

Spring配置文件 添加内容

xmlns:dwr="http://www.directwebremoting.org/schema/spring-dwr" http://www.directwebremoting.org/schema/spring-dwr http://www.directwebremoting.org/schema/spring-dwr-3.0.xsd

<!-- 处理静态文件请求，对静态文件不进行 Dispatcher -->
<mvc:resources mapping="/dwr/**" location="/dwr/" />

<!-- 要求dwr在spring容器中检查拥有@RemoteProxy 和 @RemoteMethod注解的类。注意它不会去检查Spring容器之外的类。 -->
<bean id="simpleUrlHandlerMapping"
class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter" />
<dwr:annotation-config id="dwr" />     <!-- 要求DWR将util.js和engine.js映射到dwrController -->
<dwr:url-mapping />    <!-- 定义dwr -->
<dwr:controller id="dwrController" debug="true">
<dwr:config-param name="allowScriptTagRemoting"
value="true" />
<dwr:config-param name="crossDomainSessionSecurity"
value="false" />
<dwr:config-param name="classes" value="java.lang.Object" />
<dwr:config-param name="activeReverseAjaxEnabled"
value="true" />        <!-- script session 的超时设置 默认值：1800000(30分钟) -->
<dwr:config-param name="scriptSessionTimeout" value="3600000" />
<dwr:config-param name="initApplicationScopeCreatorsAtStartup"
value="true" />
<dwr:config-param name="org.directwebremoting.extend.ScriptSessionManager"
value="com.cq.module.dwr_LiuTang.util.DWRScriptSessionManager" />
</dwr:controller>    <!-- DWR配置 -->

这是DWR的3个固定的类

public class DWRScriptSessionListener implements ScriptSessionListener {
// 维护一个Map
// key为session的Id，
// value为ScriptSession对象
public static final Map<String, ScriptSession> scriptSessionMap = new HashMap<String, ScriptSession>();

/**
* ScriptSession创建事件
*/
public void sessionCreated(ScriptSessionEvent event) {
WebContext webContext = WebContextFactory.get();
HttpSession session = webContext.getSession();
ScriptSession scriptSession = event.getSession();
scriptSessionMap.put(session.getId(), scriptSession);
// 添加 scriptSession
System.out.println("session: " + session.getId() + " scriptSess ion: "
+ scriptSession.getId() + "is created!");
}

/**
* ScriptSession销毁事件
*/
public void sessionDestroyed(ScriptSessionEvent event) {
WebContext webContext = WebContextFactory.get();
HttpSession session = webContext.getSession();

ScriptSession scriptSession = scriptSessionMap.remove(session.getId());
// 移除scriptSession
System.out.println("session: " + session.getId() + " scriptSess ion: "
+ scriptSession.getId() + "is destroyed!");
}

/**
* 获取所有ScriptSession
*/
public static Collection<ScriptSession> getScriptSessions() {
return scriptSessionMap.values();
}
}

public class DWRScriptSessionManager extends DefaultScriptSessionManager {
public DWRScriptSessionManager() {
// 绑定一个ScriptSession增加销毁事件的监听器
this.addScriptSessionListener(new DWRScriptSessionListener());
}
}

public class SendMessageAutoUtil {
// 消息推送 指定某个客户端的页面显示
public static void sendMessageAuto(String userid, String message,
String showScriptMethod) {
final String yhId = userid;
// 页面标志
final String autoMessage = message;// 返回的数据
final String autoShowScriptMethod = showScriptMethod;// 返回页面要调用的JS方法
// 执行推送
Browser.withAllSessionsFiltered(new ScriptSessionFilter() {
public boolean match(ScriptSession scriptSession) {
String yhid = (String) scriptSession.getAttribute("yhId");
if (yhid != null) {
return yhId.equals(yhid);
} else {
return false;
}
}
}, new Runnable() {
private ScriptBuffer script = new ScriptBuffer();

public void run() {
// 设置要调用的 js及参数
script.appendCall(autoShowScriptMethod, autoMessage);
// 得到过滤之后的ScriptSession
Collection<ScriptSession> sessions = Browser
.getTargetSessions();
// 遍历每一个ScriptSession
for (ScriptSession scriptSession : sessions) {
scriptSession.addScript(script);
}
}
});
// 注意这里调用了有filter功能的方法
}

//  有错误
// 消息推送 指定某个客户端的页面显示 此方法是把要推送的ID放到集合
public static void sendMessageListAuto(List targetYhidList, String stuxx,
String showScriptMethod) {
final List targetIdList = targetYhidList;
final String autoMessage = stuxx;
final String autoShowScriptMethod = showScriptMethod;
// 执行推送
Browser.withAllSessionsFiltered(new ScriptSessionFilter() {
public boolean match(ScriptSession scriptSession) {
String yhid = (String) scriptSession.getAttribute("yhId");
if (yhid != null && targetIdList.contains(yhid)) {
// return yhid.equals(yhId);
targetIdList.remove(yhid);// 如果找到了，说明将被推送，所以不用再
// 处理,剩下的都是要被处理的
return true;
} else {
return false;
}
}
}, new Runnable() {
private ScriptBuffer script = new ScriptBuffer();

public void run() {
// 设置要调用的 js及参数
script.appendCall(autoShowScriptMethod, autoMessage);
// 得到过滤之后的ScriptSession
Collection<ScriptSession> sessions = Browser
.getTargetSessions();
// 遍历每一个ScriptSession
for (ScriptSession scriptSession : sessions) {
scriptSession.addScript(script);
}
}

});
// 注意这里调用了有filter功能的方法
}
}

这是我自己写的一个存储id的工具，dwr的那套我看不懂（因为用户不多，所以没考虑并发）

public class IdsList {

private static Map<String,Date> maps = new HashMap<String, Date>();

public static void set(String id){
maps.put(id, new Date());
}

public static List<String> get(){
List<String> result = new ArrayList<String>();
List<String> mid = new ArrayList<String>();
long now = new Date().getTime();
for(String key:maps.keySet()){
if((now - maps.get(key).getTime()) > 1800000){   //如果时间超过30分钟
mid.add(key);
}else{
result.add(key);
}
}
//删除超过30分钟的数据
for(String key:mid){
maps.remove(key);
}
return result;
}
}

这是2个controller

/**
这个对应要显示的页面，  获取随机id
*/
@Controller
@RemoteProxy(name = "directController")
public class DirectController {

@RemoteMethod
public void onPageLoad(final String yhId) {
ScriptSession scriptSession = WebContextFactory.get()
.getScriptSession();
scriptSession.setAttribute("yhId", yhId);
IdsList.set(yhId);
}

}

/**
* 发送消息
* @author LT
*/
@Controller
public class MessageDwrController {

@RequestMapping("sendmessage_dwr")
@ResponseBody
public Boolean aa(String message){
List<String> ids = IdsList.get();
for(int i=0;i<ids.size();i++){
SendMessageAutoUtil.sendMessageAuto(ids.get(i), message, "showMessage");
}
return true;
}
}

欢迎大家指错，谢谢！ （自己添加一个DWR的jar包）