MCP Server Java Sse Http Demo

🚀 Weather Java SSE Transmission MCP Service

This is a working example implementing the Model Context Protocol (MCP) Java SDK. It includes a fast - agent for interacting with the Weather mcp - server.

⚠️ Important Note

This is not production - grade code. It is merely to demonstrate how to build a complete end - to - end solution that can utilize multiple MCP servers (local Stdio transmission and remote HTTP SSE transmission). Additionally, it avoids excessive use of the Spring framework to meet the needs of users who do not wish to use Spring.

In the demonstration, you will see the agent:

1. Use Claude Sonnet 3.7 throughout the process to handle the large language model (LLM) part.
2. Call the "fetch" web search tool on the MCP server to find the latitude and longitude corresponding to each input city.
3. Then use these latitude and longitude values to call the weather MCP server tool (implemented in this repository). You can see the detailed information of the call in the upper half of the terminal window.
4. Summarize the weather forecasts of each city and determine which city will be the warmest tomorrow.

The agent automatically decides which tools to call based on the context of the user - input prompt.

• Model Context Protocol (MCP)
• Java SDK
• List of MCP Servers

🚀 Quick Start

📦 Installation

Build and Start the Weather MCP Server

mvn clean package
java -jar mcp-server/target/mcp-server-1.0-SNAPSHOT.jar

Install, Configure and Start the fast - agent

Install

pip install uv
uv pip install fast - agent - mcp
uv run agent.py

Configure Claude and OpenAI API Keys

Copy the template file and edit it:

cp fastagent.secrets.yaml.TEMPLATE fastagent.secrets.yaml

Then add your API keys to this configuration file.

Note: Weather MCP Server Configuration

In fastagent.config.yaml, we have specified the available MCP servers for the agent. In this example, our server uses SSE HTTP transmission, which enables calling remote MCP servers:

mcp:
    servers:
        weather:
            transport: "sse"
            read_timeout_seconds: 10
            url: "http://localhost:8080/sse"

💻 Usage Examples

Low - Level Testing

Connect to the SSE stream:

curl -v -H "Accept: text/event - stream" "http://localhost:8080/sse"

Send a message to /mcp/messages (Note: include the sessionId obtained from SSE):

curl -X POST "http://localhost:8080/mcp/message?sessionId=b64ad193 - 6bb3 - 4e2e - b33c - 27a23011acb4" -d '{"hi": "mynameis"}' | jq .

📚 Documentation

• youngsu5582's MCP Server MySQL Implementation