Fix classloaderhash problem in advance tutorial (#1417)

Signed-off-by: hollowman6 <hollowman186@vip.qq.com>

tutorials/katacoda/arthas-advanced-cn/case-classloader.md

@@ -80,12 +80,13 @@ $ classloader -t
 
         +-org.apache.jasper.servlet.JasperLoader@21ae0fe2
 ```
+注意：请使用你的classLoaderHash值覆盖 `<classLoaderHash>` ，然后手动执行下面相关命令：
 
 ### 列出ClassLoader的urls
 
 比如上面查看到的spring LaunchedURLClassLoader的 hashcode是`1be6f5c3`，可以通过`-c`参数来列出它的所有urls：
 
-`classloader -c 1be6f5c3`{{execute T2}}
+`classloader -c <classLoaderHash>`
 
 ```
 $ classloader -c 1be6f5c3
@@ -97,7 +98,7 @@ jar:file:/home/scrapbook/tutorial/demo-arthas-spring-boot.jar!/BOOT-INF/lib/spri
 
 ### 加载指定ClassLoader里的资源文件
 
-查找指定的资源文件： `classloader -c 1be6f5c3 -r logback-spring.xml`{{execute T2}}
+查找指定的资源文件： `classloader -c <classLoaderHash> -r logback-spring.xml`
 
 ```
 $ classloader -c 1be6f5c3 -r logback-spring.xml
@@ -108,7 +109,7 @@ $ classloader -c 1be6f5c3 -r logback-spring.xml
 
 比如用上面的spring LaunchedURLClassLoader 尝试加载 `java.lang.String` ：
 
-`classloader -c 1be6f5c3 --load java.lang.String`{{execute T2}}
+`classloader -c <classLoaderHash> --load java.lang.String`
 
 ```
 $ classloader -c 1be6f5c3 --load java.lang.String

tutorials/katacoda/arthas-advanced-cn/case-jad-mc-redefine.md

@@ -45,11 +45,15 @@ $ sc -d *UserController | grep classLoaderHash
 
 可以发现是 spring boot `LaunchedURLClassLoader@1be6f5c3` 加载的。
 
+请记下你的classLoaderHash，后面需要使用它。在这里，它是 `1be6f5c3`。
+
+注意：请使用你的classLoaderHash值覆盖 `<classLoaderHash>` ，然后手动执行这些命令：
+
 ### mc
 
 保存好`/tmp/UserController.java`之后，使用`mc`(Memory Compiler)命令来编译，并且通过`-c`参数指定ClassLoader：
 
-`mc -c 1be6f5c3 /tmp/UserController.java -d /tmp`{{execute T2}}
+`mc -c <classLoaderHash> /tmp/UserController.java -d /tmp`
 
 ```bash
 $ mc -c 1be6f5c3 /tmp/UserController.java -d /tmp

tutorials/katacoda/arthas-advanced-cn/case-logger-config-problem.md

@@ -6,11 +6,11 @@
 
 以`UserController`为例，它使用的是slf4j api，但实际使用到的logger系统是logback。
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -28,15 +28,15 @@ $ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
 ### 获取logback实际加载的配置文件
 
 
-`ognl -c 1be6f5c3 '#map1=@org.slf4j.LoggerFactory@getLogger("root").loggerContext.objectMap, #map1.get("CONFIGURATION_WATCH_LIST")'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '#map1=@org.slf4j.LoggerFactory@getLogger("root").loggerContext.objectMap, #map1.get("CONFIGURATION_WATCH_LIST")'`{{execute T2}}
 
 
 ### 使用classloader命令查找可能存在的logger配置文件
 
-`classloader -c 1be6f5c3 -r logback-spring.xml`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback-spring.xml`{{execute T2}}
 
 ```
-$ classloader -c 1be6f5c3 -r logback-spring.xml
+$ classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback-spring.xml
  jar:file:/Users/hengyunabc/code/java/spring-boot-inside/demo-arthas-spring-boot/target/demo-arthas-spring-boot-0.0.1-SNAPSHOT.jar!/BOOT-INF/classes!/logback-spring.xml
 
 Affect(row-cnt:1) cost in 13 ms.
@@ -45,8 +45,8 @@ Affect(row-cnt:1) cost in 13 ms.
 
 可以尝试加载容易冲突的文件：
 
-`classloader -c 1be6f5c3 -r logback.xml`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback.xml`{{execute T2}}
 
-`classloader -c 1be6f5c3 -r log4j.properties`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r log4j.properties`{{execute T2}}
 
 

tutorials/katacoda/arthas-advanced-cn/case-ognl-update-logger-level.md

@@ -14,10 +14,10 @@ $ sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
 
 ### 用ognl获取logger
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -36,14 +36,14 @@ $ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
 
 ### 单独设置UserController的logger level
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
 
 再次获取`UserController@logger`，可以发现已经是`DEBUG`了：
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -62,5 +62,5 @@ $ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
 
 通过获取`root` logger，可以修改全局的logger level：
 
-`ognl -c 1be6f5c3 '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
 

tutorials/katacoda/arthas-advanced-cn/ognl.md

@@ -18,15 +18,36 @@ $ sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
  classLoaderHash   1be6f5c3
 ```
 
+注意hashcode是变化的，需要先查看当前的ClassLoader信息，提取对应ClassLoader的hashcode。
+
+如果你使用`-c`，你需要手动输入hashcode：`-c <hashcode>`
+
+```bash
+$ ognl -c 1be6f5c3 @com.example.demo.arthas.user.UserController@logger
+```
+
+对于只有唯一实例的ClassLoader可以通过`--classLoaderClass`指定class name，使用起来更加方便：
+
+```bash
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader  @org.springframework.boot.SpringApplication@logger
+@Slf4jLocationAwareLog[
+    FQCN=@String[org.apache.commons.logging.LogAdapter$Slf4jLocationAwareLog],
+    name=@String[org.springframework.boot.SpringApplication],
+    logger=@Logger[Logger[org.springframework.boot.SpringApplication]],
+]
+```
+
+ `--classLoaderClass` 的值是ClassLoader的类名，只有匹配到唯一的ClassLoader实例时才能工作，目的是方便输入通用命令，而`-c <hashcode>`是动态变化的。
+
 ### 获取静态类的静态字段
 
 获取`UserController`类里的`logger`字段：
 
-`ognl -c 1be6f5c3 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
 
 还可以通过`-x`参数控制返回值的展开层数。比如：
 
-`ognl -c 1be6f5c3 -x 2 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -x 2 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
 
 ### 执行多行表达式，赋值给临时变量，返回一个List
 

tutorials/katacoda/arthas-advanced-en/case-classloader.md

@@ -81,11 +81,13 @@ $ classloader -t
         +-org.apache.jasper.servlet.JasperLoader@21ae0fe2
 ```
 
+Note: Please replace `<classLoaderHash>` with your classLoaderHash above, then execute the related commands manually in the following steps:
+
 ### List the urls of the ClassLoader
 
 For example, the hashcode of spring `LaunchedURLClassLoader` viewed above is `1be6f5c3`, and all its urls can be listed by the `-c` parameter:
 
-`classloader -c 1be6f5c3`{{execute T2}}
+`classloader -c <classLoaderHash>`
 
 ```
 $ classloader -c 1be6f5c3
@@ -97,7 +99,7 @@ jar:file:/home/scrapbook/tutorial/demo-arthas-spring-boot.jar!/BOOT-INF/lib/spri
 
 ### Load the resource file in the specified ClassLoader
 
-Load the specified resource file: `classloader -c 1be6f5c3 -r logback-spring.xml`{{execute T2}}
+Load the specified resource file: `classloader -c <classLoaderHash> -r logback-spring.xml`
 
 ```
 $ classloader -c 1be6f5c3 -r logback-spring.xml
@@ -108,7 +110,7 @@ $ classloader -c 1be6f5c3 -r logback-spring.xml
 
 For example, try loading `java.lang.String` with spring LaunchedURLClassLoader :
 
-`classloader -c 1be6f5c3 --load java.lang.String`{{execute T2}}
+`classloader -c <classLoaderHash> --load java.lang.String`
 
 ```
 $ classloader -c 1be6f5c3 --load java.lang.String

tutorials/katacoda/arthas-advanced-en/case-jad-mc-redefine.md

@@ -46,11 +46,15 @@ $ sc -d *UserController | grep classLoaderHash
 
 It can be found that it is loaded by spring boot `LaunchedURLClassLoader@1be6f5c3`.
 
+Please write down your classLoaderHash here, in the case here, it's `1be6f5c3`. It will be used in the future steps.
+
+Note: Please replace `<classLoaderHash>` with your classLoaderHash above, then execute the related commands manually in the following steps:
+
 ### mc
 
 After saving `/tmp/UserController.java`, compile with the `mc` (Memory Compiler) command and specify the ClassLoader with the `-c` option:
 
-`mc -c 1be6f5c3 /tmp/UserController.java -d /tmp`{{execute T2}}
+`mc -c <classLoaderHash> /tmp/UserController.java -d /tmp`
 
 ```bash
 $ mc -c 1be6f5c3 /tmp/UserController.java -d /tmp

tutorials/katacoda/arthas-advanced-en/case-logger-config-problem.md

@@ -7,11 +7,11 @@ In this case, show how to troubleshoot logger conflicts.
 
 Take `UserController` as an example, it uses slf4j api, but the actual logger system used is logback.
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -29,15 +29,15 @@ $ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
 ### Find the configuration file actually loaded by the logback
 
 
-`ognl -c 1be6f5c3 '#map1=@org.slf4j.LoggerFactory@getLogger("root").loggerContext.objectMap, #map1.get("CONFIGURATION_WATCH_LIST")'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '#map1=@org.slf4j.LoggerFactory@getLogger("root").loggerContext.objectMap, #map1.get("CONFIGURATION_WATCH_LIST")'`{{execute T2}}
 
 
 ### Use the classloader command to find possible logger configuration files
 
-`classloader -c 1be6f5c3 -r logback-spring.xml`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback-spring.xml`{{execute T2}}
 
 ```
-$ classloader -c 1be6f5c3 -r logback-spring.xml
+$ classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback-spring.xml
  jar:file:/Users/hengyunabc/code/java/spring-boot-inside/demo-arthas-spring-boot/target/demo-arthas-spring-boot-0.0.1-SNAPSHOT.jar!/BOOT-INF/classes!/logback-spring.xml
 
 Affect(row-cnt:1) cost in 13 ms.
@@ -46,8 +46,8 @@ You can know the specific source of the loaded configuration.
 
 You can try to load files that are prone to conflict:
 
-`classloader -c 1be6f5c3 -r logback.xml`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback.xml`{{execute T2}}
 
-`classloader -c 1be6f5c3 -r log4j.properties`{{execute T2}}
+`classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r log4j.properties`{{execute T2}}
 
 

tutorials/katacoda/arthas-advanced-en/case-ognl-update-logger-level.md

@@ -12,10 +12,10 @@ $ sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
 
 ### Use ognl command to get the logger
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -36,14 +36,14 @@ The user can know that `UserController@logger` actually uses logback. Because `l
 
 ### Change the logger level of UserController
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
 
 Get `UserController@logger` again, the user can see that it is already `DEBUG`:
 
-`ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'`{{execute T2}}
 
 ```bash
-$ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
 @Logger[
     serialVersionUID=@Long[5454405123156820674],
     FQCN=@String[ch.qos.logback.classic.Logger],
@@ -62,5 +62,5 @@ $ ognl -c 1be6f5c3 '@com.example.demo.arthas.user.UserController@logger'
 
 By getting the `root` logger, the user can modify the global logger level:
 
-`ognl -c 1be6f5c3 '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'`{{execute T2}}
 

tutorials/katacoda/arthas-advanced-en/ognl.md

@@ -20,15 +20,35 @@ $ sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
  classLoaderHash   1be6f5c3
 ```
 
+Please write down your classLoaderHash here since it's dynamic. In the case here, it's `1be6f5c3`.
+
+if you use`-c`, you have to manually type hashcode by `-c <hashcode>`.
+
+```bash
+$ ognl -c 1be6f5c3 @com.example.demo.arthas.user.UserController@logger
+```
+
+For classloader with only one instance, it can be specified by `--classLoaderClass` using class name, which is more convenient to use.
+
+```bash
+$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader  @org.springframework.boot.SpringApplication@logger
+@Slf4jLocationAwareLog[
+    FQCN=@String[org.apache.commons.logging.LogAdapter$Slf4jLocationAwareLog],
+    name=@String[org.springframework.boot.SpringApplication],
+    logger=@Logger[Logger[org.springframework.boot.SpringApplication]],
+]
+```
+The value of `--classloaderclass` is the class name of classloader. It can only work when it matches a unique classloader instance. The purpose is to facilitate the input of general commands. However, `-c <hashcode>` is dynamic.
+
 ### Get static fields of static classes
 
 Get the `logger` field of the `UserController` class:
 
-`ognl -c 1be6f5c3 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
 
 Control the number of expansion layers of the return value with the `-x` parameter. such as:
 
-`ognl -c 1be6f5c3 -x 2 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
+`ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -x 2 @com.example.demo.arthas.user.UserController@logger`{{execute T2}}
 
 ### Execute multi-line expressions