Ways to write MongoDB Aggregation Pipeline using Java and Spring Boot

Pic Credit: https://www.tech-prastish.com

Aggregation Operations

Aggregation operations process multiple documents and return computed results. We can use aggregation operations to:

• Group values from multiple documents together.
• Perform operations on the grouped data to return a single result.
• Analyze data changes over time.

One way to perform aggregation operations is to write Aggregation Pipeline

In this article, we will deep dive into writing Aggregation Pipeline in Java with or without Spring Boot.

Aggregation Pipeline

The Aggregation Pipeline processes the input documents in several stages in a serial order. Each result produced in one stage is passed on to the next stage where further processing can be done on this subset of documents to achieve the final aggregated result.

Sample Pipeline

Using Native MongoDB Java Driver

1. Easiest way is to write every stage in the form of Document.

Pipeline:

2. Using the inbuilt aggregate method present in MongoDB Java driver

Using Spring Boot

1. Using @Aggregation annotation in MongoRepository

2. Using aggregate method present in Spring Data MongoDB Template

Reference: https://www.mongodb.com