得到cocoachina论坛上fysp和akira_cn的帮助，理清了游戏热更新的思路：
cocos2d-js 3.0 rc0对AssetsManager功能进行了完善增强，支持多线程下载、断点续传、文件压缩、更好的进度信息以及错误重试机制，实现游戏资源文件和脚本文件的热更新变的更加方便。
用cocos new MyGame -l js -d /directory/to/project方式新建一个测试项目，参考sample写的src/AssetsManager.js：
var __failCount = 0;var AssetsManagerLoaderScene = cc.Scene.extend({ _am:null, _progress:null, _percent:0, _percentByFile:0, run:function(){ if (!cc.sys.isNative) { this.loadGame(); return; } var layer = new cc.Layer(); this.addChild(layer); this._progress = new cc.LabelTTF.create("0%", "Arial", 12); this._progress.x = cc.winSize.width / 2; this._progress.y = cc.winSize.height / 2 + 50; layer.addChild(this._progress); // android: /data/data/com.huanle.magic/files/ var storagePath = (jsb.fileUtils ? jsb.fileUtils.getWritablePath() : "./"); this._am = new jsb.AssetsManager("res/project.manifest", storagePath); this._am.retain(); if (!this._am.getLocalManifest().isLoaded()) { cc.log("Fail to update assets, step skipped."); this.loadGame(); } else { var that = this; var listener = new cc.EventListenerAssetsManager(this._am, function(event) { switch (event.getEventCode()){ case cc.EventAssetsManager.ERROR_NO_LOCAL_MANIFEST: cc.log("No local manifest file found, skip assets update."); that.loadGame(); break; case cc.EventAssetsManager.UPDATE_PROGRESSION: that._percent = event.getPercent(); that._percentByFile = event.getPercentByFile(); cc.log(that._percent + "%"); var msg = event.getMessage(); if (msg) { cc.log(msg); } break; case cc.EventAssetsManager.ERROR_DOWNLOAD_MANIFEST: case cc.EventAssetsManager.ERROR_PARSE_MANIFEST: cc.log("Fail to download manifest file, update skipped."); that.loadGame(); break; case cc.EventAssetsManager.ALREADY_UP_TO_DATE: case cc.EventAssetsManager.UPDATE_FINISHED: cc.log("Update finished."); that.loadGame(); break; case cc.EventAssetsManager.UPDATE_FAILED: cc.log("Update failed. " + event.getMessage()); __failCount ++; if (__failCount < 5) { that._am.downloadFailedAssets(); } else { cc.log("Reach maximum fail count, exit update process"); __failCount = 0; that.loadGame(); } break; case cc.EventAssetsManager.ERROR_UPDATING: cc.log("Asset update error: " + event.getAssetId() + ", " + event.getMessage()); that.loadGame(); break; case cc.EventAssetsManager.ERROR_DECOMPRESS: cc.log(event.getMessage()); that.loadGame(); break; default: break; } }); cc.eventManager.addListener(listener, 1); this._am.update(); cc.director.runScene(this); } this.schedule(this.updateProgress, 0.5); }, loadGame:function(){ cc.loader.loadJs(["src/files.js"], function(err){ cc.loader.loadJs(jsFiles, function(err){ cc.director.runScene(new HelloWorldScene()); }); }); }, updateProgress:function(dt){ this._progress.string = "" + this._percent; }, onExit:function(){ cc.log("AssetsManager::onExit"); this._am.release(); this._super(); }});修改项目目录下的main.js：
cc.game.onStart = function(){ cc.view.setDesignResolutionSize(800, 450, cc.ResolutionPolicy.SHOW_ALL); cc.view.resizeWithBrowserSize(true); var scene = new AssetsManagerLoaderScene(); scene.run();};cc.game.run();修改项目目录下的project.json：
{ "project_type": "javascript", "debugMode" : 1, "showFPS" : true, "frameRate" : 60, "id" : "gameCanvas", "renderMode" : 0, "engineDir":"frameworks/cocos2d-html5", "modules" : ["cocos2d", "extensions"], "jsList" : [ "src/AssetsManager.js" ]}就留一个AssetsManager.js，其他的js都通过它来加载。
增加一个src/files.js，需要动态加载的js文件都写在jsFiles这个数组里，这样js文件有增加变化，这个files.js一并更新，方便动态加载：
var jsFiles = [ "src/app.js", "src/resource.js"];项目res目录增加一个project.manifest文件，AssetsManager.js里会用到：
{ "packageUrl" : "http://10.0.128.219/res", "remoteManifestUrl" : "http://10.0.128.219/res/project.manifest", "remoteVersionUrl" : "http://10.0.128.219/res/version.manifest", "version" : "1.0.0", "groupVersions" : { "1" : "1.0.0" }, "engineVersion" : "3.0 rc0", "searchPaths" : [ ]}这里主要配置服务端资源下载地址，具体字段说明，在下面服务端配置里说明。然后用cocos compile -p android编译打包成一个apk安装包，等配置好服务端更新资源安装测试。
需要建一个WEB服务器做下载用，在其WEB目录http://10.0.128.219/res（我的测试机），增加version.manifest文件：
{ "packageUrl" : "http://10.0.128.219/res", "remoteManifestUrl" : "http://10.0.128.219/res/project.manifest", "remoteVersionUrl" : "http://10.0.128.219/res/version.manifest", "version" : "1.0.0", "groupVersions" : { "1" : "1.0.1" }, "engineVersion" : "3.0 rc0"}测试发现，AssetsManager首先会下载version.manifest文件，如果有更新的版本，那么才会去下载project.manifest，然后下载其中描述的资源文件。
project.manifest如下：
{ "packageUrl" : "http://10.0.128.219/res", "remoteManifestUrl" : "http://10.0.128.219/res/project.manifest", "remoteVersionUrl" : "http://10.0.128.219/res/version.manifest", "version" : "1.0.0", "groupVersions" : { "1" : "1.0.1" }, "engineVersion" : "3.0 rc0", "assets" : { "update1" : { "path" : "src/app.zip", "md5" : "f6bf54e5a0d42c963cc5ae81bf9dc6c6", "compressed" : true, "group" : "1" } }, "searchPaths" : [ ]}写法和官方文档里不太一样，特别是有个groupVersions字段，这个字段来自fysp在cocoachina论坛回答其他网友问题写的示例，测试发现用来做增量更新很方便，后面再说明。其他字段的说明官方文档已经很详细了。
由于客户端本地project.manifest里groupVersions的版本信息比服务器端的低，所以AssetsManager会下载http://10.0.128.219/res/src/app.zip到手机的/data/data/org.cocos2dx.hellojavascript/files/src/app.zip，并且会自动解压，但不会删除压缩包本身。
建议用root过的android手机测试，否则/data/data是没有权限查看。运行客户端测试程序后用adb连接查看：
e:\>adb shellshell@android:/ $ susushell@android:/ # ls -l /data/data/org.cocos2dx.hellojavascript/files/src/ls -l /data/data/org.cocos2dx.hellojavascript/files/src/-rw-rw-rw- app_65 app_65 2228 2014-07-08 14:23 app.js-rw-rw-rw- app_65 app_65 1552 2014-07-08 14:23 app.zipshell@android:/ # ls -l /data/data/org.cocos2dx.hellojavascript/files/ls -l /data/data/org.cocos2dx.hellojavascript/files/-rw-rw-rw- app_65 app_65 553 2014-07-08 14:23 project.manifestdrwxrwxrwx app_65 app_65 2014-07-08 14:23 src-rw-rw-rw- app_65 app_65 307 2014-07-08 14:23 version.manifest用firefox调试连上手机，发现app.js资源地址是/data/data/org.cocos2dx.hellojavascript/files/src/app.js，而不是assets/src/app.js，实现了热更新：
修改服务端version.manifest：
{ "packageUrl" : "http://10.0.128.219/res", "remoteManifestUrl" : "http://10.0.128.219/res/project.manifest", "remoteVersionUrl" : "http://10.0.128.219/res/version.manifest", "version" : "1.0.0", "groupVersions" : { "1" : "1.0.1", "2" : "1.0.2" }, "engineVersion" : "3.0 rc0"}修改服务端project.manifest：
{ "packageUrl" : "http://10.0.128.219/res", "remoteManifestUrl" : "http://10.0.128.219/res/project.manifest", "remoteVersionUrl" : "http://10.0.128.219/res/version.manifest", "version" : "1.0.0", "groupVersions" : { "1" : "1.0.1", "2" : "1.0.2" }, "engineVersion" : "3.0 rc0", "assets" : { "update1" : { "path" : "src/app.zip", "md5" : "f6bf54e5a0d42c963cc5ae81bf9dc6c6", "compressed" : true, "group" : "1" }, "update2" : { "path" : "src/config.zip", "md5" : "5d59789090e4143166430b2cf7b313ff", "compressed" : true, "group" : "2" } }, "searchPaths" : [ ]}这时在android客户端测试，已经更新到update1的，只会下载update2的更新，而没有更新过的，会把update1和update2都下载下来。
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