algebraically closed field https://en.wikipedia.org/wiki/Algebraically_closed_field As an example, the field of real numbers is not algebraically closed, because the polynomial equation x2 + 1 = 0  has no solution in real numbers, even though all it…

https://math.berkeley.edu/~myzhang/qual.html?tdsourcetag=s_pcqq_aiomsg <!-- Page Content --> <div class="container"> <div class="row" style="margin-top: 80px; margin-bottom: 40px;"> <h3 style="text-a…

起因:在函数中新建scanner对象,然后多次调用此方法出现上述异常 原因:Scanner(system.in)在Scanner中接受的是键盘 输入,当调用close()方法时 Scanner的关闭会导致System.in的关闭,System.in是标准输入(键盘输入),只能关一次,关闭后不能再打开. 解决办法1:在主函数的声明,然后作为参数传入方法中 解决办法2: 查看scanner源码 // Boolean indicating if this scanner has been closed…

TCP, relative to the SOCKET developers create process and link remove process consists of the TCP/IP protocol stack is automatically created. So the developer doesn't need to control this process. But to understand TCP the underlying mechanism is qui…

part of Hypertext Transfer Protocol -- HTTP/1.1RFC 2616 Fielding, et al. 14 Header Field Definitions(规定) This section(部分,章节) defines(规定定义) the syntax(语法) and semantics(语意) of all standard(标准) HTTP/1.1 header fields. For entity-header fields, both sen…

环境:java JDK 1.8.org.apache.commons-net-3.6.jar.端口已放开 FTPClient ftpClient = new FTPClient(protocol, false); ftpClient.setRemoteVerificationEnable(false); ftpClient.setControlKeepAliveTimeout(300); ftpClient.setDataTimeout(300); InputStream fin = null;…

Come from :https://neilparkhurst.com/2016/08/20/field-service-work-order-theory/ In this post I aim to continue my series covering all aspects of Field Service for Microsoft Dynamics CRM, work orders are the primary entity within Field Service. Think…

       首先说明一下,hibernate的延迟加载特性(lazy).所谓的延迟加载就是当真正需要查询数据时才执行数据加载操作.因为hibernate当中支持实体对象,外键会与实体对象关联起来.如果没有这一特性,当查询某一个含有外键的实体对象时,hibernate会把其他实体对象的数据都查询出来.简单的来说,当你想查询某个对象时,实际上调用了多条查询语句.有了延迟加载特性,就避免了这种情况的发生,当你真正的使用get另外一个实体对象时,才再执行下面一条查询语句.           但有些时…

本篇引用以下三个链接: http://www.tgerm.com/2012/01/recordtype-specific-picklist-values.html?m=1 https://github.com/abhinavguptas/Multi-RecordType-Sobject-Picklist-Describer http://bobbuzzard.blogspot.com/2012/01/record-type-picklist-values.html 我们知道,record typ…

Android 程序开发完成后,如果要发布到互联网上供别人使用,就需要将自己的程序打包成Android 安装包文件(Android Package,APK),其扩展名为.apk.使用run as 也能生成一个APK安装包,但是使用run as 生成的是测试的安装包,只供开发者自己测试使用. 接下来就以HelloWord程序为例演示如何生成正式的APK文件. 1.右键项目名称,依次选择Android Tools——>Explort Signed Application Package,如图所示:…