Java 8 已达到支持终止期限，并将于 2026 年 1 月 31 日
弃用。弃用后，您将无法部署 Java 8 应用，即使您的组织之前曾使用组织政策重新启用旧版运行时的部署，也无法部署。现有的 Java 8 应用在
弃用日期之后将继续运行并接收流量。我们建议您
迁移到最新支持的 Java 版本。
App Engine MapReduce
使用集合让一切井井有条
根据您的偏好保存内容并对其进行分类。
重要提示：Google 已将 Java 和 Python MapReduce 库的支持和进一步开发转移到开源社区。GitHub 上提供了源代码和文档。
MapReduce 是一种以并行分布式方式处理大量数据的编程模型。该模型适用于长时间运行且无法在单个请求范围内处理的大型作业，例如以下任务：
- 分析应用日志
- 汇总来自外部来源的相关数据
- 将数据从一种格式转换为另一种格式
- 导出数据以供外部分析
App Engine MapReduce 是一个由社区维护的开放源代码库，基于 App Engine 服务（包括 Datastore 和任务队列）构建而成。您可以在 GitHub 上的以下位置找到该库：
何处找到文档
点击上述 GitHub 项目的 Wiki 图标即可获得 Mapreduce 文档。但为方便起见，您还可以通过以下链接访问 Java 和 Python MapReduce 的文档：
如未另行说明，那么本页面中的内容已根据知识共享署名 4.0 许可获得了许可，并且代码示例已根据 Apache 2.0 许可获得了许可。有关详情，请参阅 Google 开发者网站政策。Java 是 Oracle 和/或其关联公司的注册商标。
最后更新时间 (UTC)：2025-09-04。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-09-04。"],[[["\u003cp\u003eGoogle has transitioned the Java and Python MapReduce libraries to open-source, with the source code and documentation now available on GitHub.\u003c/p\u003e\n"],["\u003cp\u003eMapReduce is a programming model designed for processing large datasets in parallel, making it useful for long-running jobs like log analysis and data transformation.\u003c/p\u003e\n"],["\u003cp\u003eApp Engine MapReduce is a community-maintained, open-source library built on App Engine services like Datastore and Task Queues.\u003c/p\u003e\n"],["\u003cp\u003eThe MapReduce library's documentation for both Java and Python is accessible via the GitHub wiki, at the link provided for your convenience.\u003c/p\u003e\n"]]],[],null,["# MapReduce for App Engine\n\n**Important:**\nGoogle has transitioned support and further development of the\nJava and Python MapReduce libraries to\nthe open source community.\nThe source code and documentation are\navailable on [GitHub](https://github.com/GoogleCloudPlatform/appengine-mapreduce/wiki)\n\nMapReduce is a programming model for processing large amounts of data in a\nparallel and distributed fashion. It is useful for large, long-running jobs\nthat cannot be handled within the scope of a single request, tasks like:\n\n- Analyzing application logs\n- Aggregating related data from external sources\n- Transforming data from one format to another\n- Exporting data for external analysis\n\nApp Engine MapReduce is a community-maintained, open source library that is\nbuilt on top of App Engine services, including Datastore and Task Queues.\nThe library is available on GitHub at these locations:\n\n- [Java](https://github.com/GoogleCloudPlatform/appengine-mapreduce/tree/master/java) source project.\n\n- [Python](https://github.com/GoogleCloudPlatform/appengine-mapreduce/tree/master/python) source project.\n\nWhere to find documentation\n---------------------------\n\nThe documentation for Mapreduce is available by clicking the wiki icon for the GitHub projects\nlinked above. However, for your convenience, you can also access the\ndocumentation for both Java and Python MapReduce at the following link:\n\n- [Java and Python MapReduce Documentation](https://github.com/GoogleCloudPlatform/appengine-mapreduce/wiki)"]]
