How can I split a usable MCP URL into the ​​baseUri​​ and ​​sseEndpoint​​ required by Spring AI's ​​HttpClientSseClientTransport​​?

[xiangshengyun]

Bug description
I can successfully connect to my MCP server using the URL "http://localhost:3000/mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01" with the local open-source tool MCP Inspector(https://github.com/modelcontextprotocol/inspector).
However, I cannot connect to the same URL with the Spring AI SDK because I don’t know how to split it into baseUri and sseEndpoint.
BTW , "cf9ec4527e3c4a2cbb149a85ea45ab01" is one of my multiple MCP server UUIDs.
Waiting for your help—I’d really appreciate it!

Environment
java.version: 17
spring-ai version : 1.1.0-SNAPSHOT

Steps to reproduce
I tried different cases as below:

1. "http://localhost:3000" and "/mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01"
   2025/07/29 19:55:01.074 [ForkJoinPool.commonPool-worker-1] WARN i.m.client.LifecycleInitializer-288 - Failed to initialize java.lang.RuntimeException: Sending message failed with a non-OK HTTP code: 404 - No transport found for sessionId at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$sendMessage$9(HttpClientSseClientTransport.java:426) at reactor.core.publisher.FluxHandle$HandleSubscriber.onNext(FluxHandle.java:113)
   ... ....
   Caused by: io.modelcontextprotocol.spec.McpError: Client failed to initialize by explicit API call at io.modelcontextprotocol.client.LifecycleInitializer.lambda$withIntitialization$2(LifecycleInitializer.java:289) at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:94)

2. "http://localhost:3000/mcp-hub" and "/sse/cf9ec4527e3c4a2cbb149a85ea45ab01"
   2025/07/29 19:57:37.299 [HttpClient-1-Worker-0] ERROR reactor.core.publisher.Operators-324 - Operator called default onErrorDropped reactor.core.Exceptions$ErrorCallbackNotImplemented: io.modelcontextprotocol.spec.McpError: Invalid SSE response. Status code: 404 Line: {"error_msg":"404 Route Not Found"} Caused by: io.modelcontextprotocol.spec.McpError: Invalid SSE response. Status code: 404 Line: {"error_msg":"404 Route Not Found"} at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:173) at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:67)
   Invalid SSE response. Status code: 404 Line: {"error_msg":"404 Route Not Found"}

3. "http://localhost:3000/mcp-hub/sse" and "/cf9ec4527e3c4a2cbb149a85ea45ab01"
   The error messages were the same as in Case 2.

My Code
`
public static McpSyncClient buildSyncMcpClientTransport(MCPServerInfo mcpServerInfo) {

HttpClient.Builder clientBuilder = HttpClient.newBuilder();
clientBuilder.connectTimeout(Duration.ofSeconds(10));
McpClientTransport transport = HttpClientSseClientTransport
        .builder(mcpServerInfo.getBaseUri())
        .sseEndpoint(mcpServerInfo.getSseEndpoint())
        .clientBuilder(clientBuilder)
        .objectMapper(new ObjectMapper())
        .build();
NamedClientMcpTransport namedTransport = new NamedClientMcpTransport(mcpServerInfo.getName(), transport);
McpSyncClient mcpClient = McpClient.sync(namedTransport.transport())
        .clientInfo(new McpSchema.Implementation("client-name", "1.0.0"))
        .requestTimeout(Duration.ofSeconds(15)).build();
try {
    mcpClient.initialize();
} catch (Exception e) {
    log.error("SSE initialization failed: URI={}, Endpoint={}, Error={}",
            mcpServerInfo.getBaseUri(), mcpServerInfo.getSseEndpoint(), e.getMessage());
    throw new RuntimeException("SSE connection failed, please check server status or configuration", e);
}

ToolCallbackProvider provider = new SyncMcpToolCallbackProvider(mcpClient);
ToolCallback[] tools = provider.getToolCallbacks();
try {
    ObjectMapper mapper = new ObjectMapper();
    String jsonString = mapper.writeValueAsString(tools);
    log.debug("Original MCP tool list: {}", jsonString);
    
} catch (JsonProcessingException e) {
    throw new RuntimeException(e);
}
return mcpClient;

}
`
BTW I can succesfully connect to amap mcp server with above spring ai code .
"baseUri": "https://mcp.amap.com", "sseEndpoint": "/sse?key=mykey",

[wilocu]

take

[xiangshengyun]

@wilocu Appreciated! The issue is solved. Thanks for your contribution.As you mentioned, the following URL segmentation is correct:
"http://localhost:3000/" and "/mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01"

BTW: The HTTP 404 error - "No transport found for sessionId" was caused by my unstable MCP server（When I call Listtools, the issue shown in the image below occurs with a probability of over 70%, which has led to significant misdirection in my work）. Thank you again.

[xiangshengyun]

​​BTW:​​ If the error message "400 - TypeError: argument string is required"is returned for the request /sse/messages?sessionId=XX, you need to add the following code:
`// Set Content-Type header

requestBuilder.header("Content-Type", "application/json");`