LangChain4J实战，高效速通

文章目录

• 1.LangChain4J理论概述
• • 介绍
  • 大模型能干什么
  • LLM应用技术架构
  • 大模型开发分类
• 2.LangChain4J之HelloWorld
• • LangChain4J支持的大语言模型
  • 接入阿里云百炼
  • • 获得Api-key
    • 创建工程
    • 创建Module
  • 如果保证多种大模型在系统里共存
  • • DeepSeek
    • 创建Module
• 3.LangChain4J整合Springboot
• • • SpringBoot整合低阶API
    • SpringBoot整合高阶API
    • LangChain4J原生整合
    • LangChain4J-Boot整合
    • 总结
    • 开发

1.LangChain4J理论概述

随着人工智能（AI）技术的迅猛发展，越来越多的开发者开始将目光投向AI应用的开发。然而，目前市场上大多数AI框架和工具如LangChain、PyTorch等主要支持Python，而Java开发者常常面临工具缺乏和学习门槛较高的问题，但是不用担心，谁让Java/Spring群体强大那？，O(∩_∩)O

任何一个框架/XXX云服务器，想要大面积推广，应该不会忘记庞大的Spring社区和Java程序员

https://docs.langchain4j.dev

介绍

大模型能干什么

LLM应用技术架构

https://docs.langchain4j.dev/get-started

大模型开发分类

2.LangChain4J之HelloWorld

LangChain4J支持的大语言模型

https://docs.langchain4j.dev/category/language-models

接入阿里云百炼

https://bailian.console.aliyun.com/

获得Api-key

创建工程

<?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>com.atguigu.stduy</groupId>
    <artifactId>langchain4j-atguiguV5</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>
    <name>langchain4j-atguiguV5-Maven父工程POM配置</name>


    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>17</java.version>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <!-- Spring Boot -->
        <spring-boot.version>3.5.0</spring-boot.version>
        <!-- Spring AI -->
        <spring-ai.version>1.0.0</spring-ai.version>
        <!-- Spring AI Alibaba -->
        <spring-ai-alibaba.version>1.0.0-M6.1</spring-ai-alibaba.version>
        <!-- langchain4j -->
        <langchain4j.version>1.0.1</langchain4j.version>
        <!--langchain4j-community 引入阿里云百炼平台依赖管理清单-->
        <langchain4j-community.version>1.0.1-beta6</langchain4j-community.version>
        <!-- maven plugin -->
        <maven-deploy-plugin.version>3.1.1</maven-deploy-plugin.version>
        <flatten-maven-plugin.version>1.3.0</flatten-maven-plugin.version>
        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!-- Spring Boot -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- Spring AI -->
            <dependency>
                <groupId>org.springframework.ai</groupId>
                <artifactId>spring-ai-bom</artifactId>
                <version>${spring-ai.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- Spring AI Alibaba -->
            <dependency>
                <groupId>com.alibaba.cloud.ai</groupId>
                <artifactId>spring-ai-alibaba-starter</artifactId>
                <version>${spring-ai-alibaba.version}</version>
            </dependency>
            <!--langchain4j的依赖清单，加载BOM后所有langchain4j版本号可以被统一管理起来
            https://docs.langchain4j.dev/get-started
            -->
            <dependency>
                <groupId>dev.langchain4j</groupId>
                <artifactId>langchain4j-bom</artifactId>
                <version>${langchain4j.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--引入阿里云百炼平台依赖管理清单
           https://docs.langchain4j.dev/integrations/language-models/dashscope
           -->
            <dependency>
                <groupId>dev.langchain4j</groupId>
                <artifactId>langchain4j-community-bom</artifactId>
                <version>${langchain4j-community.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-deploy-plugin</artifactId>
                <version>${maven-deploy-plugin.version}</version>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${maven-compiler-plugin.version}</version>
                <configuration>
                    <release>${java.version}</release>
                    <compilerArgs>
                        <compilerArg>-parameters</compilerArg>
                    </compilerArgs>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>flatten-maven-plugin</artifactId>
                <version>${flatten-maven-plugin.version}</version>
                <inherited>true</inherited>
                <executions>
                    <execution>
                        <id>flatten</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>flatten</goal>
                        </goals>
                        <configuration>
                            <updatePomFile>true</updatePomFile>
                            <flattenMode>ossrh</flattenMode>
                            <pomElements>
                                <distributionManagement>remove</distributionManagement>
                                <dependencyManagement>remove</dependencyManagement>
                                <repositories>remove</repositories>
                                <scm>keep</scm>
                                <url>keep</url>
                                <organization>resolve</organization>
                            </pomElements>
                        </configuration>
                    </execution>
                    <execution>
                        <id>flatten.clean</id>
                        <phase>clean</phase>
                        <goals>
                            <goal>clean</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <releases>
                <enabled>false</enabled>
            </releases>
        </repository>
        <repository>
            <id>aliyunmaven</id>
            <name>aliyun</name>
            <url>https://maven.aliyun.com/repository/public</url>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>public</id>
            <name>aliyun nexus</name>
            <url>https://maven.aliyun.com/repository/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

创建Module

引入pom

<?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>

    <parent>
        <groupId>com.atguigu.stduy</groupId>
        <artifactId>langchain4j-atguiguV5</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>langchain4j-01helloworld</artifactId>
    <name>langchain4j-01helloworld入门案例</name>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--langchain4j-open-ai 基础-->
        <!--所有调用均基于 OpenAI 协议标准，实现一致的接口设计与规范LangChain4j 提供与许多 LLM 提供商的集成
        从最简单的开始方式是从 OpenAI 集成开始https://docs.langchain4j.dev/get-started    -->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai</artifactId>
        </dependency>
        <!--langchain4j 高阶-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

server.port=9001

spring.application.name=langchain4j-01helloworld

package com.atguigu.study.config;

import dev.langchain4j.model.chat.ChatModel;
import dev.langchain4j.model.openai.OpenAiChatModel;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @auther zzyybs@126.com
 * @Date 2025-05-27 22:04
 * @Description: 知识出处 https://docs.langchain4j.dev/get-started
 */
@Configuration
public class LLMConfig {
    @Bean
    public ChatModel chatModelQwen()
    {
        return OpenAiChatModel.builder()
                        .apiKey(System.getenv("aliQwen-api"))  // 注意：这里api-key放在本地环境变量中
                        .modelName("qwen-plus")
                        .baseUrl("https://dashscope.aliyuncs.com/compatible-mode/v1")
                .build();
    }

}

package com.atguigu.study.controller;

import dev.langchain4j.model.chat.ChatModel;
import dev.langchain4j.model.openai.OpenAiChatModel;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @auther zzyybs@126.com
 * @Date 2025-05-27 21:43
 * @Description: TODO
 */
@RestController
@Slf4j
public class HelloLangChain4JController
{
    @Resource
    private ChatModel chatModelQwen;

    // http://localhost:9001/langchain4j/hello?prompt=如何学习java
    @GetMapping(value = "/langchain4j/hello")
    public String hello(@RequestParam(value = "prompt", defaultValue = "你是谁") String prompt)
    {
        String result = chatModelQwen.chat(prompt);

        System.out.println("通过langchain4j调用模型返回结果：\n"+result);

        return result;
    }
}

测试：

http://localhost:9001/langchain4j/hello?question=如何学习mysql

如果保证多种大模型在系统里共存

DeepSeek

https://platform.deepseek.com/usage

API文档

https://api-docs.deepseek.com/zh-cn/

创建Module

<?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>
    <parent>
        <groupId>com.atguigu.stduy</groupId>
        <artifactId>langchain4j-atguiguV5</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>langchain4j-02multi-model-together</artifactId>
    <name>langchain4j-02multi-model-together多模型共存</name>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--langchain4j-open-ai 基础-->
        <!--所有调用均基于 OpenAI 协议标准，实现一致的接口设计与规范LangChain4j 提供与许多 LLM 提供商的集成
        从最简单的开始方式是从 OpenAI 集成开始https://docs.langchain4j.dev/get-started    -->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai</artifactId>
        </dependency>
        <!--langchain4j 高阶-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

配置类

package com.atguigu.study.config;

import dev.langchain4j.model.chat.ChatModel;
import dev.langchain4j.model.openai.OpenAiChatModel;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @auther zzyybs@126.com
 * @Date 2025-05-27 22:04
 * @Description: 知识出处 https://docs.langchain4j.dev/get-started
 */
@Configuration
public class LLMConfig
{
    @Bean(name = "qwen")
    public ChatModel chatModelQwen()
    {
        return OpenAiChatModel.builder()
                    .apiKey(System.getenv("aliQwen-api"))
                    .modelName("qwen-plus")
                    .baseUrl("https://dashscope.aliyuncs.com/compatible-mode/v1")
                .build();
    }

    /**
    * @Description: 知识出处，https://api-docs.deepseek.com/zh-cn/
    * @Auther: zzyybs@126.com
    */
    @Bean(name = "deepseek")
    public ChatModel chatModelDeepSeek()
    {
        return  OpenAiChatModel.builder()
                        .apiKey(System.getenv("deepseek-api"))
                        .modelName("deepseek-chat")
                        //.modelName("deepseek-reasoner")
                        .baseUrl("https://api.deepseek.com/v1")
                .build();
    }
}

package com.atguigu.study.controller;

import dev.langchain4j.model.chat.ChatModel;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @auther zzyybs@126.com
 * @Date 2025-05-28 11:27
 * @Description: TODO
 */
@RestController
@Slf4j
public class MultiModelController
{
    @Resource(name = "qwen")
    private ChatModel chatModelQwen;

    @Resource(name = "deepseek")
    private ChatModel chatModelDeepSeek;

    // http://localhost:9002/multimodel/qwen
    @GetMapping(value = "/multimodel/qwen")
    public String qwenCall(@RequestParam(value = "prompt", defaultValue = "你是谁") String prompt)
    {
        String result = chatModelQwen.chat(prompt);

        System.out.println("通过langchain4j调用模型返回结果：\n"+result);

        return result;
    }

    // http://localhost:9002/multimodel/deepseek
    @GetMapping(value = "/multimodel/deepseek")
    public String deepseekCall(@RequestParam(value = "prompt", defaultValue = "你是谁") String prompt)
    {
        String result = chatModelDeepSeek.chat(prompt);

        System.out.println("通过langchain4j调用模型返回结果：\n"+result);

        return result;
    }
}

3.LangChain4J整合Springboot

https://docs.langchain4j.dev/tutorials/spring-boot-integration

SpringBoot整合低阶API

SpringBoot整合高阶API

LangChain4J原生整合

LangChain4J-Boot整合

总结

开发

创建Module

langchain4j-03boot-integration

pom

<?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>
    <parent>
        <groupId>com.atguigu.stduy</groupId>
        <artifactId>langchain4j-atguiguV5</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>langchain4j-03boot-integration</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--langchain4j原生 基础-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai</artifactId>
        </dependency>
        <!--langchain4j原生 高阶-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j</artifactId>
        </dependency>
        <!--1 LangChain4j 整合boot底层支持-->
        <!--   https://docs.langchain4j.dev/tutorials/spring-boot-integration  -->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-open-ai-spring-boot-starter</artifactId>
        </dependency>
        <!--2 LangChain4j 整合boot高阶支持-->
        <dependency>
            <groupId>dev.langchain4j</groupId>
            <artifactId>langchain4j-spring-boot-starter</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

配置

server.port=9003

spring.application.name=langchain4j-12boot-integration

# https://docs.langchain4j.dev/tutorials/spring-boot-integration
langchain4j.open-ai.chat-model.api-key=${aliQwen-api}
langchain4j.open-ai.chat-model.model-name=qwen-plus
langchain4j.open-ai.chat-model.base-url=https://dashscope.aliyuncs.com/compatible-mode/v1

低阶API

package com.atguigu.study.controller;

import dev.langchain4j.model.chat.ChatModel;
import jakarta.annotation.Resource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @auther zzyybs@126.com
 * @Date 2025-06-18 15:43
 * @Description: TODO
 */
@RestController
public class PopularIntegrationController
{
    @Resource
    private ChatModel chatModel;

    // http://localhost:9003/lc4j/boot/chat
    @GetMapping(value = "/lc4j/boot/chat")
    public String chat(@RequestParam(value = "prompt", defaultValue = "你是谁") String prompt)
    {
        return chatModel.chat(prompt);
    }
}

高阶API

自定义一个接口并添加注解@AiService

package com.atguigu.study.service;

import dev.langchain4j.service.spring.AiService;

/**
 * @auther zzyybs@126.com
 * @Date 2025-06-18 15:40
 * @Description: 知识出处，https://docs.langchain4j.dev/tutorials/spring-boot-integration/#spring-boot-starter-for-declarative-ai-services
 */
@AiService
public interface ChatAssistant
{
    String chat(String prompt);
}
 

package com.atguigu.study.controller;

import com.atguigu.study.service.ChatAssistant;
import jakarta.annotation.Resource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @auther zzyybs@126.com
 * @Date 2025-06-18 15:43
 * @Description: TODO
 */
@RestController
public class DeclarativeAIServiceController
{
    @Resource
    private ChatAssistant chatAssistantQwen;


   // http://localhost:9003/lc4j/boot/declarative
    @GetMapping(value = "/lc4j/boot/declarative")
    public String declarative(@RequestParam(value = "prompt", defaultValue = "你是谁") String prompt)
    {
        return chatAssistantQwen.chat(prompt);
    }
}