https://stackoverflow.com/questions/129077/not-in-clause-and-null-valuesThisissuecameupwhenIgotdifferentrecordscountsforwhatIthoughtwereidenticalqueriesoneusing...

 ValueTuple需要通过NuGet安装System.ValueTuplehttps://docs.microsoft.com/en-us/dotnet/csharp/tuples?view=netframework-4.7.2https://docs.microsoft.com/en-us/dotnet...

https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask-1?view=netcore-2.2https://devblogs.microsoft.com/dotnet/understanding-the-whys-what...

Whenprogramming,Ioftenfindit'susefultorepresentthingsasacompound混合物.A2Dcoordinateconsistsofanxvalueandyvalue.Anamountofmoneyconsistsofanumberandacurrency.Adater...

ThecompilerreplacesnullcomparisonswithacalltoHasValue,sothereisnorealdifference.Justdowhicheverismorereadable/makesmoresensetoyouandyourcolleagues. ...

Allvariables(andcontrols)aredisposedattheendofthepage'slifecycle.Soyouneedawaytopersistyourvariable,e.g.intheViewState.publicintDepartmentID{get{if(ViewState["d...

https://stackoverflow.com/questions/14956027/how-to-pass-values-across-the-pages-in-asp-net-without-using-sessionYoucanpassvaluesfromonepagetoanotherbyfollowing...

Averydetailedexplanationaboutcopying,passingandcomparingbyvalueandbyreferenceisinthischapterofthe"JavaScript:TheDefinitiveGuide"book./Beforeweleavethetopicofman...

Array.prototype.values=function(){leti=0;letself=thisreturn{next(){constdone=i>=self.lengthconstvalue=done?undefined:self[i++]return{value,done}}}}constcolor...

如果java后台准备用Servlet来实现，可以直接在doPost()或者doGet()中使用如下语句：request.setCharacterEndoding("UTF-8");//为了保证form有中文时不会出现乱码Stringname=request.getParameter("name");Stringvalu...

Key-Value是用一个不可重复的key集合对应可重复的value集合。（典型的例子是字典：通过页码的key值找字的value值）。例子：key1—value1;key2—value2;key3—value3.SortedMap：如果一个Map可以根据key值排序，则称其为SortedMap。（如字典）!!注意数组和...

今天写的Configuration类的@Value属性值为null@ConfigurationpublicclassMybatisConfigurer{@Value("${spring.datasource.url}")privateStringdbUrl;@Value("${spring.datasource.use...

今天使用mybatis出现了异常java.sql.SQLException:Zerodatevalueprohibited查了下原因mysql文档上写着Datetimes withall-zerocomponents(0000-00-00...):Thesevaluescannotberepresentedr...

12345678910111213141516@Testpublic void testMap2List() throws Exception{    Map<String,String>map= new H...

map是用来存放<key,value>键值对的数据结构，可以很方便快速的根据key查到相应的value。假如存储学生和其成绩（假定不存在重名，当然可以对重名加以区分），我们用map来进行存储就是个不错的选择。我们这样定义，map<string,int>，其中学生姓名用string类型，作为Key...