classloader === > 查看classloader的继承树，urls，类加载信息 `classloader` 命令将 JVM 中所有的classloader的信息统计出来，并可以展示继承树，urls等。 可以让指定的classloader去getResources，打印出所有查找到的resources的url。对于`ResourceNotFoundException`比较有用。 ### 参数说明 |参数名称|参数说明| |---:|:---| |[l]|按类加载实例进行统计| |[t]|打印所有ClassLoader的继承树| |[a]|列出所有ClassLoader加载的类，请谨慎使用| |`[c:]`|ClassLoader的hashcode| |`[c: r:]`|用ClassLoader去查找resource| ### 使用参考 * 按类加载类型查看统计信息 ```s $ classloader name numberOfInstances loadedCountTotal com.taobao.pandora.service.loader.ModuleClassLoader 29 11659 com.taobao.pandora.boot.loader.ReLaunchURLClassLoader 1 5308 BootstrapClassLoader 1 3711 com.taobao.arthas.agent.ArthasClassloader 2 2825 sun.reflect.DelegatingClassLoader 332 332 java.net.URLClassLoader 1 285 sun.misc.Launcher$AppClassLoader 1 77 sun.misc.Launcher$ExtClassLoader 1 46 com.alibaba.fastjson.util.ASMClassLoader 2 3 org.jvnet.hk2.internal.DelegatingClassLoader 2 2 sun.reflect.misc.MethodUtil 1 1 Affect(row-cnt:11) cost in 66 ms. ``` * 按类加载实例查看统计信息 ```sh $ classloader -l name loadedCount hash parent BootstrapClassLoader 3711 null null com.alibaba.fastjson.util.ASMClassLoader@3bbaa1b8 2 3bbaa1b8 monitor's ModuleClassLoader com.alibaba.fastjson.util.ASMClassLoader@5e255d0b 1 5e255d0b eagleeye-core's ModuleClassLoader com.taobao.arthas.agent.ArthasClassloader@4fa2d7e6 1795 4fa2d7e6 sun.misc.Launcher$ExtClassLoader@a38d7a3 com.taobao.arthas.agent.ArthasClassloader@522400c2 1033 522400c2 sun.misc.Launcher$ExtClassLoader@a38d7a3 com.taobao.pandora.boot.loader.ReLaunchURLClassLoader@1817d444 5308 1817d444 sun.misc.Launcher$AppClassLoader@14dad5dc tbsession's ModuleClassLoader 285 609cd4d8 null pandora-qos-service's ModuleClassLoader 267 2f8dad04 null pandora-framework's ModuleClassLoader 78 4009e306 null filesync-client's ModuleClassLoader 4 4b8ee4de null rocketmq-client's ModuleClassLoader 431 247bddad null eagleeye-core's ModuleClassLoader 451 1ba9117e null alimonitor-jmonitor's ModuleClassLoader 134 22fcf7ab null metaq-client's ModuleClassLoader 35 41a2befb null hsf-mock's ModuleClassLoader 3 2002fc1d null monitor's ModuleClassLoader 1427 131ef10 null spas-sdk-service's ModuleClassLoader 7 10d307f1 null vipserver-client's ModuleClassLoader 137 7a419da4 null metrics's ModuleClassLoader 146 696da30b null mtop-uncenter's ModuleClassLoader 922 79d8407f null spas-sdk-client's ModuleClassLoader 235 4944252c null live-profiler-pandora's ModuleClassLoader 1 6913c1fb null notify-tr-client's ModuleClassLoader 472 fba92d3 null ons-sdk's ModuleClassLoader 70 23348b5d null tair-plugin's ModuleClassLoader 1053 7c9d8e2 null tddl-client's ModuleClassLoader 2354 4988d8b8 null config-client's ModuleClassLoader 93 429bffaa null diamond-client's ModuleClassLoader 360 3d5c822d null pandolet's ModuleClassLoader 99 41e1e210 null hsf's ModuleClassLoader 1796 3232a28a null acl.plugin's ModuleClassLoader 379 67080771 null buc.sso.client.plugin's ModuleClassLoader 195 13b6aecc null unitrouter's ModuleClassLoader 64 7e5afaa6 null switch's ModuleClassLoader 104 24313fcc null hsf-notify-client's ModuleClassLoader 57 4d0f2471 null java.net.URLClassLoader@7ec7ffd3 285 7ec7ffd3 sun.misc.Launcher$ExtClassLoader@a38d7a3 javax.management.remote.rmi.NoCallStackClassLoader@53f65459 1 53f65459 null javax.management.remote.rmi.NoCallStackClassLoader@2833cc44 1 2833cc44 null org.jvnet.hk2.internal.DelegatingClassLoader@72cda8ee 1 72cda8ee monitor's ModuleClassLoader org.jvnet.hk2.internal.DelegatingClassLoader@1f57f96d 1 1f57f96d monitor's ModuleClassLoader sun.misc.Launcher$AppClassLoader@14dad5dc 77 14dad5dc sun.misc.Launcher$ExtClassLoader@a38d7a3 sun.misc.Launcher$ExtClassLoader@a38d7a3 46 a38d7a3 null sun.reflect.misc.MethodUtil@1201f221 1 1201f221 sun.misc.Launcher$AppClassLoader@14dad5dc ``` * 查看ClassLoader的继承树 ```shell $ classloader -t +-BootstrapClassLoader +-unitrouter's ModuleClassLoader +-diamond-client's ModuleClassLoader +-sun.misc.Launcher$ExtClassLoader@548a102f | +-sun.misc.Launcher$AppClassLoader@14dad5dc | +-com.taobao.arthas.agent.AgentLauncher$1@334e6bb8 | | +-sun.reflect.DelegatingClassLoader@328b3a05 | | +-sun.reflect.DelegatingClassLoader@73f44f24 ``` * 查看URLClassLoader实际的urls ```shell $ classloader -c 5ffe9775 file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/commons-lang-2.6.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/log4j-1.2.16.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/logger.api-0.1.4.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/pandora.api-2.0.7-SNAPSHOT.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/pandora.container-2.0.7-SNAPSHOT.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/pandora.thirdcontainer-2.0.7-SNAPSHOT.jar file:/Users/hello/soft/taobao-tomcat-7.0.64/deploy/taobao-hsf.sar/lib/picocontainer-2.14.3.jar ``` * 使用ClassLoader去查找resource ```shell $ classloader -c 226b143b -r META-INF/MANIFEST.MF jar:file:/Users/hello/.m2/repository/javax/enterprise/cdi-api/1.0/cdi-api-1.0.jar!/META-INF/MANIFEST.MF jar:file:/Users/hello/.m2/repository/javax/annotation/jsr250-api/1.0/jsr250-api-1.0.jar!/META-INF/MANIFEST.MF ``` 也可以尝试查找类的class文件： ```shell $ classloader -c 1b6d3586 -r java/lang/String.class jar:file:/Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/jre/lib/rt.jar!/java/lang/String.class ```