如何使用jq工具提取JSON中指定前缀的text字段值

需要从以下示例JSON中提取text字段满足以下条件的值：

• 以23.acmestable.0.开头
• 非SNAPSHOT格式

尝试执行以下jq命令时出错：

jq -r'.[].content.data[]["content-item"]'|jq -r '.[]| select (.text |startswith("^23.acmestable.0."))'

预期结果：

23.acmestable.0.22
23.acmestable.0.23
23.acmestable.0.24
23.acmestable.0.25

使用硬编码值执行以下命令可返回结果：

'.[].content.data[]["content-item"]'|jq -r '.[]| select (.text=="23.acme.0.23")'

返回结果：

{
  "text": "23.acmestable.0.23"
}

示例JSON：

[
   {
      "content": {
         "data": [
             {
               "content-item": [
                  {
                     "resourceURI": "https://acme.example.com/service/local/repositories/public/content/com/acme/acme-files/23.acmestable.0.0-SNAPSHOT/"
                  },
                  {
                     "relativePath": "/com/acme/acme-files/23.acmestable.0.0-SNAPSHOT/"
                  },
                  {
                     "text": "23.acmestable.0.0-SNAPSHOT"
                  },
                  {
                     "leaf": "false"
                  },
                  {
                     "lastModified": "2022-10-06 11:54:58.0 UTC"
                  },
                  {
                     "sizeOnDisk": "-1"
                  }
               ]
            },
             {
               "content-item": [
                  {
                     "resourceURI": "https://acme.example.com/service/local/repositories/public/content/com/acme/acme-files/23.acmestable.0.24/"
                  },
                  {
                     "relativePath": "/com/acme/acme-files/23.acmestable.0.24/"
                  },
                  {
                     "text": "23.acmestable.0.24"
                  },
                  {
                     "leaf": "false"
                  },
                  {
                     "lastModified": "2022-10-07 03:17:23.0 UTC"
                  },
                  {
                     "sizeOnDisk": "-1"
                  }
               ]
            },
             {
               "content-item": [
                  {
                     "resourceURI": "https://acme.example.com/service/local/repositories/public/content/com/acme/acme-files/23.acmestable.0.25/"
                  },
                  {
                     "relativePath": "/com/acme/acme-files/23.acmestable.0.25/"
                  },
                  {
                     "text": "23.acmestable.0.25"
                  },
                  {
                     "leaf": "false"
                  },
                  {
                     "lastModified": "2022-10-07 03:17:23.0 UTC"
                  },
                  {
                     "sizeOnDisk": "-1"
                  }
               ]
            },
            {
               "content-item": [
                  {
                     "resourceURI": "https://acme.example.com/service/local/repositories/public/content/com/acme/acme-files/23.acmestable.0.22/"
                  },
                  {
                     "relativePath": "/com/acme/acme-files/23.acmestable.0.22/"
                  },
                  {
                     "text": "23.acmestable.0.22"
                  },
                  {
                     "leaf": "false"
                  },
                  {
                     "lastModified": "2022-10-07 03:17:23.0 UTC"
                  },
                  {
                     "sizeOnDisk": "-1"
                  }
               ]
            },
             {
               "content-item": [
                  {
                     "resourceURI": "https://acme.example.com/service/local/repositories/public/content/com/acme/acme-files/23.acmestable.0.23/"
                  },
                  {
                     "relativePath": "/com/acme/acme-files/23.acmestable.0.23/"
                  },
                  {
                     "text": "23.acmestable.0.23"
                  },
                  {
                     "leaf": "false"
                  },
                  {
                     "lastModified": "2022-10-07 03:17:23.0 UTC"
                  },
                  {
                     "sizeOnDisk": "-1"
                  }
               ]
            }
         ]
      }
   }
]

错误分析 #

1. startswith()函数不需要加正则锚点^，它本身就是匹配字符串开头，加^会导致匹配字面量包含^的字符串，自然无结果；
2. 原命令未过滤带-SNAPSHOT的项；
3. 分两次调用jq效率低，可合并为一次处理。

正确的jq命令 #

jq -r '.[].content.data[]."content-item"[] | select(.text) | .text | select(startswith("23.acmestable.0.") and (test("-SNAPSHOT$") | not))'

命令解释 #

• .[].content.data[]."content-item"[]：逐层遍历JSON结构，定位所有content-item数组内的元素；
• select(.text)：筛选出包含text键的元素，排除resourceURI等无关项；
• .text：提取text字段的具体值；
• select(startswith("23.acmestable.0.") and (test("-SNAPSHOT$") | not))：最终筛选出符合前缀要求且非SNAPSHOT的值。

执行该命令后，将得到预期结果：

23.acmestable.0.24
23.acmestable.0.25
23.acmestable.0.22
23.acmestable.0.23

内容的提问来源于stack exchange，提问作者Hare Krshn