langgraph4j笔记

版本：
jdk17
springboot # 3.3.5
langchain4j 0.34.0
langgraph4j # 1.8.17

引入依赖

langchain4j的依赖也是需要的，在此不赘述。

属性标签：<langgraph4j.version>1.8.17</langgraph4j.version><dependency><groupId>org.bsc.langgraph4j</groupId><artifactId>langgraph4j-core</artifactId><version>${langgraph4j.version}</version></dependency>

定义状态类

importorg.bsc.langgraph4j.state.AgentState;importjava.util.Map;publicclassMyCustomStateextendsAgentState{publicMyCustomState(Map<String,Object>initData){super(initData);}// 封装获取用户输入的方法，避免类型转换publicStringgetUserInput(){returnthis.<String>value("userInput").orElse("");}// 封装获取AI回复的方法publicStringgetAiResponse(){returnthis.<String>value("aiResponse").orElse("");}}

定义controller

run方法里面定义了一个langGraph，共两个节点，运行时会按照这个步骤走。

importcom.example.demo.entity.MyCustomState;importdev.langchain4j.model.chat.ChatLanguageModel;importorg.bsc.langgraph4j.CompiledGraph;importorg.bsc.langgraph4j.StateGraph;// 1. 导入异步节点动作接口importorg.bsc.langgraph4j.action.AsyncNodeAction;importorg.springframework.web.bind.annotation.GetMapping;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.RequestParam;importorg.springframework.web.bind.annotation.RestController;importjava.util.Map;importjava.util.Optional;importstaticorg.bsc.langgraph4j.GraphDefinition.START;importstaticorg.bsc.langgraph4j.GraphDefinition.END;// 2. 导入 node_async 静态方法，用于包装同步逻辑importstaticorg.bsc.langgraph4j.action.AsyncNodeAction.node_async;@RestController@RequestMapping("/api")publicclassLangGraph4jController{privatefinalChatLanguageModelchatLanguageModel;publicLangGraph4jController(ChatLanguageModelchatLanguageModel){this.chatLanguageModel=chatLanguageModel;}@GetMapping("/langgraph4j/run")publicStringrunGraph(@RequestParamStringmessage)throwsException{// 3. 使用 AsyncNodeAction 并配合 node_async 包装器AsyncNodeAction<MyCustomState>aiNode=node_async(state->{StringuserInput=state.value("userInput").map(Object::toString).orElse("");Stringresponse=chatLanguageModel.generate("请简短回答："+userInput);returnMap.of("aiResponse",response);});AsyncNodeAction<MyCustomState>formatNode=node_async(state->{StringaiResponse=state.value("aiResponse").map(Object::toString).orElse("");StringfinalResult=String.format("[格式化结果]: AI的最终回复是 -> %s",aiResponse);returnMap.of("aiResponse",finalResult);});// 4. 构建图StateGraph<MyCustomState>workflow=newStateGraph<>(MyCustomState::new).addNode("ai_processor",aiNode).addNode("formatter",formatNode).addEdge(START,"ai_processor").addEdge("ai_processor","formatter").addEdge("formatter",END);// 5. 编译并执行CompiledGraph<MyCustomState>graph=workflow.compile();Map<String,Object>initialState=Map.of("userInput",message);Optional<MyCustomState>finalStateOpt=graph.invoke(initialState);MyCustomStatefinalState=finalStateOpt.orElseThrow();returnfinalState.getAiResponse();}}

检查点 todo