LangChain4j开篇

系列未完待续

1.概述

LangChain4j（https://docs.langchain4j.dev/），由Python AI框架LangChain而来，是一款Java调用AI大模型的工具，类似的还有Spring AI，用于开发基于Java语言的大模型应用。

2.快速开始

截至目前，官网上langchain4j的最高版本是1.8.0-beta15，通过该版本整合SpringBoot 3.x，需要jdk17+

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

    <groupId>org.example</groupId>
    <artifactId>langchain4j-test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.5.4</version>
    </parent>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>

        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai-spring-boot-starter</artifactId>
            <version>1.8.0-beta15</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>


</project>

application.yml

langchain4j:
  open-ai:
    chat-model:
      base-url: https://api.gptsapi.net/v1
      api-key: ${OPEN_AI_KEY}
      model-name: gpt-5-chat
      log-requests: true
      log-responses: true

package org.example.test;

import dev.langchain4j.data.message.ChatMessage;
import dev.langchain4j.data.message.SystemMessage;
import dev.langchain4j.data.message.UserMessage;
import dev.langchain4j.model.chat.ChatModel;
import dev.langchain4j.model.chat.response.ChatResponse;
import jakarta.annotation.Resource;
import org.example.Main;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.Arrays;
import java.util.List;

@SpringBootTest(classes = Main.class)
public class ChatTest {

    @Resource
    private ChatModel chatModel;

    @Test
    public void test() {
        List<ChatMessage> messages = Arrays.asList(
                new SystemMessage("你是一个数学老师，用简单易懂的方式解释数学概念。"),
                new UserMessage("什么是微积分？")
        );
        ChatResponse chatResponse = chatModel.chat(messages);
        System.out.println(chatResponse);
    }

}