1 依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.5.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.xu</groupId>
    <artifactId>lang-chain</artifactId>
    <version>1.0.0</version>
    <name>lang-chain</name>

    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>25</java.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>dev.langchain4j</groupId>
                <artifactId>langchain4j-bom</artifactId>
                <version>1.6.0</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>

        <!--Spring Boot 的 Web starter-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--LangChain4j 的 Spring Boot starter-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-spring-boot-starter</artifactId>
        </dependency>

        <!--LangChain4j 针对 OpenAI 的 Spring Boot starter-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai-spring-boot-starter</artifactId>
        </dependency>

        <!--LangChain4j 对 Ollama 的支持库-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-ollama</artifactId>
        </dependency>

        <!--LangChain4j RAG 的最简单方法-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-easy-rag</artifactId>
        </dependency>

        <!--LangChain4j 对 PostgreSQL 向量扩展（pgvector）的支持库-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-pgvector</artifactId>
        </dependency>

        <!--Spring Boot 的开发工具，提供热部署、自动重启等功能，加速开发过程-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!--简化 Java 代码的工具库-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!--Spring Boot 的测试 starter-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

2 配置

server:
  port: 8080

spring:
  application:
    name: lang-chain

logging:
  file:
    name: logs/spring-oracle.log
  level:
    root: INFO
    com.xu: INFO

langchain4j:
  ollama:
    chat-model:
      base-url: http://127.0.0.1:11434
      model-name: gemma3:latest

3 代码

3.1 RagConf

package com.xu.conf;

import dev.langchain4j.data.segment.TextSegment;
import dev.langchain4j.store.embedding.EmbeddingStore;
import dev.langchain4j.store.embedding.pgvector.PgVectorEmbeddingStore;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class RagConf {

	@Bean
	public EmbeddingStore<TextSegment> embeddingStore() {
		return PgVectorEmbeddingStore.builder()
				.dropTableFirst(true)
				.createTable(true)
				.table("embedding")
				.user("postgres")
				.host("localhost")
				.password("123456")
				.database("postgres")
				.port(5432)
				.dimension(384)
				.build();
	}

}

3.2 RagController

package com.xu.chat.controller;

import dev.langchain4j.data.document.Document;
import dev.langchain4j.data.document.loader.FileSystemDocumentLoader;
import dev.langchain4j.data.segment.TextSegment;
import dev.langchain4j.store.embedding.EmbeddingStore;
import dev.langchain4j.store.embedding.EmbeddingStoreIngestor;
import lombok.AllArgsConstructor;
import org.apache.commons.collections4.CollectionUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@AllArgsConstructor
@RequestMapping("/ollama/rag")
public class RagController {

	private final EmbeddingStore<TextSegment> embeddingStore;

	@GetMapping("/test")
	public Object chat() {
		List<Document> documents = FileSystemDocumentLoader.loadDocuments("E:\\Test");
		if (CollectionUtils.isEmpty(documents)) {
			return 0;
		}
		EmbeddingStoreIngestor.ingest(documents, embeddingStore);
		return documents.size();
	}

}

4 结果