Integration of Java functions with caching services in serverless architecture

import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import com.google.cloud.storage.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import java.io.BufferedWriter;
import java.io.IOException;

public class CacheIntegration implements HttpFunction {
  private static final Storage STORAGE = StorageOptions.getDefaultInstance().getService();

  @Override
  public void service(HttpRequest request, HttpResponse response) throws IOException {
    String key = request.getFirstQueryParameter("key").orElse("");
    String value = getCachedValue(key);

    // 如果缓存中没有值，则从数据库中获取
    if (value == null) {
      value = getFromDatabase(key);
      // 将值插入缓存
      setCachedValue(key, value);
    }

    BufferedWriter writer = response.getWriter();
    writer.write(value);
  }

  // 从数据库中获取值
  private String getFromDatabase(String key) {
    // 实际实现会从数据库中检索值
    return "Value from database";
  }

  // 获取缓存中的值
  private String getCachedValue(String key) {
    BlobId blobId = BlobId.of("cache-bucket", key);
    Blob blob = STORAGE.get(blobId);
    return blob != null ? blob.getContentType().toString() : null;
  }

  // 将值插入缓存
  private void setCachedValue(String key, String value) {
    BlobId blobId = BlobId.of("cache-bucket", key);
    BlobInfo blobInfo = BlobInfo.newBuilder(blobId).setContentType(value).build();
    STORAGE.create(blobInfo, value.getBytes());
  }
}