本文整理了Java中io.helidon.config.Config.ifExists()方法的一些代码示例，展示了Config.ifExists()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Config.ifExists()方法的具体详情如下：
包路径：io.helidon.config.Config
类名称：Config
方法名：ifExists

Config.ifExists介绍

[英]Performs the given action with the config node if node #exists(), otherwise does nothing.
[中]如果节点#exists（），则使用配置节点执行给定操作，否则不执行任何操作。

代码示例

代码示例来源：origin: oracle/helidon

/**
 * Initialize builder from specified configuration properties.
 * <p>
 * Supported configuration {@code properties}:
 * <ul>
 * <li>{@code optional} - type {@code boolean}, see {@link #optional()}</li>
 * <li>{@code polling-strategy} - see {@link PollingStrategy} for details about configuration format,
 * see {@link #pollingStrategy(Supplier)} or {@link #pollingStrategy(Function)}</li>
 * </ul>
 *
 * @param metaConfig configuration properties used to initialize a builder instance.
 * @return modified builder instance
 */
protected B init(Config metaConfig) {
  //optional / mandatory
  metaConfig.get(OPTIONAL_KEY)
      .asBoolean()
      .filter(value -> value) //filter `true` only
      .ifPresent(value -> optional());
  //polling-strategy
  metaConfig.get(POLLING_STRATEGY_KEY)
      .ifExists(cfg -> pollingStrategy(PollingStrategyConfigMapper.instance().apply(cfg, targetType)));
  //retry-policy
  metaConfig.get(RETRY_POLICY_KEY)
      .as(RetryPolicy::create)
      .ifPresent(this::retryPolicy);
  return thisBuilder;
}

代码示例来源：origin: oracle/helidon

/**
 * Load this builder from a configuration.
 *
 * @param config configuration to load from
 * @return updated builder instance
 */
public Builder config(Config config) {
  config.get("optional").as(Boolean.class).ifPresent(this::optional);
  config.get("authenticate").as(Boolean.class).ifPresent(this::authenticate);
  config.get("propagate").as(Boolean.class).ifPresent(this::propagate);
  config.get("allow-impersonation").asBoolean().ifPresent(this::allowImpersonation);
  config.get("principal-type").as(SubjectType.class).ifPresent(this::subjectType);
  config.get("atn-token.handler").as(TokenHandler.class).ifPresent(this::atnTokenHandler);
  config.get("atn-token").ifExists(this::verifyKeys);
  config.get("atn-token.jwt-audience").asString().ifPresent(this::expectedAudience);
  config.get("sign-token").ifExists(outbound -> outboundConfig(OutboundConfig.create(outbound)));
  config.get("sign-token").ifExists(this::outbound);
  return this;
}

代码示例来源：origin: oracle/helidon

/**
 * Load this builder from a configuration.
 *
 * @param config configuration to load from
 * @return updated builder instance
 */
public Builder config(Config config) {
  config.get("optional").asBoolean().ifPresent(this::optional);
  config.get("authenticate").asBoolean().ifPresent(this::authenticate);
  config.get("propagate").asBoolean().ifPresent(this::propagate);
  config.get("allow-impersonation").asBoolean().ifPresent(this::allowImpersonation);
  config.get("principal-type").asString().as(SubjectType::valueOf).ifPresent(this::subjectType);
  config.get("atn-token.handler").as(TokenHandler::create).ifPresent(this::atnTokenHandler);
  config.get("atn-token").ifExists(this::verifyKeys);
  config.get("atn-token.jwt-audience").asString().ifPresent(this::expectedAudience);
  config.get("atn-token.default-key-id").asString().ifPresent(this::defaultKeyId);
  config.get("atn-token.verify-key").asString().ifPresent(this::publicKeyPath);
  config.get("sign-token").ifExists(outbound -> outboundConfig(OutboundConfig.create(outbound)));
  config.get("sign-token").ifExists(this::outbound);
  org.eclipse.microprofile.config.Config mpConfig = ConfigProviderResolver.instance().getConfig();
  mpConfig.getOptionalValue(CONFIG_PUBLIC_KEY, String.class).ifPresent(this::publicKey);
  mpConfig.getOptionalValue(CONFIG_PUBLIC_KEY_PATH, String.class).ifPresent(this::publicKeyPath);
  mpConfig.getOptionalValue(CONFIG_EXPECTED_ISSUER, String.class).ifPresent(this::expectedIssuer);
  return this;
}

代码示例来源：origin: oracle/helidon

});
serverConfig.get("static.classpath").ifExists(cpConfig -> {
  Config context = cpConfig.get("context");
serverConfig.get("static.path").ifExists(pathConfig -> {
  Config context = pathConfig.get("context");
  StaticContentSupport.Builder pBuilder = StaticContentSupport.builder(pathConfig.get("location").as(Path.class).get());

代码示例来源：origin: io.helidon.config/helidon-config

/**
 * Initialize builder from specified configuration properties.
 * <p>
 * Supported configuration {@code properties}:
 * <ul>
 * <li>{@code optional} - type {@code boolean}, see {@link #optional()}</li>
 * <li>{@code polling-strategy} - see {@link PollingStrategy} for details about configuration format,
 * see {@link #pollingStrategy(Supplier)} or {@link #pollingStrategy(Function)}</li>
 * </ul>
 *
 * @param metaConfig configuration properties used to initialize a builder instance.
 * @return modified builder instance
 */
protected B init(Config metaConfig) {
  //optional / mandatory
  metaConfig.get(OPTIONAL_KEY)
      .asBoolean()
      .filter(value -> value) //filter `true` only
      .ifPresent(value -> optional());
  //polling-strategy
  metaConfig.get(POLLING_STRATEGY_KEY)
      .ifExists(cfg -> pollingStrategy(PollingStrategyConfigMapper.instance().apply(cfg, targetType)));
  //retry-policy
  metaConfig.get(RETRY_POLICY_KEY)
      .as(RetryPolicy::create)
      .ifPresent(this::retryPolicy);
  return thisBuilder;
}

代码示例来源：origin: io.helidon.security.providers/helidon-security-providers-jwt

/**
 * Load this builder from a configuration.
 *
 * @param config configuration to load from
 * @return updated builder instance
 */
public Builder config(Config config) {
  config.get("optional").as(Boolean.class).ifPresent(this::optional);
  config.get("authenticate").as(Boolean.class).ifPresent(this::authenticate);
  config.get("propagate").as(Boolean.class).ifPresent(this::propagate);
  config.get("allow-impersonation").asBoolean().ifPresent(this::allowImpersonation);
  config.get("principal-type").as(SubjectType.class).ifPresent(this::subjectType);
  config.get("atn-token.handler").as(TokenHandler.class).ifPresent(this::atnTokenHandler);
  config.get("atn-token").ifExists(this::verifyKeys);
  config.get("atn-token.jwt-audience").asString().ifPresent(this::expectedAudience);
  config.get("sign-token").ifExists(outbound -> outboundConfig(OutboundConfig.create(outbound)));
  config.get("sign-token").ifExists(this::outbound);
  return this;
}

代码示例来源：origin: io.helidon.microprofile.jwt/helidon-microprofile-jwt-auth

/**
 * Load this builder from a configuration.
 *
 * @param config configuration to load from
 * @return updated builder instance
 */
public Builder config(Config config) {
  config.get("optional").asBoolean().ifPresent(this::optional);
  config.get("authenticate").asBoolean().ifPresent(this::authenticate);
  config.get("propagate").asBoolean().ifPresent(this::propagate);
  config.get("allow-impersonation").asBoolean().ifPresent(this::allowImpersonation);
  config.get("principal-type").asString().as(SubjectType::valueOf).ifPresent(this::subjectType);
  config.get("atn-token.handler").as(TokenHandler::create).ifPresent(this::atnTokenHandler);
  config.get("atn-token").ifExists(this::verifyKeys);
  config.get("atn-token.jwt-audience").asString().ifPresent(this::expectedAudience);
  config.get("atn-token.default-key-id").asString().ifPresent(this::defaultKeyId);
  config.get("atn-token.verify-key").asString().ifPresent(this::publicKeyPath);
  config.get("sign-token").ifExists(outbound -> outboundConfig(OutboundConfig.create(outbound)));
  config.get("sign-token").ifExists(this::outbound);
  org.eclipse.microprofile.config.Config mpConfig = ConfigProviderResolver.instance().getConfig();
  mpConfig.getOptionalValue(CONFIG_PUBLIC_KEY, String.class).ifPresent(this::publicKey);
  mpConfig.getOptionalValue(CONFIG_PUBLIC_KEY_PATH, String.class).ifPresent(this::publicKeyPath);
  mpConfig.getOptionalValue(CONFIG_EXPECTED_ISSUER, String.class).ifPresent(this::expectedIssuer);
  return this;
}

代码示例来源：origin: io.helidon.microprofile.server/helidon-microprofile-server

});
serverConfig.get("static.classpath").ifExists(cpConfig -> {
  Config context = cpConfig.get("context");
serverConfig.get("static.path").ifExists(pathConfig -> {
  Config context = pathConfig.get("context");
  StaticContentSupport.Builder pBuilder = StaticContentSupport.builder(pathConfig.get("location").as(Path.class).get());