jeecgboot/JeecgBoot · warning · RuntimeException

未知方法: {method}

Error message

未知方法: {method}

What it means

McpDemoController implements a minimal MCP (Model Context Protocol) JSON-RPC 2.0 server. The switch dispatches only initialize, initialized, notifications/initialized, tools/list, tools/call, ping, notifications/cancelled. Any other method -- that is not a notifications/* (which is silently ignored) -- throws. The exception is caught and returned to the client as JSON-RPC error code -32603 (internal error) with the method name in the message.

Source

Thrown at jeecg-boot/jeecg-boot-module/jeecg-module-demo/src/main/java/org/jeecg/modules/demo/mcp/McpDemoController.java:184

            // 构建 JSON-RPC 2.0 响应
            Map<String, Object> jsonRpcResponse = new LinkedHashMap<>();
            jsonRpcResponse.put("jsonrpc", "2.0");
            jsonRpcResponse.put("id", id);
            
            try {
                Object result = switch (method) {
                    case "initialize" -> handleInitialize(params);
                    case "initialized", "notifications/initialized" -> handleInitialized();
                    case "tools/list" -> handleToolsList();
                    case "tools/call" -> handleToolsCall(params);
                    case "ping" -> handlePing();
                    case "notifications/cancelled" -> handleCancelled(params);
                    default -> {
                        if (method != null && method.startsWith("notifications/")) {
                            log.info("[MCP Server] 忽略未知通知: {}", method);
                            yield Map.of();
                        }
                        throw new RuntimeException("未知方法: " + method);
                    }
                };
                jsonRpcResponse.put("result", result);
            } catch (Exception e) {
                log.error("[MCP Server] 处理请求失败", e);
                jsonRpcResponse.put("error", Map.of(
                        "code", -32603,
                        "message", e.getMessage()
                ));
            }
            
            String responseJson = JSON.toJSONString(jsonRpcResponse);
            log.info("[MCP Server] 返回: {}", responseJson);
            writer.write(responseJson);
            
        } catch (Exception e) {
            log.error("[MCP Server] 解析请求失败", e);
            writer.write("{\"jsonrpc\":\"2.0\",\"id\":null,\"error\":{\"code\":-32700,\"message\":\"Parse error\"}}");

View on GitHub (pinned to 96fb33f5ec)

Solutions

1. Check the 'method' field in the request and the log line '[MCP Server] 处理请求失败'.
2. If the client needs the capability, add a case branch and a handler.
3. If it is a notification, ensure the method starts with 'notifications/' so it is ignored instead of erroring.
4. Return a proper -32601 'method not found' instead of -32603 if you want spec-correct behavior.

Example fix

// before
default -> throw new RuntimeException("未知方法: " + method);
// after - spec-correct JSON-RPC method-not-found
default -> {
    if (method != null && method.startsWith("notifications/")) { yield Map.of(); }
    throw new RuntimeException("Method not found: " + method); // map to code -32601
}

private static final Set<String> SUPPORTED = Set.of(
    "initialize","initialized","notifications/initialized",
    "tools/list","tools/call","ping","notifications/cancelled");
if (method != null && !SUPPORTED.contains(method) && !method.startsWith("notifications/")) {
    // return JSON-RPC -32601 method not found instead of -32603
}

// The handler already catches Exception and maps to error code -32603.
// Improve: distinguish method-not-found (-32601) from internal errors.
try { ... } catch (UnsupportedMethodException e) {
    jsonRpcResponse.put("error", Map.of("code", -32601, "message", e.getMessage()));
} catch (Exception e) {
    jsonRpcResponse.put("error", Map.of("code", -32603, "message", e.getMessage()));
}

When it happens

Trigger: An MCP client sends a method the demo server doesn't implement: resources/*, prompts/*, completion/*, logging/*, or any future-spec method.

Common situations: Client uses newer MCP spec capabilities the demo lacks; a generic MCP client probing endpoints; custom method invocation.

Related errors

• 不支持的运算符: {op}
• 未知工具: {toolName}
• 模板缺少参数：${item}
• The file name can not null
• 非法存储路径，路径包含遍历字符: {storePath}

AI-assisted analysis of jeecgboot/JeecgBoot@96fb33f5ec (2026-08-14). Data as JSON: /api/errors/fb206021d7195c2c. Report an issue: GitHub.