Nicksxs's Blog

public class Demo {

    private int order = 0;

    public int getOrder() {
        return order;
    }

    public void setOrder(int order) {
        this.order = order;
    }
}

This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible.
For example, it is not generally permissible for one thread to modify a Collection while another thread is iterating over it. In general, the results of the iteration are undefined under these circumstances. Some Iterator implementations (including those of all the general purpose collection implementations provided by the JRE) may choose to throw this exception if this behavior is detected. Iterators that do this are known as fail-fast iterators, as they fail quickly and cleanly, rather that risking arbitrary, non-deterministic behavior at an undetermined time in the future.

public void sort(Comparator<? super E> c) {
        final int expectedModCount = modCount;
        Arrays.sort((E[]) elementData, 0, size, c);
        if (modCount != expectedModCount)
            throw new ConcurrentModificationException();
        modCount++;
    }

package com.nicksxs.mcp_demo;

import com.jayway.jsonpath.JsonPath;
import org.springframework.ai.tool.annotation.Tool;
import org.springframework.ai.tool.annotation.ToolParam;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestClient;

import java.util.List;
import java.util.Map;

@Service
public class WeatherService {

    private final RestClient restClient;

    public WeatherService() {
        this.restClient = RestClient.builder()
                .baseUrl("https://api.weather.gov")
                .defaultHeader("Accept", "application/geo+json")
                .defaultHeader("User-Agent", "WeatherApiClient/1.0 (your@email.com)")
                .build();
    }

    @Tool(description = "Get weather forecast for a specific latitude/longitude")
    public String getWeatherForecastByLocation(
            double latitude,   // Latitude coordinate
            double longitude   // Longitude coordinate
    ) {
        // 首先获取点位信息
        String pointsResponse = restClient.get()
                .uri("/points/{lat},{lon}", latitude, longitude)
                .retrieve()
                .body(String.class);

        // 从点位响应中提取预报URL
        String forecastUrl = JsonPath.read(pointsResponse, "$.properties.forecast");

        // 获取天气预报
        String forecast = restClient.get()
                .uri(forecastUrl)
                .retrieve()
                .body(String.class);

        // 从预报中提取第一个周期的详细信息
        String detailedForecast = JsonPath.read(forecast, "$.properties.periods[0].detailedForecast");
        String temperature = JsonPath.read(forecast, "$.properties.periods[0].temperature").toString();
        String temperatureUnit = JsonPath.read(forecast, "$.properties.periods[0].temperatureUnit");
        String windSpeed = JsonPath.read(forecast, "$.properties.periods[0].windSpeed");
        String windDirection = JsonPath.read(forecast, "$.properties.periods[0].windDirection");

        // 构建返回信息
        return String.format("Temperature: %s°%s\nWind: %s %s\nForecast: %s",
                temperature, temperatureUnit, windSpeed, windDirection, detailedForecast);
        // Returns detailed forecast including:
        // - Temperature and unit
        // - Wind speed and direction
        // - Detailed forecast description
    }

    @Tool(description = "Get weather alerts for a US state")
    public String getAlerts(@ToolParam(description = "Two-letter US state code (e.g. CA, NY)") String state) {
                
        // 获取指定州的天气警报
        String alertsResponse = restClient.get()
                .uri("/alerts/active/area/{state}", state)
                .retrieve()
                .body(String.class);

        // 检查是否有警报
        List<Map<String, Object>> features = JsonPath.read(alertsResponse, "$.features");
        if (features.isEmpty()) {
            return "当前没有活动警报。";
        }

        // 构建警报信息
        StringBuilder alertInfo = new StringBuilder();
        for (Map<String, Object> feature : features) {
            String event = JsonPath.read(feature, "$.properties.event");
            String area = JsonPath.read(feature, "$.properties.areaDesc");
            String severity = JsonPath.read(feature, "$.properties.severity"); 
            String description = JsonPath.read(feature, "$.properties.description");
            String instruction = JsonPath.read(feature, "$.properties.instruction");

            alertInfo.append("警报类型: ").append(event).append("\n");
            alertInfo.append("影响区域: ").append(area).append("\n");
            alertInfo.append("严重程度: ").append(severity).append("\n");
            alertInfo.append("描述: ").append(description).append("\n");
            if (instruction != null) {
                alertInfo.append("安全指示: ").append(instruction).append("\n");
            }
            alertInfo.append("\n---\n\n");
        }

        return alertInfo.toString();
    }

    // ......
}

public static void main(String[] args) {
        var stdioParams = ServerParameters.builder("java")
                .args("-jar", "/Users/shixuesen/Downloads/mcp-demo/target/mcp-demo-0.0.1-SNAPSHOT.jar")
                .build();

        var stdioTransport = new StdioClientTransport(stdioParams);

        var mcpClient = McpClient.sync(stdioTransport).build();

        mcpClient.initialize();

//        McpSchema.ListToolsResult toolsList = mcpClient.listTools();

        McpSchema.CallToolResult weather = mcpClient.callTool(
                new McpSchema.CallToolRequest("getWeatherForecastByLocation",
                        Map.of("latitude", "47.6062", "longitude", "-122.3321")));
        System.out.println(weather.content());

        McpSchema.CallToolResult alert = mcpClient.callTool(
                new McpSchema.CallToolRequest("getAlerts", Map.of("state", "NY")));

        mcpClient.closeGracefully();
    }