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知识体系——MCP（四）demo（2）开发mcp client

news 2026/5/12 12:35:32

下面使用io.modelcontextprotocol.sdk自定义开发mcp client。

一、demo

1、pom

<?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.demo</groupId> <artifactId>security-ai-mcp-client-demo</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <name>security-ai-mcp-client-demo</name> <description>MCP Client demo: call security-ai-mcp-demo server via io.modelcontextprotocol.sdk</description> <properties> <java.version>17</java.version> <maven.compiler.source>17</maven.compiler.source> <maven.compiler.target>17</maven.compiler.target> <mcp.version>0.12.1</mcp.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>io.modelcontextprotocol.sdk</groupId> <artifactId>mcp-bom</artifactId> <version>${mcp.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>io.modelcontextprotocol.sdk</groupId> <artifactId>mcp</artifactId> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-simple</artifactId> <version>2.0.9</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>3.3.0</version> <configuration> <archive> <manifest> <mainClass>com.demo.mcp.client.SecurityAiMcpClientDemo</mainClass> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> </manifest> </archive> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <version>3.6.0</version> <executions> <execution> <id>copy-dependencies</id> <phase>package</phase> <goals> <goal>copy-dependencies</goal> </goals> <configuration> <outputDirectory>${project.build.directory}/lib</outputDirectory> </configuration> </execution> </executions> </plugin> </plugins> </build> </project>

2、实现

package com.demo.mcp.client; import io.modelcontextprotocol.client.McpClient; import io.modelcontextprotocol.client.McpSyncClient; import io.modelcontextprotocol.client.transport.ServerParameters; import io.modelcontextprotocol.client.transport.StdioClientTransport; import io.modelcontextprotocol.spec.McpSchema; import java.nio.file.Path; import java.nio.file.Paths; import java.time.Duration; import java.util.List; import java.util.Map; /** * MCP Client 示例：使用 io.modelcontextprotocol.sdk 调用 security-ai-mcp-demo（stdio 模式）。 * 先 initialize，再 listTools，最后 callTool(school_list) 并打印结果。 */ public class SecurityAiMcpClientDemo { /** Server jar 路径，可通过 -Dmcp.server.jar=... 覆盖 */ private static final String DEFAULT_SERVER_JAR = "../security-ai-mcp-demo/target/security-ai-mcp-demo-1.0-SNAPSHOT.jar"; public static void main(String[] args) throws Exception { String serverJar = System.getProperty("mcp.server.jar", DEFAULT_SERVER_JAR); Path jarPath = Paths.get(serverJar).toAbsolutePath().normalize(); if (!jarPath.toFile().exists()) { System.err.println("Server jar 不存在: " + jarPath); System.err.println("请先构建 security-ai-mcp-demo 或设置 -Dmcp.server.jar=绝对路径"); System.exit(1); } ServerParameters params = ServerParameters.builder("java") .args("-jar", jarPath.toString()) .build(); McpSyncClient client = McpClient.sync(new StdioClientTransport(params)) .requestTimeout(Duration.ofSeconds(30)) .build(); client.initialize(); System.out.println("已连接 MCP Server，协议已初始化。\n"); // 列出工具 McpSchema.ListToolsResult listResult = client.listTools(); List<McpSchema.Tool> tools = listResult != null && listResult.tools() != null ? listResult.tools() : List.of(); System.out.println("工具数量: " + tools.size()); tools.forEach(t -> System.out.println(" - " + t.name() + ": " + t.description())); System.out.println(); // 调用 school_list（必带 appKey） McpSchema.CallToolRequest callReq = McpSchema.CallToolRequest.builder() .name("school_list") .arguments(Map.<String, Object>of( "appKey", "demo-key-001", "pageNum", 1, "pageSize", 5)) .build(); McpSchema.CallToolResult callResult = client.callTool(callReq); System.out.println("school_list 调用结果:"); System.out.println(" isError: " + callResult.isError()); if (callResult.content() != null && !callResult.content().isEmpty()) { callResult.content().forEach(c -> { if (c instanceof McpSchema.TextContent) { McpSchema.TextContent tc = (McpSchema.TextContent) c; System.out.println(" content: " + tc.text()); } }); } else if (callResult.isError()) { System.out.println(" error: " + callResult); } } }

3、测试

执行main方法，控制台打印：

[boundedElastic-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - MCP server starting. [boundedElastic-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - MCP server started [pool-4-thread-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - STDERR Message received: 2026-03-11 11:04:11.187 [main] INFO c.demo.mcp.SecurityAiMcpApplication - Starting SecurityAiMcpApplication v1.0-SNAPSHOT using Java 21.0.8 with PID 26324 (C:\mydemo\security-ai-mcp-demo\target\security-ai-mcp-demo-1.0-SNAPSHOT.jar started by Tina.Zhang in C:\mydemo\ai-demo) [pool-4-thread-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - STDERR Message received: 2026-03-11 11:04:11.189 [main] INFO c.demo.mcp.SecurityAiMcpApplication - No active profile set, falling back to 1 default profile: "default" [pool-4-thread-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - STDERR Message received: 2026-03-11 11:04:12.107 [pool-2-thread-1] INFO i.m.server.McpAsyncServer - Client initialize request - Protocol: 2024-11-05, Capabilities: ClientCapabilities[experimental=null, roots=null, sampling=null, elicitation=null], Info: Implementation[name=Java SDK MCP Client, title=null, version=1.0.0] [pool-1-thread-1] INFO io.modelcontextprotocol.client.LifecycleInitializer - Server response with Protocol: 2024-11-05, Capabilities: ServerCapabilities[completions=null, experimental=null, logging=LoggingCapabilities[], prompts=null, resources=null, tools=ToolCapabilities[listChanged=true]], Info: Implementation[name=security-ai-mcp, title=null, version=1.0.0] and Instructions null 已连接 MCP Server，协议已初始化。 工具数量: 15 - user_list: 分页查询用户列表，支持按 account 模糊查询 - user_get: 根据 ID 获取用户 - user_save: 新增用户，body 为 UserEntity 的 JSON - user_update: 更新用户，body 为 UserEntity 的 JSON - user_delete: 根据 ID 删除用户 - school_list: 分页查询学校列表 - school_get: 根据 ID 获取学校 - school_save: 新增学校 - school_update: 更新学校 - school_delete: 根据 ID 删除学校 - role_list: 分页查询角色列表 - role_get: 根据 ID 获取角色 - role_save: 新增角色 - role_update: 更新角色 - role_delete: 根据 ID 删除角色 [pool-4-thread-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - STDERR Message received: 2026-03-11 11:04:12.299 [main] INFO c.demo.mcp.SecurityAiMcpApplication - Started SecurityAiMcpApplication in 1.644 seconds (process running for 2.232) [pool-4-thread-1] INFO io.modelcontextprotocol.client.transport.StdioClientTransport - STDERR Message received: 2026-03-11 11:04:12.303 [main] INFO com.demo.mcp.config.StdioMcpConfig - Server is ready. Waiting for JSON-RPC requests on stdin... school_list 调用结果: isError: false content: {"data":{"records":[{"id":1,"name":"第一中学","address":"北京市海淀区中关村大街1号"},{"id":2,"name":"第二中学","address":"北京市西城区西单北大街2号"},{"id":3,"name":"第三中学","address":"上海市浦东新区陆家嘴路3号"},{"id":4,"name":"实验小学","address":"广州市天河区体育西路4号"},{"id":5,"name":"育才中学","address":"深圳市南山区科技园路5号"}],"total":11,"size":5,"current":1,"pages":3},"code":200,"success":false}

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