JavaEEServlet的异步处理 JavaEEServlet 异步处理
Servlet3.0对异步处理提供了支持。阻塞的Servlet每个请求到达Web应用后，Web应用会为其分配一个线程来专门负责该请求，直到响应发送前，该线程都不会被线程池回收。若有些请求需要长时间处理（比如某些耗时运算或者需要等待某个资源），就会阻塞线程，若这类的请求很多，许多线程都将被长时间占用，对于系统就会产生较大负担，甚至会造成程序的效能瓶颈。...
View Article常见DML语句汇总 DML语句
DML操作是指对数据中表记录的操作，主要包括表记录的插入(insert)、更新(update)、删除(delete)和查询(select)，是开发人员日常使用最频繁的操作，下面依次对它们进行介绍。 (1) 插入记录 INSERT INTO tablename(field1,field2,…,fieldn) VALUES(value1,vaule2,…,valuen) (2) 更新记录UPDATE...
View ArticleHibernate5之MappingException解惑 Hibernate5 MappingException
今天捣鼓了一个 hibernate 程序，用的是 hibernate 5 版本，发现在创建 ServiceRegistryBuilder 对象时找不到这个类，于是直接去 hibernate-core-5.2.6.Final.jar 里面确认一下，还真的没有，而在网上看的一篇帖子说可以用 StandardServiceRegistryBuilder...
View ArticleMaven本地安装ojdbc Maven 安装ojdbc
我们在使用Java来操作Oracle数据库的时候需要用到Oracle的JDBC驱动。我们通常使用Maven来管理所需要的依赖，由于Maven中心仓库没有Oracle JDBC驱动下载，所以我们要自己打包安装。...
View Articlewamp环境下出现You don’t have permission to access/on this server提示 wamp环境
****本地搭建wamp，输入http://127.0.0.1访问正常，当输入http://localhost/，apache出现You don’t have permission to access/on this server.的提示，如何解决?**** 找到httpd.conf，用记事本打开httpd.conf，然后将Options FollowSymLinks AllowOverride...
View ArticleRedis安装及使用 Redis安装
redis介绍redis是一种key-value型数据结构储存系统，可以用作数据库、缓存和消息中间件。 它支持多种类型的数据结构，如 字符串（strings）， 散列（hashes）， 列表（lists）， 集合（sets）， 有序集合（sorted sets） 与范围查询， bitmaps， hyperloglogs 和 地理空间（geospatial） 索引半径查询。 Redis 内置了...
View ArticleSpark on Yarn提交任务时报ClosedChannelException解决方案
spark2.1出来了，想玩玩就搭了个原生的apache集群，但在standalone模式下没有任何问题，基于apacheHadoop 2.7.3使用spark on yarn一直报这个错。 报错日志如下： Warning: Master yarn-client is deprecated since 2.0. Please use master "yarn" with specified...
View ArticleOrientDB 2.2.16 发布，文档数据库
OrientDB 2.2.16 发布了，Orient DB 是一个可伸缩的文档数据库，支持 ACID 事务处理。 更新内容： Studio A new OrientDB logo that includes the text "Community" or "Enterprise" is now shown according to the OrientDB Edition in use -...
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Giphy Engineering with Anthony Johnson
Giphy is a search engine for gifs, the short animated graphics that we see around the Internet. Giphy is also a creative platform where people create new gifs. Every search engine requires the...
View ArticleCloudera Enterprise 5.10 is Now Available
Cloudera is proud to announce that Cloudera Enterprise 5.10 is now generally available (GA). The highlights of this release include the GA of the new columnar storage engine Apache Kudu, improved cloud...
View ArticleUpdating Documents in DocumentDb
In my last few posts, I’ve been working on an Azure Mobile Apps replacement service. It will run in Azure Functions and use DocumentDb as a backing store. Neither of these requirements are possible in...
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MongoDB生态 社区开源工具篇
工欲善其事，必先利其器，我们在使用数据库时，通常需要各种工具的支持来提高效率；很多新用户在刚接触 MongoDB 时，遇到的问题是『不知道有哪些现成的工具可以使用』，本系列文章将主要介绍 MongoDB 生态在工具、driver、可视化管理等方面的支持情况。 MongoDB 生态 可视化管理工具 MongoDB 生态 客户端 Driver 支持 MongoDB 生态 官方命令行工具...
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The 5-Minute Interview: Cindee Madison, Data Engineer at Gallium Artistic...
ByRachel Howard, Community Editor | February 3, 2017 “Using artificial intelligence, we’re creating what you could call a social network of the mind,” says Cindee Madison , Data Engineer at Gallium...
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Redis Caching in the Google Cloud Platform
Caching is one of those solutions that is often added after you realize that there is a performance problem with your system. For example, fetching records from a database may be fast when you are...
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Moving from SQL Server to Couchbase Part 1: Data Modeling
In this series of blog posts, I’m going to lay out the considerations when moving to a document database when you have a relational background. Specifically, Microsoft SQL Server as compared...
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What’s New in Cloudera Director 2.3?
Cloudera Director helps you deploy, scale, and manage Apache Hadoop clusters in the cloud of your choice. Its enterprise-grade features deliver a reliable mechanism for establishing production-ready...
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Couchbase and the Document-Oriented NoSQL Database
As a developer advocate atCouchbase, I often travel around and meet people who either have no idea what NoSQL is, or more importantly what Couchbase is. For the people who are already familiar with...
View ArticleMiles to go ... - Arun Gupta: Microservice using Docker stack deploy WildFly,...
There is plenty of material onmicroservices, just google it ! I gave a presentation onrefactoring monolith to microservices at Devoxx Belgium a couple of years back and it hasgood reviews: This blog...
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ArangoDB 3.1.10 发布，高性能 NoSQL 数据库
ArangoDB 3.1.10 发布了，Arangodb 是一个开源数据库，具有用于文档，图形和键值的灵活数据模型。同时也是一个高性能数据库，使用类似 SQL 的查询语言或 javascript 扩展构建高性能应用。 更新内容： 1、更新 joi：8.4.2 to 9.2.0 joi-to-json-schema： 2.2.0 to 2.3.0 sinon：1.17.4 to 1.17.6...
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Dynamically Loading Markers with MongoDB in Ionic 2 Part 2
InPart 1 of this tutorial series, we built a Node & Express server which uses MongoDB to store location data. We created a route that we could make a POST request to, and through supplying some...
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