如何从Bluemix中的OpenWhisk Java操作访问VCAP_SERVICES？

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

// 获取VCAP_SERVICES环境变量的值
String vcapServices = System.getenv("VCAP_SERVICES");

// 解析VCAP_SERVICES字符串
ObjectMapper objectMapper = new ObjectMapper();
JsonNode vcapServicesJson = objectMapper.readTree(vcapServices);

// 获取数据库服务实例的详细信息
JsonNode databaseService = vcapServicesJson.get("database-service").get(0);
String databaseHost = databaseService.get("credentials").get("host").asText();
int databasePort = databaseService.get("credentials").get("port").asInt();
String databaseUsername = databaseService.get("credentials").get("username").asText();
String databasePassword = databaseService.get("credentials").get("password").asText();

// 建立与数据库服务的连接
Connection connection = DriverManager.getConnection("jdbc:mysql://" + databaseHost + ":" + databasePort + "/dbname", databaseUsername, databasePassword);

// 执行数据库操作
// ...

// 关闭连接
connection.close();