category: Concept
redirect_from:
- /docs/v0.4.0/concept/extractor/
- /docs/latest/concept/extractor/
title: “变量提取模块”
sort_title: “3”
变量提取模块，是一系列变量提取器的集合，一般格式如下：
"extractor": {
"type": 1,//提取器类型，1指索引式提取，2指模板式提取
"extractions": [
{//一个提取器
"type": "Query",
"name": "wd"
},
{
"type": "Header",
"name": "from",
"default": "this_is_default_value"
}
]
}关于两种变量提取器的描述，可以参看#issues15