java

What are the alternatives to using an ORDER BY in a Subquery in the JPA Criteria API?

由 喜你入骨 提交于 2021-02-18 22:01:57
问题 Consider the following two tables: Project ( id, project_name) Status ( id, id_project, status_name) Where Status contains all statuses in which a Project has been. Lets say we want to query all projects for which the latest status has the name "new". The Sql query that I come up with is: SELECT q.id_project FROM status q WHERE q.status_name like 'new' AND q.id IN ( SELECT TOP 1 sq.id from status sq WHERE q.id_project = sq.id_project ORDER BY sq.id DESC ) I'm trying to replicate the above

Sending base64 encoded image to server using HttpUrlConnection Android

由 。_饼干妹妹 提交于 2021-02-18 22:01:51
问题 I'm trying to send base64 encoded images to a server using HttpUrlConnection. The problem I'm having is that most images gets sent successfully, however some generate a FileNotFound exception. My code for encoding the image can be found below. public static String encodeImage(Bitmap thumbnail) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); thumbnail.compress(Bitmap.CompressFormat.JPEG, 100, baos); byte[] b = baos.toByteArray(); String imageEncoded = Base64.encodeToString(b,Base64

Singleton classes

由 只谈情不闲聊 提交于 2021-02-18 22:01:47
问题 Is there any difference between a Singleton class and a class with all static members (i.e. methods and attributes). I could not find any instance where 'all static member class' would not achieve the same functionality as class properly implementing Singleton pattern? For eg. java.lang.Runtime is a proper Singleton class whereas java.lang.System has all static method for access and merely has a private constructor to avoid external construction . Does anybody know why classes like Runtime

Singleton classes

由 为君一笑 提交于 2021-02-18 22:01:36
问题 Is there any difference between a Singleton class and a class with all static members (i.e. methods and attributes). I could not find any instance where 'all static member class' would not achieve the same functionality as class properly implementing Singleton pattern? For eg. java.lang.Runtime is a proper Singleton class whereas java.lang.System has all static method for access and merely has a private constructor to avoid external construction . Does anybody know why classes like Runtime

Singleton classes

由 不问归期 提交于 2021-02-18 22:01:17
问题 Is there any difference between a Singleton class and a class with all static members (i.e. methods and attributes). I could not find any instance where 'all static member class' would not achieve the same functionality as class properly implementing Singleton pattern? For eg. java.lang.Runtime is a proper Singleton class whereas java.lang.System has all static method for access and merely has a private constructor to avoid external construction . Does anybody know why classes like Runtime

What are the alternatives to using an ORDER BY in a Subquery in the JPA Criteria API?

由 末鹿安然 提交于 2021-02-18 22:00:39
问题 Consider the following two tables: Project ( id, project_name) Status ( id, id_project, status_name) Where Status contains all statuses in which a Project has been. Lets say we want to query all projects for which the latest status has the name "new". The Sql query that I come up with is: SELECT q.id_project FROM status q WHERE q.status_name like 'new' AND q.id IN ( SELECT TOP 1 sq.id from status sq WHERE q.id_project = sq.id_project ORDER BY sq.id DESC ) I'm trying to replicate the above

Sending base64 encoded image to server using HttpUrlConnection Android

由 我的未来我决定 提交于 2021-02-18 21:59:58
问题 I'm trying to send base64 encoded images to a server using HttpUrlConnection. The problem I'm having is that most images gets sent successfully, however some generate a FileNotFound exception. My code for encoding the image can be found below. public static String encodeImage(Bitmap thumbnail) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); thumbnail.compress(Bitmap.CompressFormat.JPEG, 100, baos); byte[] b = baos.toByteArray(); String imageEncoded = Base64.encodeToString(b,Base64

Sending base64 encoded image to server using HttpUrlConnection Android

由 自古美人都是妖i 提交于 2021-02-18 21:58:30
问题 I'm trying to send base64 encoded images to a server using HttpUrlConnection. The problem I'm having is that most images gets sent successfully, however some generate a FileNotFound exception. My code for encoding the image can be found below. public static String encodeImage(Bitmap thumbnail) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); thumbnail.compress(Bitmap.CompressFormat.JPEG, 100, baos); byte[] b = baos.toByteArray(); String imageEncoded = Base64.encodeToString(b,Base64

idea中web.xml默认版本问题解决

由 纵然是瞬间 提交于 2021-02-18 21:43:42
问题描述：用idea的maven新建一个webapp项目，自动生成的web.xml默认版本是2.3版本（这版本连EL表达式都默认不能使用，无语了）。 Servlet 2.3： <? xml version="1.0" encoding="UTF-8" ?> <! DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" > < web-app > </ web-app > 1、临时解决办法： 把web.xml删掉。在Project Structure 里面的Modules重新添加一个Web.xml，能够生成并选择版本，但是这只是作用于当前项目。 2、永久解决办法： 修改默认版本，具体步骤如下： 进入“1.3”文件夹，找到jar包，如下图 用解压软件 打开文件,记住不是解压 。 按下图这个路径依次打开，找到web.xml文件： 直接打开web.xml，修改头文件，保存就可以了(注意：是在解压软件打开的的界面直接打开并修改web.xml，而不是解压成文件夹之后修改，也就是要保证jar包本来的结构不变)。 下面这个就是3.0的web.xml头文件，直接复制就可以。 <? xml version="1.0"

SpringBoot整合Zookeeper和Dubbo

由 北慕城南 提交于 2021-02-18 21:31:18
一、Dubbo 1、 Dubbo定义 Dubbo是Alibaba开源的分布式服务框架，它最大的特点是按照分层的方 式来架构，使用这种方式可以使各个层之间解耦合（或者最大限度地松耦 合）。从服务模型的角度来看，Dubbo采用的是一种非常简单的模型，要 么是提供方提供服务，要么是消费方消费服务，所以基于这一点可以抽象 出服务提供方（Provider）和服务消费方（Consumer）两个角色。 Dubbo就是资源调度和治理中心的管理工具。 2、Dubbo架构 节点角色说明： Provider: 暴露服务的服务提供方。 Consumer: 调用远程服务的服务消费方。 Registry: 服务注册与发现的注册中心。 Monitor: 统计服务的调用次调和调用时间的监控中心。 Container: 服务运行容器。 调用关系说明： 0. 服务容器负责启动，加载，运行服务提供者。 1. 服务提供者在启动时，向注册中心注册自己提供的服务。 2. 服务消费者在启动时，向注册中心订阅自己所需的服务。 3. 注册中心返回服务提供者地址列表给消费者，如果有变更，注册中心将基于长连接推送变更数据给消费者。 4. 服务消费者，从提供者地址列表中，基于软负载均衡算法，选一台提供者进行调用，如果调用失败，再选另一台调用。 5. 服务消费者和提供者，在内存中累计调用次数和调用时间，定时每分钟发送一次统计数据到监控中心
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