Qdrant

# Qdrant for Java: Complete Examples

This file provides comprehensive code examples for integrating Qdrant with Java and Spring Boot applications.

## 1. Complete Spring Boot Application with Qdrant

This example demonstrates a full Spring Boot application with Qdrant integration for vector search.

### Project Structure
```
/src/main/java/com/example/qdrantdemo/
├── QdrantDemoApplication.java
├── config/
│   ├── QdrantConfig.java
│   └── Langchain4jConfig.java
├── controller/
│   ├── SearchController.java
│   └── RagController.java
├── service/
│   ├── VectorSearchService.java
│   └── RagService.java
└── Application.properties
```

### Dependencies (pom.xml)
```xml
<dependencies>
    <!-- Spring Boot -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- Qdrant Java Client -->
    <dependency>
        <groupId>io.qdrant</groupId>
        <artifactId>client</artifactId>
        <version>1.15.0</version>
    </dependency>

    <!-- LangChain4j -->
    <dependency>
        <groupId>dev.langchain4j</groupId>
        <artifactId>langchain4j</artifactId>
        <version>1.7.0</version>
    </dependency>
    <dependency>
        <groupId>dev.langchain4j</groupId>
        <artifactId>langchain4j-qdrant</artifactId>
        <version>1.7.0</version>
    </dependency>
    <dependency>
        <groupId>dev.langchain4j</groupId>
        <artifactId>langchain4j-all-minilm-l6-v2</artifactId>
        <version>1.7.0</version>
    </dependency>
    <dependency>
        <groupId>dev.langchain4j</groupId>
        <artifactId>langchain4j-open-ai</artifactId>
        <version>1.7.0</version>
    </dependency>
</dependencies>
```

### Application Configuration (application.properties)
```properties
# Qdrant Configuration
qdrant.host=localhost
qdrant.port=6334
qdrant.api-key=

# OpenAI Configuration (for RAG)
openai.api-key=YOUR_OPENAI_API_KEY
```

### Qdrant Configuration
```java
package com.example.qdrantdemo.config;

import io.qdrant.client.QdrantClient;
import io.qdrant.client.QdrantGrpcClient;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class QdrantConfig {

    @Value("${qdrant.host:localhost}")
    private String host;

    @Value("${qdrant.port:6334}")
    private int port;

    @Value("${qdrant.api-key:}")
    private String apiKey;

    @Bean
    public QdrantClient qdrantClient() {
        QdrantGrpcClient grpcClient = QdrantGrpcClient.newBuilder(host, port, false)
            .withApiKey(apiKey)
            .build();

        return new QdrantClient(grpcClient);
    }
}
```

### Vector Search Service
```java
package com.example.qdrantdemo.service;

import io.qdrant.client.QdrantClient;
import io.qdrant.client.grpc.Collections.Distance;
import io.qdrant.client.grpc.Collections.VectorParams;
import io.qdrant.client.grpc.Points.PointStruct;
import io.qdrant.client.grpc.Points.QueryPoints;
import io.qdrant.client.grpc.Points.ScoredPoint;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import jakarta.annotation.PostConstruct;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutionException;

import static io.qdrant.client.PointIdFactory.id;
import static io.qdrant.client.ValueFactory.value;
import static io.qdrant.client.VectorsFactory.vectors;
import static io.qdrant.client.QueryFactory.nearest;

@Service
public class VectorSearchService {

    private final QdrantClient client;

    @Autowired
    private EmbeddingService embeddingService; // Helper service for embeddings

    public static final String COLLECTION_NAME = "document-search";
    public static final int VECTOR_SIZE = 384; // For AllMiniLM-L6-v2

    public VectorSearchService(QdrantClient client) {
        this.client = client;
    }