一.Enum的产生 Java1.5中引入了枚举的语法,包括Enum,EnumSet,EnumMap等.其中Enum就是我们在C或C++中见过的枚举类型,但是Java中的枚举又比C或C++中的枚举更成熟和复杂.在Java中,枚举算是一种特殊的类,也就是class,因此它可以做很多类相关的事情,而不仅仅是定义几个枚举值 二.Android官方建议 Android官网不建议使用enums,占用内存多(Enums often require more than twice as much memory
Android版本28使用http请求报错not permitted by network security policy android模拟器调试登录的时候报错 CLEARTEXT communication to to 52.76.xx.xxx not permitted by network security policy 2018-10-17 20:42:09.532 18048-18048/com.aax.exchange E/ProgressObserver____: onError
安卓工作室 android studio 汉化后,报错. 设置界面打不开. Android studio has been sinified and reported wrong.The setup interface cannot be opened. 安卓工作室 android studio 版本 2.3.3 Android studio version 2.3.3 汉化包版本 AndroidStudio_v2.0.0.20_resources_cn-v0.2-20170414.jar Lo
windows修改系统登录密码后,出现SQLserver服务无法启动,启动报错17051具体报错如下: 根据错误提示,去到windows的事件查看器.在win10上,右击左下角的菜单图标:然后依次点击Windows日志=>应用程序,根据来源找到MSSQLSERVER,再根据错误提示上的错误码找到17051: 双击后可查看日志信息,如下:至此,原因已经很明显了.安装的是SQL Server 2012评估版,180天的试用期后,MSSQLSERVER服务就无法启动,手动启动就报告17051错误.具体
用eclipse启动genymotion时有时候会报 The connection to adb is down, and a severe error has occured. You must restart adb and Eclipse. Please ensure that adb is correctly located at 'E:\setups\android\android-2.1_r01-windows\tools\adb.exe' and can be executed.
The following classes could not be instantiated:- android.support.v4.widget.DrawerLayout (Open Class, Show Exception) Tip: Use View.isInEditMode() in your custom views to skip code or show sample data when shown in the IDE 我使用了NavigationDrawer这个模块去创建
> get "all_couriers_on_the_job" (error) ERR Operation against a key holding the wrong kind of value #类型不对,所以报错,先查看值的类型: > type "all_couriers_on_the_job" hash > HGETALL "all_couriers_on_the_job" ) " ) "{\&qu
用mybaits 写一个关联查询 查询商品表关联商品规格表,并查询规格表中的数量.价格等,为了sql重用性,利用 association 节点 查询 结果并赋值报错 商品表的mapper文件为GooodsMapper.xml 规格表的mapper 文件为GoodsSpecificationsMapper.xml java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for m