Java函数在物联网中的应用有哪些？

import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.logging.Logger;

public class TemperatureAlert implements HttpFunction {
  private static final Logger logger = Logger.getLogger(TemperatureAlert.class.getName());

  @Override
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    BufferedWriter writer = response.getWriter();
    // 从请求中解析温度值
    String temperature = request.getFirstQueryParameter("temperature").orElse("0");
    // 设置警报阈值
    int threshold = 30;

    // 检查温度是否超过阈值，并触发警报
    if (Integer.parseInt(temperature) > threshold) {
      logger.info("Temperature exceeded threshold: " + temperature);
      writer.write("ALERT: Temperature exceeded threshold!");
    } else {
      writer.write("Temperature is within normal range.");
    }
  }
}

import com.google.cloud.iot.v1.DeviceManagerClient;
import com.google.cloud.iot.v1.Device;
import com.google.cloud.iot.v1.DeviceCredential;
import com.google.cloud.iot.v1.DeviceCredential.PublicKeyCredential;
import com.google.cloud.iot.v1.DeviceName;
import com.google.cloud.iot.v1.Path;
import com.google.protobuf.ByteString;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class DeviceRegistration {
  public static void registerDevice() throws IOException {
    // Set the project and cloud region
    String projectId = "YOUR_PROJECT_ID";
    String cloudRegion = "YOUR_CLOUD_REGION";

    // Instantiate the client
    try (DeviceManagerClient client = DeviceManagerClient.create()) {

      // Set the device name
      String deviceId = "YOUR_DEVICE_ID";
      DeviceName deviceName = DeviceName.of(projectId, cloudRegion, deviceId);

      // Read the public key from file
      byte[] keyBytes = Files.readAllBytes(Paths.get("PATH_TO_PUBLIC_KEY"));
      ByteString key = ByteString.copyFrom(keyBytes);

      // Create the public key credential
      PublicKeyCredential publicKeyCredential =
          PublicKeyCredential.newBuilder()
              .setKey(key)
              .setFormat("RSA_X509_PEM")
              .build();

      // Create the device credential
      DeviceCredential credential =
          DeviceCredential.newBuilder().setPublicKey(publicKeyCredential).build();

      // Set the device metadata and credential
      Device device = Device.newBuilder().setId(deviceId).setCredentials(credential).build();

      // Create the device on a registry
      Device registeredDevice = client.createDevice(device, deviceName);

      // Print the device detail
      System.out.println("Registered device: " + registeredDevice.getName());
    }
  }
}

import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import com.google.gson.Gson;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.Map;

public class DashboardVisualization implements HttpFunction {

  private static final Gson gson = new Gson();

  @Override
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    BufferedWriter writer = response.getWriter();
    // 从请求中解析数据
    Map<String, String> data = gson.fromJson(request.getReader(), Map.class);

    // 可视化数据，例如生成图表或仪表板
    // ...可视化逻辑...

    // 将可视化结果写入响应
    writer.write("VISUALIZATION_RESULT");
  }
}