longchain4j 学习系列(4)-mcp调用

1 <dependency>
2     <groupId>dev.langchain4j</groupId>
3     <artifactId>langchain4j-mcp</artifactId>
4     <version>1.1.0-beta7</version>
5 </dependency>

/**
 * 初始化SSE客户端
 *
 * @param sseUrl SSE服务器连接地址
 * @return McpClient实例
 */
private static McpClient initSseClient(String sseUrl) {
    // 构建默认MCP客户端
    return new DefaultMcpClient.Builder()
            .clientName("yjmyzz.cnblogs.com")
            .protocolVersion("2024-11-05")
            .toolExecutionTimeout(Duration.ofSeconds(10))
            // 配置HTTP传输层参数
            .transport(new HttpMcpTransport.Builder()
                    // 设置SSE服务器连接URL
                    .sseUrl(sseUrl)
                    // 设置连接超时时间
                    .timeout(Duration.ofSeconds(10))
                    // 启用请求日志记录
                    .logRequests(true)
                    // 启用响应日志记录
                    .logResponses(true)
                    .build())
            .build();
}

    private interface Assistant {
        String chat(String userMessage);
    }

    /**
     * 直接获取订单状态信息
     *
     * @param orderId 订单ID，用于查询指定订单的状态
     * @return ResponseEntity<String> 包含订单状态信息的响应实体，成功时返回订单状态JSON字符串，
     * 失败时返回包含错误信息的JSON字符串
     */
    @GetMapping(value = "/order", produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<String> getOrderStatusDirect(@RequestParam String orderId) {
        McpClient mcpClient = null;
        try {
            // 初始化SSE客户端连接
            mcpClient = initSseClient("http://localhost:8070/sse");

            // 构建AI助手服务，配置聊天模型和工具提供者
            Assistant assistant = AiServices.builder(Assistant.class)
                    .chatModel(deepSeekChatModel)
                    .toolProvider(McpToolProvider.builder().mcpClients(mcpClient).build())
                    .build();

            // 调用AI助手查询订单状态
            String response = assistant.chat("查询订单状态，订单号：" + orderId);
            return ResponseEntity.ok(response);
        } catch (Exception e) {
            log.error("查询订单状态时发生错误", e);
            return ResponseEntity.ok("{\"error\":\"查询订单状态失败: " + e.getMessage() + "\"}");
        } finally {
            // 确保MCP客户端连接被正确关闭
            if (mcpClient != null) {
                try {
                    mcpClient.close();
                } catch (Exception e) {
                    log.error("关闭MCP客户端时发生错误", e);
                }
            }
        }
    }

2025-10-03T20:30:43.277+08:00  INFO 18312 --- [longchain4j-study] [nio-8080-exec-2] d.l.http.client.log.LoggingHttpClient    : HTTP request:
- method: POST
- url: https://api.deepseek.com/chat/completions
- headers: [Authorization: Beare...00], [User-Agent: langchain4j-openai], [Content-Type: application/json]
- body: {
  "model" : "deepseek-chat",
  "messages" : [ {
    "role" : "user",
    "content" : "查询订单状态，订单号：25070602"
  } ],
  "temperature" : 0.7,
  "stream" : false,
  "max_tokens" : 2048,
  "tools" : [ {
    "type" : "function",
    "function" : {
      "name" : "queryOrderStatus",
      "description" : "根据订单号查询订单状态",
      "parameters" : {
        "type" : "object",
        "properties" : {
          "orderNo" : {
            "type" : "string",
            "description" : "订单号,格式为8位数字,比如：25070601"
          }
        },
        "required" : [ "orderNo" ]
      }
    }
  } ]
}

...

2025-10-03T20:30:45.770+08:00  INFO 18312 --- [longchain4j-study] [nio-8080-exec-2] d.l.http.client.log.LoggingHttpClient    : HTTP request:
- method: POST
- url: https://api.deepseek.com/chat/completions
- headers: [Authorization: Beare...00], [User-Agent: langchain4j-openai], [Content-Type: application/json]
- body: {
  "model" : "deepseek-chat",
  "messages" : [ {
    "role" : "user",
    "content" : "查询订单状态，订单号：25070602"
  }, {
    "role" : "assistant",
    "content" : "我来帮您查询订单号为25070602的订单状态。",
    "tool_calls" : [ {
      "id" : "call_00_QnwEmctjY5kaQf5MEQ5C2i9Y",
      "type" : "function",
      "function" : {
        "name" : "queryOrderStatus",
        "arguments" : "{\"orderNo\": \"25070602\"}"
      }
    } ]
  }, {
    "role" : "tool",
    "tool_call_id" : "call_00_QnwEmctjY5kaQf5MEQ5C2i9Y",
    "content" : "\"订单号：25070602，订单状态：已完成\""
  } ],
  "temperature" : 0.7,
  "stream" : false,
  "max_tokens" : 2048,
  "tools" : [ {
    "type" : "function",
    "function" : {
      "name" : "queryOrderStatus",
      "description" : "根据订单号查询订单状态",
      "parameters" : {
        "type" : "object",
        "properties" : {
          "orderNo" : {
            "type" : "string",
            "description" : "订单号,格式为8位数字,比如：25070601"
          }
        },
        "required" : [ "orderNo" ]
      }
    }
  } ]
}