MongoDB Java Examples - TechMart

A comprehensive collection of Java examples demonstrating MongoDB's capabilities through TechMart, a fictional global e-commerce platform.

🏗️ Project Structure

This is a multi-module Maven project with two implementation approaches:

mongodb-java-examples/
├── pom.xml                          # Parent POM
├── README.md                        # This file
├── docs/
│
├── mongodb-driver-examples/         # Native Java Driver examples
│   ├── pom.xml
│   ├── README.md
│   └── src/main/java/...
│
└── spring-boot-examples/            # Spring Boot + Spring Data examples
    ├── pom.xml
    ├── README.md
    └── src/main/java/...

🎯 Choose Your Approach

Module	Best For	Key Features
mongodb-driver-examples	Direct control, understanding fundamentals	Native driver API, Document class, explicit queries
spring-boot-examples	Rapid development, Spring ecosystem	@Document POJOs, Repository pattern, @Transactional

📖 The TechMart Story

Both modules follow the same compelling narrative - building TechMart from startup to global scale:

1. Launch - Flexible product catalog with the document model
2. Scale - Millions of orders with transactions
3. React - Real-time inventory alerts with change streams
4. Analyze - Business intelligence with aggregations
5. Secure - Customer PII protection with encryption
6. Search - AI-powered semantic search
7. Expand - Global scaling with sharding

🚀 Quick Start

Prerequisites

• Java 17+
• Maven 3.6+
• MongoDB 7.0+ (local) or MongoDB Atlas

Build All Modules

# Clone and build
git clone https://github.com/your-org/mongodb-java-examples.git
cd mongodb-java-examples
mvn clean compile

Run Native Driver Examples

cd mongodb-driver-examples

# Load sample data
mvn exec:java -Dexec.mainClass="com.mongodb.examples.common.SampleDataLoader"

# Run any example
mvn exec:java -Dexec.mainClass="com.mongodb.examples.core.E01_DocumentModel"
mvn exec:java -Dexec.mainClass="com.mongodb.examples.core.E05_AggregationFramework"

Run Spring Boot Examples

cd spring-boot-examples

# Show available examples menu
mvn spring-boot:run

# Run a specific example
mvn spring-boot:run -Dspring-boot.run.arguments="--example=E01"

# Run ALL examples
mvn spring-boot:run -Dspring-boot.run.arguments="--example=ALL"

# Or from parent directory
mvn spring-boot:run -pl spring-boot-examples -Dspring-boot.run.arguments="--example=E05"

🔧 Configuration

Set your MongoDB connection string:

# For local MongoDB
export MONGODB_URI="mongodb://localhost:27017"

# For MongoDB Atlas
export MONGODB_URI="mongodb+srv://user:pass@cluster.mongodb.net/"

# Database name (default: techmart)
export MONGODB_DATABASE="techmart"

📋 Examples Overview

Native Driver Module (17 examples)

Category	Examples
Core MongoDB	E01-E09: Document Model, Schema, CRUD, Indexes, Aggregation, Transactions, Change Streams, Materialized Views, Validation
Time Series	E10-E11: Time Series Collections, Window Functions
Security	E12-E13: Queryable Encryption, Client-Side FLE
Atlas Features	E14-E15: Atlas Search, Vector Search
Scaling	E16-E17: Replica Sets, Sharding

Spring Boot Module (17 examples)

Example	Spring Data Features
E01 Document Model	@Document, @Id, @Indexed, POJO mapping
E02 Flexible Schema	Map<String, Object> for dynamic attributes in POJOs
E03 CRUD Operations	Repository methods, derived queries
E04 Index Types	@Indexed, @CompoundIndex, @TextIndexed, indexOps()
E05 Aggregation	@Aggregation, MongoTemplate, fluent API
E06 Transactions	@Transactional, MongoTransactionManager
E07 Change Streams	MongoTemplate.watch(), ChangeStreamIterable
E08 Materialized Views	$merge aggregation, pre-computed analytics
E09 Schema Validation	Bean Validation (JSR-380), @Valid, @NotBlank, @Email
E12 Queryable Encryption	Conceptual demo with encrypted POJOs
E13 Client-Side FLE	Per-customer keys, crypto-shredding for GDPR
E10 Time Series	IoT sensor data, time bucketing, TTL
E14 Atlas Search	Full-text, fuzzy matching, autocomplete
E15 Vector Search	AI/semantic search, RAG pattern, embeddings
E16 Replica Set	Read preferences, write concerns, HA

🔄 Side-by-Side Comparison

Feature	Native Driver	Spring Data MongoDB
Document creation	new Document().append(k, v)	POJOs with @Document
CRUD operations	collection.insertOne(doc)	repository.save(entity)
Queries	Filters.eq("field", value)	findByField(value)
Aggregation	collection.aggregate(pipeline)	@Aggregation or MongoTemplate
Transactions	ClientSession explicit	@Transactional automatic
Indexes	collection.createIndex()	@Indexed annotations
Change Streams	collection.watch()	MongoTemplate.watch()
Validation	MongoDB JSON Schema	Bean Validation (JSR-380)

📚 Additional Resources

• MongoDB Java Driver Documentation
• Spring Data MongoDB Reference
• MongoDB University
• MongoDB Atlas

📄 License

Apache License 2.0

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