DWR实现聊天室demo

package dwrpush; import java.util.Collection; import javax.servlet.http.HttpSession; import org.directwebremoting.ScriptBuffer; import org.directwebremoting.ScriptSession; import org.directwebremoting.WebContext; import org.directwebremoting.WebContextFactory; public class SendPush { /** * 推送消息 代码大意请参见说明3 * * @param msg */ public void send(String channel, String msg, String to) { try { WebContext context = WebContextFactory.get(); // 获取访问这个页面的所有session,既访问这个页面的所有用户 Collection<ScriptSession> sessions = context .getScriptSessionsByPage("/dwrpush/index.jsp"); ScriptSession myScSession = context.getScriptSession(); if ((msg == null || "".equals(msg)) || (channel == null || "".equals(channel))) { return; } HttpSession httpSession = context.getSession(); /* * 因为每次刷新页面都要生成新的会话,所以要记录上次生成的会话,以便在每次刷新页面或退出时, 让上次的会话失效. * 由于在分布式环境中要求放入作用域的对应要implements Serializable. * 但ScriptSession没有继承Serializable,其实现类也没有实现Serializable. * 所以这里用hashCode进行标识一个会话. */ httpSession.setAttribute("scriptSession", myScSession.hashCode()); User user = (User) httpSession.getAttribute("user"); if (user == null) { return; } if ((User) myScSession.getAttribute("user") == null) { myScSession.setAttribute("user", user); } Chat chat = new Chat(); chat.setType(channel); chat.setMsg(" " + msg); chat.setSender(user.getUsername()); ScriptBuffer buffer = new ScriptBuffer(); buffer.appendScript("Chat.receive("); buffer.appendData(chat); buffer.appendScript(")"); boolean existTo = false;// 用于私聊,标识要聊天的对象是否存在 for (ScriptSession s : sessions) {// 循环所有的人,向其发送消息 User u = (User) s.getAttribute("user"); if (u != null && !chat.getMsg().matches("\\s+")) { if ("0".equals(channel) && (s == myScSession || u.getRoomName().equals( user.getRoomName()))) {// 发送当前角色所在场景的信息 s.addScript(buffer); } else if ("1".equals(channel)) {// 发送自己班级的信息 if (!"".equals(user.getClazz()) && (u.getClazz().equals(user.getClazz()))) {// 班级默认是空串,所以要排除 s.addScript(buffer);// 详见说明2 } else if (s == myScSession && "".equals(user.getClazz())) {// 表示没有加入班级 chat.setSender("系统"); chat.setMsg(" 还没有加入班级"); chat.setState(-1); ScriptBuffer b = new ScriptBuffer(); b.appendScript("Chat.receive("); b.appendData(chat); b.appendScript(")"); myScSession.addScript(b); return; } } else if ("2".equals(channel)) {// 发送自己社团的信息 if (!"".equals(user.getAsso()) && (u.getAsso().equals(user.getAsso()))) { s.addScript(buffer); } else if (s == myScSession && "".equals(user.getAsso())) {// 表示没有加入社团 chat.setSender("系统"); chat.setMsg(" 还没有加入社团"); chat.setState(-1); ScriptBuffer b = new ScriptBuffer(); b.appendScript("Chat.receive("); b.appendData(chat); b.appendScript(")"); myScSession.addScript(b); return; } } else if ("3".equals(channel)) {// 世界 s.addScript(buffer); } else if ("4".equals(channel)) {// 私聊 if (user.getUsername().equals(to)) {// 如果是对自己聊天 chat.setMsg(" 不能对自己聊天"); chat.setSender("系统"); chat.setState(-1); ScriptBuffer b = new ScriptBuffer(); b.appendScript("Chat.receive("); b.appendData(chat); b.appendScript(")"); myScSession.addScript(b); return; } if (u.getUsername().equals(to) && s != myScSession) {// 向对方发送私聊信息 chat.setSender(user.getUsername() + "对您说"); ScriptBuffer b = new ScriptBuffer(); b.appendScript("Chat.receive("); b.appendData(chat); b.appendScript(")"); s.addScript(b); existTo = true; // 经过测试即,使找到私聊的对象,也不能return,必须继续循环完才能将消息推送出去. // return; } } else if ("5".equals(channel)) {// 系统 s.addScript(buffer); } } } if ("4".equals(channel)) { if (!existTo) {// 如果不存在私聊对象 chat.setMsg(" 角色不存在或不在线"); chat.setSender("系统"); buffer = new ScriptBuffer(); buffer.appendScript("Chat.receive("); buffer.appendData(chat); buffer.appendScript(")"); myScSession.addScript(buffer); } else {// 存在则还要向自己发送信息 chat.setSender("您对" + to + "说"); ScriptBuffer b = new ScriptBuffer(); b.appendScript("Chat.receive("); b.appendData(chat); b.appendScript(")"); myScSession.addScript(b); } } } catch (Exception e) { e.printStackTrace(); } } /** * 当刷新页面或退出时,调用此方法,以便清除多余的session. 见说明1 */ public void exitGame() { try { System.out.println("++++++"); WebContext context = WebContextFactory.get(); HttpSession httpSession = context.getSession(); Integer myScSession = (Integer) httpSession .getAttribute("scriptSession"); if (myScSession != null) { Collection<ScriptSession> sessions = context .getScriptSessionsByPage("/dwrpush/index.jsp"); for (ScriptSession s : sessions) { if (s.hashCode() == myScSession) { s.invalidate(); return; } } } } catch (Exception e) { e.printStackTrace(); } } }