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字段掩码

在 Google Ads API 中，更新是使用字段掩码完成的。字段掩码列出您打算随更新而更改的所有字段，以及任何指定的字段字段掩码范围外的其他字词，即使发送到服务器，也会被忽略。

FieldMaskUtil

推荐使用我们的内置字段掩码生成字段掩码实用程序，它可让您通过修改的对象（而不是从零开始构建它们

以下是一个更新广告系列的示例：

// Creates a Campaign object with the proper resource name and any other changes.
Campaign campaign =
    Campaign.newBuilder()
        .setResourceName(ResourceNames.campaign(customerId, campaignId))
        .setStatus(CampaignStatus.PAUSED)
        .build();

// Constructs an operation that will update the campaign, using the FieldMasks'
// allSetFieldsOf utility to derive the update mask. This mask tells the Google
// Ads API which attributes of the campaign you want to change.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaign)
        .setUpdateMask(FieldMasks.allSetFieldsOf(campaign))
        .build();

// Sends the operation in a mutate request.
MutateCampaignsResponse response =
    campaignServiceClient.mutateCampaigns(
        customerId.toString(), Collections.singletonList(operation));

此示例首先创建一个空的 Campaign 对象，然后设置其资源以便 API 了解正在更新哪个广告系列。

该示例对广告系列使用 FieldMasks.allSetFieldsOf() 方法自动生成枚举所有已设置字段的字段掩码。然后，您可以将返回的掩码直接传递给 update 调用。

如果您需要使用现有对象更新一些字段，可以按如下所示修改代码：

Campaign existingCampaign;

// Obtains existingCampaign from elsewhere.
...

// Creates a new campaign based off the existing campaign and updates the
// campaign by setting its status to paused.
Campaign campaignToUpdate =
    existingCampaign.toBuilder()
        .setStatus(CampaignStatus.PAUSED)
        .build();

// Constructs an operation that will update the campaign, using the FieldMasks'
// compare utility to derive the update mask. This mask tells the Google Ads API
// which attributes of the campaign you want to change.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaignToUpdate)
        .setUpdateMask(FieldMasks.compare(existingCampaign, campaignToUpdate))
        .build();

// Sends the operation in a mutate request.
MutateCampaignsResponse response =
    campaignServiceClient.mutateCampaigns(
        customerId.toString(), Collections.singletonList(operation));

要从头开始创建字段掩码，您首先需要创建一个 FieldMask 对象，然后将要更改的每个字段的名称添加到对象。

FieldMask fieldMask =
    FieldMask.newBuilder()
        .addPaths("status")
        .addPaths("name")
        .build();

更新消息字段及其子字段

MESSAGE 字段可以包含子字段（例如 MaximizeConversions，其中包含三个： target_cpa_micros, cpc_bid_ceiling_micros 和 cpc_bid_floor_micros），也可以不将任何（例如 ManualCpm）。

没有已定义子字段的消息字段

在更新未使用任何子字段定义的 MESSAGE 字段时，请使用 FieldMaskUtil ，以生成字段掩码（如上所述）。

包含已定义子字段的消息字段

更新使用不包含子字段的子字段定义的 MESSAGE 字段时因此您必须手动设置将每个可变的 MESSAGE 子字段添加到 FieldMask，类似于上面的示例，它从头开始创建字段掩码。

一个常见的例子是，在未设置任何选项的情况下更新广告系列的出价策略新出价策略的字段。以下示例演示了如何更新广告系列以使用 MaximizeConversions出价策略而不必为出价策略设置任何子字段。

在本例中，使用 allSetFieldsOf() 和 compare() 方法的 FieldMaskUtil 未达到预期目标。

以下示例将生成包含以下内容的字段掩码： maximize_conversions。但是，Google Ads API 不允许这种行为防止意外清除字段 FieldMaskError.FIELD_HAS_SUBFIELDS 错误。

// Creates a campaign with the proper resource name and an empty
// MaximizeConversions field.
Campaign campaign = Campaign.newBuilder()
    .setResourceName(ResourceNames.campaign(customerId, campaignId))
    .setMaximizeConversions(MaximizeConversions.newBuilder().build())
    .build();

// Constructs an operation, using the FieldMasks' allSetFieldsOf utility to
// derive the update mask. The field mask will include 'maximize_conversions`,
// which will produce a FieldMaskError.FIELD_HAS_SUBFIELDS error.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaign)
        .setUpdateMask(FieldMasks.allSetFieldsOf(campaign))
        .build();

// Sends the operation in a mutate request that will result in a
// FieldMaskError.FIELD_HAS_SUBFIELDS error because empty MESSAGE fields cannot
// be included in a field mask.
MutateCampaignsResponse response =
    campaignServiceClient.mutateCampaigns(
        customerId.toString(), Collections.singletonList(operation));

以下示例演示了如何正确更新广告系列以使用 MaximizeConversions出价策略，但未设置任何子字段。

// Creates a Campaign object with the proper resource name.
Campaign campaign = Campaign.newBuilder()
    .setResourceName(ResourceNames.campaign(customerId, campaignId))
    .build();

// Creates a field mask from the existing campaign and adds all of the mutable
// fields (only one in this case) on the MaximizeConversions bidding strategy to
// the field mask. Because this field is included in the field mask but
// excluded from the campaign object, the Google Ads API will set the campaign's
// bidding strategy to a MaximizeConversions object without any of its subfields
// set.
FieldMask fieldMask = FieldMasks.allSetFieldsOf(campaign)
    .toBuilder()
    // Only include 'maximize_conversions.target_cpa_micros' in the field mask
    // as it is the only mutable subfield on MaximizeConversions when used as a
    // standard bidding strategy.
    //
    // Learn more about standard and portfolio bidding strategies here:
    // https://developers.google.com/google-ads/api/docs/campaigns/bidding/assign-strategies
    .addPaths("maximize_conversions.target_cpa_micros")
    .build();

// Creates an operation to update the campaign with the specified fields.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaign)
        .setUpdateMask(fieldMask)
        .build();

清除字段

某些字段是可以明确清除的。与上面的示例类似，您必须明确地将这些字段添加到字段掩码中。例如，假设您有一个广告系列，该广告系列采用的是MaximizeConversions出价策略，并且 “target_cpa_micros”字段的值大于 0。

系统会运行以下代码：不过，maximize_conversions.target_cpa_micros 因此也不会对 target_cpa_micros 字段：

// Creates a campaign with the proper resource name and a MaximizeConversions
// object with target_cpa_micros set to 0.
Campaign campaign =
    Campaign.newBuilder()
        .setResourceName(ResourceNames.campaign(customerId, campaignId))
        .setMaximizeConversions(
            MaximizeConversions.newBuilder().setTargetCpa(0).build())
        .setStatus(CampaignStatus.PAUSED)
        .build();

// Constructs an operation, using the FieldMasks' allSetFieldsOf utility to
// derive the update mask. However, the field mask will NOT include
// 'maximize_conversions.target_cpa_micros'.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaign)
        .setUpdateMask(FieldMasks.allSetFieldsOf(campaign))
        .build();

// Sends the operation in a mutate request that will succeed but will NOT update
// the 'target_cpa_micros' field because
// 'maximize_conversions.target_cpa_micros' was not included in the field mask.
MutateCampaignsResponse response =
    campaignServiceClient.mutateCampaigns(
        customerId.toString(), Collections.singletonList(operation));

下一个示例演示了如何正确清除 target_cpa_micros 字段（MaximizeConversions 出价策略）。

// Creates a Campaign object with the proper resource name.
Campaign campaign = Campaign.newBuilder()
    .setResourceName(ResourceNames.campaign(customerId, campaignId))
    .build();

// Constructs a field mask from the existing campaign and adds the
// 'maximize_conversions.target_cpa_micros' field to the field mask, which will
// clear this field from the bidding strategy without impacting any other fields
// on the bidding strategy.
FieldMask fieldMask = FieldMasks.allSetFieldsOf(campaign)
    .toBuilder()
    .addPaths("maximize_conversions.target_cpa_micros")
    .build();

// Creates an operation to update the campaign with the specified field.
CampaignOperation operation =
    CampaignOperation.newBuilder()
        .setUpdate(campaign)
        .setUpdateMask(fieldMask))
        .build();

请注意，上面的示例确实适用于在 Google Ads API 中定义为 optional protocol buffers。但自从使用 target_cpa_micros 不是 optional 字段，则“不正确”示例不会更新清除 target_cpa 字段。