求助：如何使用Jolt插入当前日期/时间

Hey there! Let's work through your Jolt date/time insertion issue—since ${now()} doesn't work natively with Jolt, I'll break down practical solutions for you.

First, the key context: #

Jolt is built exclusively for JSON-to-JSON transformations—it doesn't have built-in support for dynamic variables like ${now()} to generate dates on the fly. That's why your initial attempt didn't produce any date/time in the output.

Here are two actionable solutions: #

1. Inject the timestamp before running Jolt (Application/Java Layer)

If you're using Jolt in a Java application, generate the current date/time first in your code, add it as a field to your input JSON, then use Jolt to map it to your desired output field.

• Example Input JSON (with pre-generated timestamp):

  {
    "userData": {
      "id": 123,
      "name": "Jane Doe"
    },
    "currentTimestamp": "2024-05-20T15:45:00Z"
  }
  

• Jolt Spec to map the timestamp:

  [
    {
      "operation": "shift",
      "spec": {
        "userData": "userData",
        "currentTimestamp": "processedAt" // Maps the pre-generated time to your output field
      }
    }
  ]
  

• Expected Output:

  {
    "userData": {
      "id": 123,
      "name": "Jane Doe"
    },
    "processedAt": "2024-05-20T15:45:00Z"
  }
  

  Pro tip: Use Java's DateTimeFormatter to generate the timestamp in your preferred format (like ISO 8601, shown above).

2. Use your integration tool's built-in date generation (e.g., NiFi, Camel)

If you're using Jolt with a data integration tool like Apache NiFi or Apache Camel, these tools have native ways to generate timestamps before passing data to Jolt:

• For NiFi: Use the UpdateAttribute processor to create a currentTime attribute with the value ${now()} (NiFi supports this variable!), then use JoltTransformJSON to inject this attribute into your input JSON before transformation.
• For Camel: Use the simple language to generate the timestamp (${date:now:yyyy-MM-dd'T'HH:mm:ss'Z'}) and add it to the exchange body before running the Jolt transform.

Quick recap: #

Jolt can't generate dynamic dates on its own, but you can easily work around this by adding the timestamp to your input JSON before running the Jolt transformation—either via your application code or the integration tool you're using with Jolt.

内容的提问来源于stack exchange，提问作者Jason Gregory