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