Applet + Javascript 替代 comet 轮回 pull
对于不熟悉flex的童鞋，要做一些像聊天等交互性功能，用applet + js也是很容易实现的——而且，跨浏览器，js也容易操作dom进行页面内容展示。1. 建立一个工程，compiler level设置1.3
2. 找到jre lib 下的plugin.jar，导入路径
3. 写一个比较通用的socket client applet，暴露一些主要方法，比如jsFunCall connect close send，connect方法里开启一个domain thread负责接收处理数据（最好是以接口形式）
话说actionscript那种socket方法回调那是一个简单啊！java线程小麻烦了点。
package com.cisee.appletjs;import java.applet.Applet;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.Socket;import java.util.Random;import netscape.javascript.JSException;import netscape.javascript.JSObject;public abstract class JsApplet extends Applet {/** Socket */private Socket sock = null;/** Input Stream */private InputStream is = null;/** Output Stream */private OutputStream os = null;private final int port = 12800;private final String host = "127.0.0.1";/** win JSObject */protected JSObject win = null;/** doc JSObject */protected JSObject doc = null;/** Is connected? */protected boolean connected = false;Thread reviever;String userid;String toUserid;protected String getInfo() {return "Cisee Applet Javascript Interpretor Operation";}public void init() {logMsg("Init..");userid = System.currentTimeMillis() + "_" + new Random().nextInt(100);}public void destroy() {closeConnect();}/** * JS Object*/protected JSObject getWin() {if (win == null)win = JSObject.getWindow(this);return win;}protected JSObject getDoc() {if (doc == null)doc = (JSObject) getWin().getMember("document");return doc;}public abstract void processMessage(final String msg);/** * Send message to server. * @param msg message that will be sent. */void sendToServer(final String msg) {if (connected) {try {logMsg(msg);os.write((msg).getBytes());os.write("\r\n".getBytes());os.flush();} catch (IOException e) {logMsg("Stream write error.", e);}} else {wincall("warn_notconnected", null);}}/** * Close connection. */void closeConnect() {if(reviever != null)reviever.stop();connected = false;if (sock != null) {try {sock.close();} catch (IOException e) {e.printStackTrace();}sock = null;}}/** * Call function of outside explorer's script. * @param function function name. * @param param Parameter values. */protected void wincall(final String function, final Object[] param) {Object[] realParam = param == null?new Object:param;try {getWin().call(function, realParam);} catch (JSException e) {callAlert("function : "+ function+ "(arg*"+ realParam.length+ ") is exist?");}}/** * Call alert function of outside explorer's script. * @param msg Message. */protected void callAlert(final String msg) {try {getWin().call("alert", new String[] { msg });} catch (JSException e1) {e1.printStackTrace();}}/** * Log message when debug is true. * @param msg Message. */protected void logMsg(final String msg) {System.out.println(msg);}/** * Log message when debug is true. * @param msg Message. * @param e Exception. */protected void logMsg(final String msg, final Throwable e) {System.out.println(msg + "\r\nCause : " + e.getMessage());e.printStackTrace();}/** * Connect to server. */public void connect() {if (connected) {return;}logMsg("Connect to server..."); try {// Conect to server..sock = new Socket(host, port);is = sock.getInputStream();os = sock.getOutputStream();connected = true;// Thread that receive messages.reviever = new Thread() {public void run() {try {while (sock != null && !sock.isClosed()) {if (is.available() != 0) {byte[] buf = new byte; is.read(buf); String line = new String(buf).trim();processMessage(line);}}} catch (IOException e) {logMsg("Error..", e);} finally {if (connected) {closeConnect();wincall("warn_connect_failed", null);}}}};reviever.setDaemon(true);reviever.start();} catch (IOException e) {e.printStackTrace();}}public void sendMsg(final String toId, final String msg) {try {// TODOsendToServer(msg);} catch (Exception e1) {logMsg("Error in sendMsg", e1);}}public void quit() {try {sendToServer("quit");closeConnect();wincall("applet_quit", null);} catch (Exception e) {logMsg("Error in quit", e);}}public boolean isConnected() {return connected;}}
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