程序包 io.esastack.cabin.container.service.loader

类 JavaAgentClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

io.esastack.cabin.container.service.loader.AbstractClassLoader

io.esastack.cabin.container.service.loader.JavaAgentClassLoader

所有已实现的接口:

Closeable, AutoCloseable

public class JavaAgentClassLoader
extends AbstractClassLoader

When the agent classes are loaded? while jvm define a class, it will check if any agents are provided to instrument the class, and the enhanced class byte code are used to create the new Class Object with the original classloader, while the weaved-in code is executed, the agent classes are load by the original classloader. Default handling of JVM? By default, java agent jar URLs will be included in the SystemClassLoader classpath, if cabin is not used, no matter using java -jar or java -cp to setup a program, all the agent urls and biz urls are in the SystemClassloader. Handling of Cabin? + While cabin is used, agent urls can be handled as biz urls, and there is no isolation between agent and biz urls. + Cabin use JavaAgentClassLoader to load agent classes for isolation. + Agent classes can load classes from biz: default imported classes(spring/jedis/slf4j, etc.), provided classes. + Agent Classes can load classes from lib: exported classes, provided classes. + Biz and lib can load classes from agent: classes used in weaved-in code.

字段概要

从类继承的字段 io.esastack.cabin.container.service.loader.AbstractClassLoader

classLoaderService, moduleName, sharedClassService, sharedResourceService

构造器概要

构造器

构造器	说明
JavaAgentClassLoader(URL agentUrl)

方法概要

修饰符和类型	方法	说明
URL	getAgentUrl()
protected URL	getResource0(String name)	Pay attention to the priority of finding resource: jdk, exported, biz
protected Enumeration<URL>	getResources0(String name)	Pay attention to the priority of finding resource: jdk, exported, biz
protected Class<?>	loadClass0(String name, boolean resolve)	Why we need to load class from Biz and Libs?

从类继承的方法 io.esastack.cabin.container.service.loader.AbstractClassLoader

debugClassLoadMessage, getBizResource, getBizResources, getExportResource, getExportResources, getJavaAgentResource, getJavaAgentResources, getJdkResource, getJdkResources, getLocalResource, getLocalResources, getModuleName, getResource, getResources, loadAgentClass, loadBizClass, loadCabinClass, loadClass, loadClassFromClasspath, loadFromRecords, loadImportClassFromBiz, loadJdkClass, loadLocalClass, loadSharedClass, shouldImportClassFromBiz

从类继承的方法 java.net.URLClassLoader

addURL, close, definePackage, findClass, findResource, findResources, getPermissions, getResourceAsStream, getURLs, newInstance, newInstance

从类继承的方法 java.security.SecureClassLoader

defineClass, defineClass

从类继承的方法 java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

JavaAgentClassLoader

public JavaAgentClassLoader(URL agentUrl)

方法详细资料

getAgentUrl

public URL getAgentUrl()

loadClass0

protected Class<?> loadClass0(String name,
                              boolean resolve)
                       throws CabinLoaderException

Why we need to load class from Biz and Libs? The Pre-Main class would be loaded by SystemClassLoader while the Jvm started; If some code are weaved in, the code may include another Class in the agent jar and this class may depend on some biz/module classes, this class would be loaded by agent classloader, so agent classloader must delegate class loading to biz and module classloader too; Because the agent implementation may dependency some provided jars which is provided by users; In normal setup way, these jars will loaded by AppClassloader, same classloader of agent jars.

指定者:

loadClass0 在类中 AbstractClassLoader

抛出:

CabinLoaderException

getResources0

protected Enumeration<URL> getResources0(String name)
                                  throws IOException

从类复制的说明: AbstractClassLoader

Pay attention to the priority of finding resource: jdk, exported, biz

指定者:

getResources0 在类中 AbstractClassLoader

抛出:

IOException

getResource0

protected URL getResource0(String name)

从类复制的说明: AbstractClassLoader

Pay attention to the priority of finding resource: jdk, exported, biz

指定者:

getResource0 在类中 AbstractClassLoader