Generate a complete Model Context Protocol server project in Java using the official MCP Java SDK with reactive streams and optional Spring Boot integration.
インストールする前に、エージェントに与えられる指示の中身を確認できます。
Generate a complete, production-ready MCP server in Java using the official Java SDK with Maven or Gradle.
When asked to create a Java MCP server, generate a complete project with this structure:
my-mcp-server/
├── pom.xml (or build.gradle.kts)
├── src/
│ ├── main/
│ │ ├── java/
│ │ │ └── com/example/mcp/
│ │ │ ├── McpServerApplication.java
│ │ │ ├── config/
│ │ │ │ └── ServerConfiguration.java
│ │ │ ├── tools/
│ │ │ │ ├── ToolDefinitions.java
│ │ │ │ └── ToolHandlers.java
│ │ │ ├── resources/
│ │ │ │ ├── ResourceDefinitions.java
│ │ │ │ └── ResourceHandlers.java
│ │ │ └── prompts/
│ │ │ ├── PromptDefinitions.java
│ │ │ └── PromptHandlers.java
│ │ └── resources/
│ │ └── application.properties (if using Spring)
│ └── test/
│ └── java/
│ └── com/example/mcp/
│ └── McpServerTest.java
└── README.md
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>my-mcp-server</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<name>My MCP Server</name>
<description>Model Context Protocol server implementation</description>
<properties>
<java.version>17</java.version>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<mcp.version>0.14.1</mcp.version>
<slf4j.version>2.0.9</slf4j.version>
<logback.version>1.4.11</logback.version>
<junit.version>5.10.0</junit.version>
</properties>
<dependencies>
<!-- MCP Java SDK -->
<dependency>
<groupId>io.modelcontextprotocol.sdk</groupId>
<artifactId>mcp</artifactId>
<version>${mcp.version}</version>
</dependency>
<!-- Logging -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>${logback.version}</version>
</dependency>
<!-- Testing -->
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.11.0</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.1.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.5.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>com.example.mcp.McpServerApplication</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
plugins {
id("java")
id("application")
}
group = "com.example"
version = "1.0.0"
java {
sourceCompatibility = JavaVersion.VERSION_17
targetCompatibility = JavaVersion.VERSION_17
}
repositories {
mavenCentral()
}
dependencies {
// MCP Java SDK
implementation("io.modelcontextprotocol.sdk:mcp:0.14.1")
// Logging
implementation("org.slf4j:slf4j-api:2.0.9")
implementation("ch.qos.logback:logback-classic:1.4.11")
// Testing
testImplementation("org.junit.jupiter:junit-jupiter:5.10.0")
testImplementation("io.projectreactor:reactor-test:3.5.0")
}
application {
mainClass.set("com.example.mcp.McpServerApplication")
}
tasks.test {
useJUnitPlatform()
}
package com.example.mcp;
import com.example.mcp.tools.ToolHandlers;
import com.example.mcp.resources.ResourceHandlers;
import com.example.mcp.prompts.PromptHandlers;
import io.mcp.server.McpServer;
import io.mcp.server.McpServerBuilder;
import io.mcp.server.transport.StdioServerTransport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.Disposable;
public class McpServerApplication {
private static final Logger log = LoggerFactory.getLogger(McpServerApplication.class);
public static void main(String[] args) {
log.info("Starting MCP Server...");
try {
McpServer server = createServer();
StdioServerTransport transport = new StdioServerTransport();
// Start server
Disposable serverDisposable = server.start(transport).subscribe();
// Graceful shutdown
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
log.info("Shutting down MCP server");
serverDisposable.dispose();
server.stop().block();
}));
log.info("MCP Server started successfully");
// Keep running
Thread.currentThread().join();
} catch (Exception e) {
log.error("Failed to start MCP server", e);
System.exit(1);
}
}
private static McpServer createServer() {
McpServer server = McpServerBuilder.builder()
.serverInfo("my-mcp-server", "1.0.0")
.capabilities(capabilities -> capabilities
.tools(true)
.resources(true)
.prompts(true))
.build();
// Register handlers
ToolHandlers.register(server);
ResourceHandlers.register(server);
PromptHandlers.register(server);
return server;
}
}
package com.example.mcp.tools;
import io.mcp.json.JsonSchema;
import io.mcp.server.tool.Tool;
import java.util.List;
public class ToolDefinitions {
public static List<Tool> getTools() {
return List.of(
createGreetTool(),
createCalculateTool()
);
}
private static Tool createGreetTool() {
return Tool.builder()
.name("greet")
.description("Generate a greeting message")
.inputSchema(JsonSchema.object()
.property("name", JsonSchema.string()
.description("Name to greet")
.required(true)))
.build();
}
private static Tool createCalculateTool() {
return Tool.builder()
.name("calculate")
.description("Perform mathematical calculations")
.inputSchema(JsonSchema.object()
.property("operation", JsonSchema.string()
.description("Operation to perform")
.enumValues(List.of("add", "subtract", "multiply", "divide"))
.required(true))
.property("a", JsonSchema.number()
.description("First operand")
.required(true))
.property("b", JsonSchema.number()
.description("Second operand")
.required(true)))
.build();
}
}
package com.example.mcp.tools;
import com.fasterxml.jackson.databind.JsonNode;
import io.mcp.server.McpServer;
import io.mcp.server.tool.ToolResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
public class ToolHandlers {
private static final Logger log = LoggerFactory.getLogger(ToolHandlers.class);
public static void register(McpServer server) {
// Register tool list handler
server.addToolListHandler(() -> {
log.debug("Listing available tools");
return Mono.just(ToolDefinitions.getTools());
});
// Register greet handler
server.addToolHandler("greet", ToolHandlers::handleGreet);
// Register calculate handler
server.addToolHandler("calculate", ToolHandlers::handleCalculate);
}
private static Mono<ToolResponse> handleGreet(JsonNode arguments) {
log.info("Greet tool called");
if (!arguments.has("name")) {
return Mono.just(ToolResponse.error()
.message("Missing 'name' parameter")
.build());
}
String name = arguments.get("name").asText();
String greeting = "Hello, " + name + "! Welcome to MCP.";
log.debug("Generated greeting for: {}", name);
return Mono.just(ToolResponse.success()
.addTextContent(greeting)
.build());
}
private static Mono<ToolResponse> handleCalculate(JsonNode arguments) {
log.info("Calculate tool called");
if (!arguments.has("operation") || !arguments.has("a") || !arguments.has("b")) {
return Mono.just(ToolResponse.error()
.message("Missing required parameters")
.build());
}
String operation = arguments.get("operation").asText();
double a = arguments.get("a").asDouble();
double b = arguments.get("b").asDouble();
double result;
switch (operation) {
case "add":
result = a + b;
break;
case "subtract":
result = a - b;
break;
case "multiply":
result = a * b;
break;
case "divide":
if (b == 0) {
return Mono.just(ToolResponse.error()
.message("Division by zero")
.build());
}
result = a / b;
break;
default:
return Mono.just(ToolResponse.error()
.message("Unknown operation: " + operation)
.build());
}
log.debug("Calculation: {} {} {} = {}", a, operation, b, result);
return Mono.just(ToolResponse.success()
.addTextContent("Result: " + result)
.build());
}
}
package com.example.mcp.resources;
import io.mcp.server.resource.Resource;
import java.util.List;
public class ResourceDefinitions {
public static List<Resource> getResources() {
return List.of(
Resource.builder()
.name("Example Data")
.uri("resource://data/example")
.description("Example resource data")
.mimeType("application/json")
.build(),
Resource.builder()
.name("Configuration")
.uri("resource://config")
.description("Server configuration")
.mimeType("application/json")
.build()
);
}
}
package com.example.mcp.resources;
import io.mcp.server.McpServer;
import io.mcp.server.resource.ResourceContent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
import java.time.Instant;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class ResourceHandlers {
private static final Logger log = LoggerFactory.getLogger(ResourceHandlers.class);
private static final Map<String, Boolean> subscriptions = new ConcurrentHashMap<>();
public static void register(McpServer server) {
// Register resource list handler
server.addResourceListHandler(() -> {
log.debug("Listing available resources");
return Mono.just(ResourceDefinitions.getResources());
});
// Register resource read handler
server.addResourceReadHandler(ResourceHandlers::handleRead);
// Register resource subscribe handler
server.addResourceSubscribeHandler(ResourceHandlers::handleSubscribe);
// Register resource unsubscribe handler
server.addResourceUnsubscribeHandler(ResourceHandlers::handleUnsubscribe);
}
private static Mono<ResourceContent> handleRead(String uri) {
log.info("Reading resource: {}", uri);
switch (uri) {
case "resource://data/example":
String jsonData = String.format(
"{\"message\":\"Example resource data\",\"timestamp\":\"%s\"}",
Instant.now()
);
return Mono.just(ResourceContent.text(jsonData, uri, "application/json"));
case "resource://config":
String config = "{\"serverName\":\"my-mcp-server\",\"version\":\"1.0.0\"}";
return Mono.just(ResourceContent.text(config, uri, "application/json"));
default:
log.warn("Unknown resource requested: {}", uri);
return Mono.error(new IllegalArgumentException("Unknown resource URI: " + uri));
}
}
private static Mono<Void> handleSubscribe(String uri) {
log.info("Client subscribed to resource: {}", uri);
subscriptions.put(uri, true);
return Mono.empty();
}
private static Mono<Void> handleUnsubscribe(String uri) {
log.info("Client unsubscribed from resource: {}", uri);
subscriptions.remove(uri);
return Mono.empty();
}
}
package com.example.mcp.prompts;
import io.mcp.server.prompt.Prompt;
import io.mcp.server.prompt.PromptArgument;
import java.util.List;
public class PromptDefinitions {
public static List<Prompt> getPrompts() {
return List.of(
Prompt.builder()
.name("code-review")
.description("Generate a code review prompt")
.argument(PromptArgument.builder()
.name("language")
.description("Programming language")
.required(true)
.build())
.argument(PromptArgument.builder()
.name("focus")
.description("Review focus area")
.required(false)
.build())
.build()
);
}
}
package com.example.mcp.prompts;
import io.mcp.server.McpServer;
import io.mcp.server.prompt.PromptMessage;
import io.mcp.server.prompt.PromptResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
import java.util.List;
import java.util.Map;
public class PromptHandlers {
private static final Logger log = LoggerFactory.getLogger(PromptHandlers.class);
public static void register(McpServer server) {
// Register prompt list handler
server.addPromptListHandler(() -> {
log.debug("Listing available prompts");
return Mono.just(PromptDefinitions.getPrompts());
});
// Register prompt get handler
server.addPromptGetHandler(PromptHandlers::handleCodeReview);
}
private static Mono<PromptResult> handleCodeReview(String name, Map<String, String> arguments) {
log.info("Getting prompt: {}", name);
if (!name.equals("code-review")) {
return Mono.error(new IllegalArgumentException("Unknown prompt: " + name));
}
String language = arguments.getOrDefault("language", "Java");
String focus = arguments.getOrDefault("focus", "general quality");
String description = "Code review for " + language + " with focus on " + focus;
List<PromptMessage> messages = List.of(
PromptMessage.user("Please review this " + language + " code with focus on " + focus + "."),
PromptMessage.assistant("I'll review the code focusing on " + focus + ". Please share the code."),
PromptMessage.user("Here's the code to review: [paste code here]")
);
log.debug("Generated code review prompt for {} ({})", language, focus);
return Mono.just(PromptResult.builder()
.description(description)
.messages(messages)
.build());
}
}
package com.example.mcp;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import io.mcp.server.McpServer;
import io.mcp.server.McpSyncServer;
import io.mcp.server.tool.ToolResponse;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class McpServerTest {
private McpSyncServer syncServer;
private ObjectMapper objectMapper;
@BeforeEach
void setUp() {
McpServer server = createTestServer();
syncServer = server.toSyncServer();
objectMapper = new ObjectMapper();
}
private McpServer createTestServer() {
// Same setup as main application
McpServer server = McpServerBuilder.builder()
.serverInfo("test-server", "1.0.0")
.capabilities(cap -> cap.tools(true))
.build();
// Register handlers
ToolHandlers.register(server);
return server;
}
@Test
void testGreetTool() {
ObjectNode args = objectMapper.createObjectNode();
args.put("name", "Java");
ToolResponse response = syncServer.callTool("greet", args);
assertFalse(response.isError());
assertEquals(1, response.getContent().size());
assertTrue(response.getContent().get(0).getText().contains("Java"));
}
@Test
void testCalculateTool() {
ObjectNode args = objectMapper.createObjectNode();
args.put("operation", "add");
args.put("a", 5);
args.put("b", 3);
ToolResponse response = syncServer.callTool("calculate", args);
assertFalse(response.isError());
assertTrue(response.getContent().get(0).getText().contains("8"));
}
@Test
void testDivideByZero() {
ObjectNode args = objectMapper.createObjectNode();
args.put("operation", "divide");
args.put("a", 10);
args.put("b", 0);
ToolResponse response = syncServer.callTool("calculate", args);
assertTrue(response.isError());
}
}
# My MCP Server
A Model Context Protocol server built with Java and the official MCP Java SDK.
## Features
- ✅ Tools: greet, calculate
- ✅ Resources: example data, configuration
- ✅ Prompts: code-review
- ✅ Reactive Streams with Project Reactor
- ✅ Structured logging with SLF4J
- ✅ Full test coverage
## Requirements
- Java 17 or later
- Maven 3.6+ or Gradle 7+
## Build
### Maven
```bash
mvn clean package
./gradlew build
java -jar target/my-mcp-server-1.0.0.jar
./gradlew run
mvn test
./gradlew test
Add to claude_desktop_config.json:
{
"mcpServers": {
"my-mcp-server": {
"command": "java",
"args": ["-jar", "/path/to/my-mcp-server-1.0.0.jar"]
}
}
}
MIT
## Generation Instructions
1. **Ask for project name and package**
2. **Choose build tool** (Maven or Gradle)
3. **Generate all files** with proper package structure
4. **Use Reactive Streams** for async handlers
5. **Include comprehensive logging** with SLF4J
6. **Add tests** for all handlers
7. **Follow Java conventions** (camelCase, PascalCase)
8. **Include error handling** with proper responses
9. **Document public APIs** with Javadoc
10. **Provide both sync and async** examples
まだレビューはありません。使ってみた感想をお寄せください。
概要と使いどころ
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日本語の概要は準備中です。原文の説明を表示しています。
Use this skill when the user explicitly asks to map, document, or onboard into an existing codebase. Trigger for prompts like "map this codebase", "document this architecture", "onboard me to this repo", or "create codebase docs". Do not trigger for routine feature implementation, bug fixes, or narrow code edits unless the user asks for repository-level discovery.
日本語の概要は準備中です。原文の説明を表示しています。
Act on user feedback attached to the current session. Use when the user submits feedback on the session's changes via the Submit Feedback button.
日本語の概要は準備中です。原文の説明を表示しています。
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日本語の概要は準備中です。原文の説明を表示しています。
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日本語の概要は準備中です。原文の説明を表示しています。
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日本語の概要は準備中です。原文の説明を表示しています。