Eclipse啟動過程（源碼級剖析）

LibraryPKU 2013-12-12

展開全文

雙擊eclipse安裝目錄下的eclipse.exe運行后，會加載同一目錄下的eclipse.ini文件（對應RCP項目也是一樣，在RCP的安裝目錄下會有一個RCPName.ini文件）：

Java代碼

-startup
plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20110502
-product
org.eclipse.epp.package.rcp.product
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256M
-vmargs
-Dosgi.requiredJavaVersion=1.5
-Xms40m
-Xmx512m

這里要說一下,，Eclipse的JVM啟動的時候找JRE的順序是：
如果eclipse.ini中配置了-vm參數(shù),，那么則使用這個參數(shù)指定的JRE（jvm.dll庫路徑）；
否則,，查看eclipse安裝目錄下是否有JRE文件夾,，如果有的話就使用這個JRE；
否則,，去系統(tǒng)注冊表中查找安裝的JRE,，如果還找不到就報錯。

所以如果不想卸載掉其他的JDK的話,，可以有兩種方式：
直接把要使用的JRE文件夾拷貝到Eclipse目錄下
修改eclipse.ini文件，添加-vm參數(shù),，指定要運行的虛擬機的地址,，形如：
-vm
C:\Program Files\Java\jdk1.6.0_12\bin\..\jre\bin\client\jvm.dll

（在eclipse.ini文件中添加配置項時，有空格就換行,，不然會當成無效參數(shù)）

eclipse.ini文件中：
-startup 指定啟動的入口為：安裝目錄下plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
會加載該jar包中的org.eclipse.equinox.launcher.Main.class類并調(diào)用其main(String)完成app的啟動過程

通過一個Exception.printStackTrace()方法來看一下Eclipse的大概啟動過程：

點擊查看原始大小圖片

圖中是打印的狀態(tài)棧,，從下往上就是整個Eclipse（或者說RCP程序）的加載和啟動過程，一直到App的啟動,。
下面來通過源代碼,，具體說明：
從org.eclipse.equinox.launcher.Main這個類開始:

在Main這個類的main()方法中下一個斷的，調(diào)試狀態(tài)啟動Eclipse中的RCP程序就可以跟蹤這個RCP啟動的過程（Eclipse的過程也是類似的,，其實EclipseIDE就是一個巨型的RCP）：

Java代碼

public static void main(String[] args) {
int result = 0;
...
result = new Main().run(args);
...
}

然后看一下run()方法：

Java代碼

public int run(String[] args) {
...
basicRun(args);
...
}

主要實現(xiàn)就在basicRun()方法中：

Java代碼

protected void basicRun(String[] args) throws Exception {
//記錄啟動啟動時間
System.getProperties().put("eclipse.startTime", Long.toString(System.currentTimeMillis())); //$NON-NLS-1$
commands = args;
//處理Command參數(shù),，并根據(jù)Command參數(shù)設置默認屬性
String[] passThruArgs = processCommandLine(args);
if (!debug)
// debug can be specified as system property as well
debug = System.getProperty(PROP_DEBUG) != null;
setupVMProperties();//將VM參數(shù)寫入到System.Properties中
processConfiguration();//加載配置信息
getInstallLocation();//獲取安裝路徑,這里調(diào)用一下是為了確保InstallLocation被初始化
// locate boot plugin (may return -dev mode variations)
URL[] bootPath = getBootPath(bootLocation);//獲取啟動路徑列表
setupJNI(bootPath);//啟動JNIBridge，加載dll類庫
//檢查JDK版本
if (!checkVersion(System.getProperty("java.version"),
System.getProperty(PROP_REQUIRED_JAVA_VERSION)))
return;
//檢查配置信息
if (!checkConfigurationLocation(configurationLocation))
return;
setSecurityPolicy(bootPath);//設置安全策略
handleSplash(bootPath);//啟動閃屏,，就是Eclipse（或RCP啟動時IDE打開前帶有進度條的界面）
beforeFwkInvocation();
invokeFramework(passThruArgs, bootPath);//加載框架(前面的工作都是輔助,，這個才是加載框架的核心)
}

下面針對其中的幾個重要方法進行說明：

processConfiguration：處理配置信息

Java代碼

private void processConfiguration() {
URL baseConfigurationLocation = null;
Properties baseConfiguration = null;
//在系統(tǒng)的配置文件中，鍵值對形如：
//osgi.configuration.area=file:/E:/eclipse-rcp-indigo-SR2-win32/eclipse/configuration/
if (System.getProperty(PROP_CONFIG_AREA) == null) {
String baseLocation = System.getProperty(PROP_BASE_CONFIG_AREA);
if (baseLocation != null)
baseConfigurationLocation = buildURL(baseLocation, true);
if (baseConfigurationLocation == null)
try {
//在并沒指定參數(shù)的情況下,，將會把Location指定到: 安裝目錄/configuration
baseConfigurationLocation = new URL(getInstallLocation(), CONFIG_DIR);
} catch (MalformedURLException e) {
// leave baseConfigurationLocation null
}
//加載目錄下的config.ini文件,對其文件中的鍵值對配置信息
baseConfiguration = loadConfiguration(baseConfigurationLocation);
... ...
}
Properties configuration = baseConfiguration;
if (configuration == null || !getConfigurationLocation().equals(baseConfigurationLocation))
configuration = loadConfiguration(getConfigurationLocation());
//把配置信息合并到System.getProperties()中
mergeProperties(System.getProperties(), configuration, null);
... ...

config.ini文件內(nèi)容（舉例）

Java代碼

#This configuration file was written by: org.eclipse.equinox.internal.frameworkadmin.equinox.EquinoxFwConfigFileParser
#Sun Feb 17 13:24:53 CST 2013
org.eclipse.update.reconcile=false
eclipse.p2.profile=epp.package.rcp
osgi.instance.area.default=@user.home/workspace
osgi.framework=file\:plugins/org.eclipse.osgi_3.7.2.v20120110-1415.jar
equinox.use.ds=true
eclipse.buildId=M20120208-0800
osgi.bundles=reference\:file\:org.eclipse.equinox.simpleconfigurator_1.0.200.v20110815-1438.jar@1\:start
org.eclipse.equinox.simpleconfigurator.configUrl=file\:org.eclipse.equinox.simpleconfigurator/bundles.info
eclipse.product=org.eclipse.platform.ide
osgi.splashPath=platform\:/base/plugins/org.eclipse.platform
osgi.framework.extensions=
osgi.bundles.defaultStartLevel=4
eclipse.application=org.eclipse.ui.ide.workbench
eclipse.p2.data.area=@config.dir/../p2/

getInstallLocation（）獲取當前安裝路徑

Java代碼

private URL getInstallLocation() {
if (installLocation != null)
return installLocation;
//從系統(tǒng)配置信息中獲取安裝路徑,，有的話就直接返回
String installArea = System.getProperty(PROP_INSTALL_AREA);
if (installArea != null) {
installLocation = buildURL(installArea, true);
System.getProperties().put(PROP_INSTALL_AREA, installLocation.toExternalForm());
return installLocation;
}
//如果沒有，則通過獲取main類包的路徑換算出安裝路徑
ProtectionDomain domain = Main.class.getProtectionDomain();
CodeSource source = null;
URL result = null;
source = domain.getCodeSource();
result = source.getLocation();
String path = decode(result.getFile());
... ...
installLocation = new URL(result.getProtocol(), result.getHost(), result.getPort(), path);
return installLocation;
}

getBootPath（）獲取啟動路徑列表

Java代碼

protected URL[] getBootPath(String base) throws IOException {
URL url = null;
if (base != null) {
url = buildURL(base, true);
} else {
// search in the root location
url = getInstallLocation();
String path = new File(url.getFile(), "plugins").toString();
path = searchFor(framework, path);
if (url.getProtocol().equals("file"))
url = new File(path).toURL();
else
url = new URL(url.getProtocol(), url.getHost(), url.getPort(), path);
}
//鍵值對,，形如：osgi.framework=file:/e:/eclipse/plugins/org.eclipse.osgi_3.7.2.v20120110-1415.jar
//指定osgi jar的路徑
if (System.getProperty(PROP_FRAMEWORK) == null)
System.getProperties().put(PROP_FRAMEWORK, url.toExternalForm());
//獲取啟動路徑列表
URL[] result = getDevPath(url);
return result;
}

setupJNI（）啟動JNIBridge,，加載dll類庫

Java代碼

private void setupJNI(URL[] defaultPath) {
String libPath = null;
/**
* 獲取--launcher.library的路徑, 形如：
* --launcher.library
* plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20110502
*/
if (library != null) {
File lib = new File(library);
if (lib.isDirectory()) {
libPath = searchFor("eclipse", lib.getAbsolutePath()); //$NON-NLS-1$
} else if (lib.exists()) {
libPath = lib.getAbsolutePath();
}
}
if (libPath == null) {
/**
* 根據(jù)OS、WS,、Arch等信息,，加載相應的本地文件(如，dll或so),。
*/
//find our fragment name
String fragmentOS = getOS();
String fragmentWS = getWS();
String fragmentArch = getArch();
libPath = getLibraryPath(getFragmentString(fragmentOS, fragmentWS, fragmentArch), defaultPath);
if (libPath == null && ws == null) {
// no ws was specified and we didn't find the default fragment, try an alternate ws
String alternateWS = getAlternateWS(fragmentWS);
libPath = getLibraryPath(getFragmentString(fragmentOS, alternateWS, fragmentArch), defaultPath);
if (libPath != null) {
System.getProperties().put(PROP_WS, alternateWS);
}
}
}
library = libPath;
if (library != null)
bridge = new JNIBridge(library);//并創(chuàng)建JNIBridge,，這個還有待研究
}

invokeFramework（）啟動Equinox框架

Java代碼

private void invokeFramework(String[] passThruArgs, URL[] bootPath) throws Exception {
//如果沒有指定ClassLoader，默認將boot設置為OSGi框架的ClassLoader的父類
String type = System.getProperty(PROP_FRAMEWORK_PARENT_CLASSLOADER,
System.getProperty(PROP_PARENT_CLASSLOADER, PARENT_CLASSLOADER_BOOT));
ClassLoader parent = null;
if (PARENT_CLASSLOADER_APP.equalsIgnoreCase(type))
parent = ClassLoader.getSystemClassLoader();
else if (PARENT_CLASSLOADER_EXT.equalsIgnoreCase(type)) {
ClassLoader appCL = ClassLoader.getSystemClassLoader();
if (appCL != null)
parent = appCL.getParent();
} else if (PARENT_CLASSLOADER_CURRENT.equalsIgnoreCase(type))
parent = this.getClass().getClassLoader();
//生成一個Equinox框架的StartupClassLoader,，（關于ClassLoader分層機制,，還有待研究）
URLClassLoader loader = new StartupClassLoader(bootPath, parent);
//通過該ClassLoader加載org.eclipse.core.runtime.adaptor.EclipseStarter類,，并調(diào)用其run方法
Class clazz = loader.loadClass(STARTER);
Method method = clazz.getDeclaredMethod("run", new Class[] {String[].class, Runnable.class});
try {
//將命令行參數(shù)及閃屏線程對象傳遞給run方法
method.invoke(clazz, new Object[] {passThruArgs, splashHandler});
} catch (InvocationTargetException e) {
}
}

接下來看一下EclipseStarter.run()

Java代碼

public static Object run(String[] args, Runnable endSplashHandler) throws Exception {
if (Profile.PROFILE && Profile.STARTUP)
Profile.logEnter("EclipseStarter.run()", null); //$NON-NLS-1$
... ...
try {
startup(args, endSplashHandler);
... ...
Object obj=run(null);
return obj;
} catch (Throwable e) {
... ...
} finally {... ...}
return null;
}

Java代碼

public static BundleContext startup(String[] args, Runnable endSplashHandler) throws Exception {
... ...
FrameworkProperties.initializeProperties();
processCommandLine(args);
LocationManager.initializeLocations();
loadConfigurationInfo();
finalizeProperties();
if (Profile.PROFILE)
Profile.initProps(); // catch any Profile properties set in eclipse.properties...
adaptor = createAdaptor();//建立適配器
framework = new Framework(adaptor);//創(chuàng)建Equinox框架
context = framework.getBundle(0).getBundleContext();
registerFrameworkShutdownHandlers();
publishSplashScreen(endSplashHandler);//
consoleMgr = ConsoleManager.startConsole(framework);//控制臺啟動，會有信息輸出
framework.launch();//啟動框架
Bundle[] startBundles = loadBasicBundles();//loading basic bundles
... ...
// set the framework start level to the ultimate value. This will actually start things
// running if they are persistently active.
setStartLevel(getStartLevel());//StartLevel set
// they should all be active by this time
ensureBundlesActive(startBundles);
return context;
}

先到這里,，有空繼續(xù)分析

Java代碼

/**
* Runs the application for which the platform was started. The platform
* must be running.
* <p>
* The given argument is passed to the application being run. If it is <code>null</code>
* then the command line arguments used in starting the platform, and not consumed
* by the platform code, are passed to the application as a <code>String[]</code>.
* </p>
* @param argument the argument passed to the application. May be <code>null</code>
* @return the result of running the application
* @throws Exception if anything goes wrong
*/
public static Object run(Object argument) throws Exception {
if (Profile.PROFILE && Profile.STARTUP)
Profile.logEnter("EclipseStarter.run(Object)()", null); //$NON-NLS-1$
if (!running)
throw new IllegalStateException(EclipseAdaptorMsg.ECLIPSE_STARTUP_NOT_RUNNING);
// if we are just initializing, do not run the application just return.
if (initialize)
return new Integer(0);
try {
if (appLauncher == null) {
boolean launchDefault = Boolean.valueOf(FrameworkProperties.getProperty(PROP_APPLICATION_LAUNCHDEFAULT, "true")).booleanValue(); //$NON-NLS-1$
// create the ApplicationLauncher and register it as a service
appLauncher = new EclipseAppLauncher(context, Boolean.valueOf(FrameworkProperties.getProperty(PROP_ALLOW_APPRELAUNCH)).booleanValue(), launchDefault, log);
appLauncherRegistration = context.registerService(ApplicationLauncher.class.getName(), appLauncher, null);
// must start the launcher AFTER service restration because this method
// blocks and runs the application on the current thread. This method
// will return only after the application has stopped.
return appLauncher.start(argument);
}
return appLauncher.reStart(argument);
} catch (Exception e) {
if (log != null && context != null) // context can be null if OSGi failed to launch (bug 151413)
logUnresolvedBundles(context.getBundles());
throw e;
}
}