add case-ognl-practise-cn

tutorials/katacoda/case-ognl-practise-cn/README.md

@@ -0,0 +1,25 @@
+# Katacoda Hello World
+This is an example repository. Starting building your own scenario by editing the files in this directory. Create additional scenarios by adding additional directories to the top level folder.
+
+
+## index.json
+The file _index.json_ contains all the information about the scenario. It has the title, description and a heading for each step.
+
+The file also contains an imageid. This refers to the Katacoda environment. Here are some environment image IDs you may find useful:
+
+| **Environment**  | **Image ID**  |
+|------------------|---------------|
+| Docker           | docker        |
+| Kubernetes       | kubernetes    |
+| CoreOS           | coreos        |
+| Node.js v6       | node6         |
+| Go               | go            |
+| C#               | c#            |
+| Java             | java8         |
+| Bash             | bash          |
+
+## Pro Author Accounts
+Interested in metrics, private repositories and environments for classroom teaching? Update to become a Pro Author at https://katacoda.com/teach
+
+## Interactive Developer Portals
+Want to take your scenarios to the next level? Visit https://katacoda.com/embed

tutorials/katacoda/case-ognl-practise-cn/finish.md

@@ -0,0 +1,20 @@
+我们演示如何调试Arthas的`ognl`表达式。如果有更多的技巧或者使用疑问，欢迎在Issue里提出。
+
+
+更多参考：
+
+* 特殊用法请参考：[https://github.com/alibaba/arthas/issues/71](https://github.com/alibaba/arthas/issues/71)
+* OGNL表达式官网：[https://commons.apache.org/proper/commons-ognl/language-guide.html](https://commons.apache.org/proper/commons-ognl/language-guide.html)
+
+
+---
+
+* Issues: https://github.com/alibaba/arthas/issues
+* 文档： https://arthas.aliyun.com/doc
+
+如果您在使用Arthas，请让我们知道。您的使用对我们非常重要：[查看](https://github.com/alibaba/arthas/issues/111)
+
+欢迎关注公众号，获取Arthas项目的信息、源码分析、案例实践。
+
+![Arthas公众号](/arthas/scenarios/common-resources/assets/qrcode_gongzhonghao.jpg)
+

tutorials/katacoda/case-ognl-practise-cn/index.json

@@ -0,0 +1,32 @@
+{
+  "noindex": true,
+  "title": "调试 Arthas 的 ognl 表达式",
+  "description": "调试 Arthas 的 ognl 表达式",
+  "details": {
+      "steps": [
+          {
+              "text": "step1.md",
+              "code": "setup.sh"
+          }
+      ],
+      "intro": {
+          "text": "intro.md",
+          "credits": ""
+      },
+      "finish": {
+        "text": "finish.md"
+      }
+  },
+  "files": [
+  ],
+  "environment": {
+      "hidefinish": true,
+      "hideHiddenFiles": true,
+      "uilayout": "editor-terminal",
+      "uisettings": "javascript",
+      "uieditorpath": "/root/example/ognl-demo"
+  },
+  "backend": {
+      "imageid": "openjdk:15"
+  }
+}

tutorials/katacoda/case-ognl-practise-cn/intro.md

@@ -0,0 +1,9 @@
+![Arthas](https://arthas.aliyun.com/doc/_images/arthas.png)
+
+`Arthas` 是Alibaba开源的Java诊断工具，深受开发者喜爱。在线排查问题，无需重启；动态跟踪Java代码；实时监控JVM状态。
+
+
+本教程会以一个简单的应用为例，演示如果调试`ognl`表达式。
+
+* Github: https://github.com/alibaba/arthas
+* 文档: https://arthas.aliyun.com/doc/

tutorials/katacoda/case-ognl-practise-cn/setup.sh

@@ -0,0 +1 @@
+mkdir -p example; cd example/; git clone https://github.com/hengyunabc/ognl-demo.git ; cd ognl-demo

tutorials/katacoda/case-ognl-practise-cn/step1.md

@@ -0,0 +1,41 @@
+
+演示Arthas里`watch`命令中`ognl`表达式的工作流程。用户可以自己修改`Demo.java`里的表达式，再执行验证。
+
+项目地址： https://github.com/hengyunabc/ognl-demo
+# 打开Demo.java文件
+
+`src/main/java/com/example/ognl/Demo.java`{{open}}
+
+# 编译运行代码
+
+`mvn compile exec:java`{{execute}}
+
+代码里的表达式：
+
+```java
+String watchExpress = "{target, params, returnObj, #cost}";
+String conditionExpress = "params[0] > 1 && #cost > 0.1";
+```
+
+结果类似下面的表达式：
+
+```bash
+watch com.example.ognl.TestService test "{target, params, returnObj, #cost}" "params[0] > 1 && #cost > 0.1" -x 3
+```
+
+# 查看函数抛出异常时的表达式结果
+
+`mvn compile exec:java -DexceptionCase=true`{{execute}}
+
+代码里的表达式：
+
+```java
+String watchExpress = "{target, params, throwExp}";
+String conditionExpress = "params[0] > 1";
+```
+
+结果类似下面的表达式：
+
+```bash
+watch com.example.ognl.TestService test "{target, params, throwExp}" "params[0] > 1" -e -x 2
+```