# options
[`options`在线教程 ](https://arthas.aliyun.com/doc/arthas-tutorials.html?language=cn&id=command-options )
::: tip
全局开关
:::
| 名称 | 默认值 | 描述 |
| ---------------------- | ------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------- |
| unsafe | false | 是否支持对系统级别的类进行增强，打开该开关可能导致把 JVM 搞挂，请慎重选择！ |
| dump | false | 是否支持被增强了的类 dump 到外部文件中， ，
| batch-re-transform | true | 是否支持批量对匹配到的类执行 retransform 操作 |
| json-format | false | 是否支持 json 化的输出 |
| disable-sub-class | false | 是否禁用子类匹配，默认在匹配目标类的时候会默认匹配到其子类，如果想精确匹配，可以关闭此开关 |
| support-default-method | true | 是否支持匹配到 default method， ， #1105 ](https://github.com/alibaba/arthas/issues/1105 ) |
| save-result | false | 是否打开执行结果存日志功能，打开之后所有命令的运行结果都将保存到`~/logs/arthas-cache/result.log`中 |
| job-timeout | 1d | 异步后台任务的默认超时时间，超过这个时间，任务自动停止；比如设置 1d, 2h, 3m, 25s，
| print-parent-fields | true | 是否打印在 parent class 里的 filed |
| verbose | false | 是否打印更多详细信息 |
| strict | true | 是否启用 strict 模式 |
## 查看所有的 options
```bash
$ options
LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION
-------------------------------------------------------------------------------------------------------
0 boolea unsafe false Option to support sy This option enables to proxy functionality
n stem-level class of JVM classes. Due to serious security r
isk a JVM crash is possibly be introduced.
Do not activate it unless you are able to
manage.
1 boolea dump false Option to dump the e This option enables the enhanced classes t
n nhanced classes o be dumped to external file for further d
e-compilation and analysis.
1 boolea batch-re-tra true Option to support ba This options enables to reTransform classe
n nsform tch reTransform Clas s with batch mode.
s
2 boolea json-format false Option to support JS This option enables to format object outpu
n ON format of object t with JSON when -x option selected.
output
1 boolea disable-sub- false Option to control in This option disable to include sub class w
n class clude sub class when hen matching class.
class matching
1 boolea support-defa true Option to control in This option disable to include default met
n ult-method clude default method hod in interface when matching class.
in interface when c
lass matching
1 boolea save-result false Option to print comm This option enables to save each command's
n and's result to log result to log file, which path is ${user.
file home}/logs/arthas-cache/result.log.
2 String job-timeout 1d Option to job timeou This option setting job timeout,The unit c
t an be d, h, m, s for day, hour, minute, se
cond. 1d is one day in default
1 boolea print-parent true Option to print all This option enables print files in parent
n -fields fileds in parent cla class, default value true.
ss
1 boolea verbose false Option to print verb This option enables print verbose informat
n ose information ion, default value false.
1 boolea strict true Option to strict mod By default, strict mode is true, not allow
n e ed to set object properties. Want to set o
bject properties, execute `options strict
false`
```
## 获取 option 的值
```
$ options json-format
LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION
--------------------------------------------------------------------------------------------
2 bool json-format false Option to support This option enables to format object
ean JSON format of obj output with JSON when -x option selec
ect output ted.
```
::: tip
默认情况下`json-format`为 false，
:::
## 设置指定的 option
例如，想打开执行结果存日志功能，输入如下命令即可：
```
$ options save-result true
NAME BEFORE-VALUE AFTER-VALUE
----------------------------------------
save-result false true
```
## 打开 unsafe 开关，支持 jdk package 下的类
默认情况下，`watch`/`trace`/`tt`/`trace`/`monitor`等命令不支持`java.*` package 下的类。可以设置`unsafe`为 true，
```bash
$ options unsafe true
NAME BEFORE-VALUE AFTER-VALUE
-----------------------------------
unsafe false true
```
```bash
$ watch java.lang.invoke.Invokers callSiteForm
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 61 ms, listenerId: 1
```
## 关闭 strict 模式，允许在 ognl 表达式里设置对象属性
::: tip
since 3.6.0
:::
对于新用户，在编写 ognl 表达式时，可能会出现误用。
比如对于`Student`，判断年龄等于 18 时，可能条件表达式会误写为`target.age=18`，这个表达式实际上是把当前对象的`age`设置为 18 了。正确的写法是`target.age==18`。
为了防止出现类似上面的误用，
以`MathGame`为例，会出现以下的错误提示。
```
$ watch demo.MathGame primeFactors 'target' 'target.illegalArgumentCount=1'
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 206 ms, listenerId: 1
watch failed, condition is: target.illegalArgumentCount=1, express is: target, By default, strict mode is true, not allowed to set object properties. Want to set object properties, execute `options strict false` , visit /Users/admin/logs/arthas/arthas.log for more details.
```
用户如果确定要在`ognl`表达式里更新对象，可以执行`options strict false`，关闭`strict`模式。
- 更多信息参考： https://github.com/alibaba/arthas/issues/2128
