tcp supplement

throws to throw the declaration.Custom exceptionsCustom exception classes, you must base existing exception classesTypically, exception or runtimeexception are inherited, respectively, to declare a check-time exception and a run-time exception.and rewrite its getmessage () method.Use of log4j logsUse of log4j:1. Import Log4j.jar2. Create the Log4j.propetites profile under SRC peer3. Get a Log object through Logger.getlogger () in the class that needs to print the log4, respectively call differe

Note: Time complexity: The time required to complete a program;Space complexity: The amount of memory required to complete a program;1. Bubble Sort: 22 comparison, if the previous one is larger than the latter, then the interchange position, after each cycle comparison, the last one is always the largest, the next round of comparison, it will not participate.Eg:function Sort (Array) {for (var i = 0; i for (var j = 0; jif (Array[j] > array[j+1]) {　　　　　　　　　　var SMAP = array[j]; Assign a large valu

handledClerk.addproduct (); } }}The same consumer I will not write in detail, and the same as above.publicclass Consumer implements Runnable{ ...... publicvoidrun(){ .... clerk.getProduct(); }}To write the Clerk class: Public class clerk{ intProduct//This is the shared data we are working on Public synchronized void addproduct(){if(Product >= -){Try{Wait ();//production of more than 20, we wait for consumers to take away the reproduction}Catch(){ ....

1. A small problem:Deleting a list element during a loop will be different from the expected result, but will not cause an errorLis =[11,22,33,44,55] forIinchRange (len (LIS)):#When you use range () for the first time, the value is saved by default, and the value in the subsequent loop value is fixed to dead. Print(i)delLis[i]Print(LIS)delLis[1::2]Print(LIS) forIinchRange (0, 2): Print(I,type (i))delLis[i]Print(LIS)View CodeFor dictionary dict: Cannot delete dictionary key value pair durin

}") Publicstring Hello1 (@PathVariable string put) {returnput; }@RequestMapping ("/free/{put}") PublicString Hello2 (@PathVariable ("put") StringGet) { return Get; }Two methods:1. Pass the path parameter put to the method parameter put, note that the two put to be consistent, that is, the path parameter name is put, the function parameter name is also put;[Email protected] ("put") gets the value of the path parameter named put and passes it to the method parameter get, where the f

; } }) In this way, Google and Firefox can be compatible with the number of input restrictions. Of course, if the paste copy in the past can not be controlled, so after the loss should also do a check.2. About JS Digital size comparison problem:　　　　1 var first = ' 1234 '; 2 var = ' second '; 3 Console.log (first This is because this is a string comparison, according to a letter-by-letter comparison, comparing the first letter 1, equal, the second letter 3>2, so true;Usually use jquer

Cuiqingcai "Python3 Network crawler development Combat" finishingGreed and non-greedImport'Hello 12345678 word_this is a Regex Demo'= Re.match (' ^he.* (\d+). *demo$', content)print(Result.group (1))Originally intended to take out 12345678, butRun Result: 8Greedy match pattern:. * Matches as many characters as possible.. * After (\d+) match at least one number, no specific number specified. So. * Match as many characters as possible, match 1234567, and give \d+ a result that satisfies only 8 of

= {}2) dic = Dict ()3) dic = Dict.fromkey (key, value) #如果没有值, default is NoneTrap question TwoDic1 = Dict.fromkeys ([],[])print(dic1) dic1[1].append ('Alex ')print(dic1) #print(ID (dic1[1))) Print(ID (dic1[2)))print(ID (dic1[3)))Conversion of data typesint STR BOOL Three conversionsstr STR Dict.keys () dict.values () dict.items () list ()Tuple Dict---> Liststring conversion to list split# str---> List# S1 = ' Alex Wusir taibai '# L1 = S1.split ()# print (L1)# list ---> str the eleme

① in terms of parameters:Map () Function:Map () contains two parameters, the first one is a function, the second is a sequence (list or tuple). Where a function (that is, a function of the first parameter position of a map) can receive one or more parameters.Reduce () function:The first parameter of reduce () is a function, and the second is a sequence (list or tuple). However, its function must receive two parameters.② from the numerical effect on the transfer in terms of:Map () is the function

)--->true string A word typeface multiply, out of the 20 range is the same two memory addresses: S1='h'* +S2='h'* +Print (S1 isS2)--->falseOther data typesThe list dic tuple set has no small data pool conceptTake list For example: L1=[1,]l2=[1,]print (L1 is L2)--- >falseCodingAsciiNo Chinese only English one byte (bytes) ==8 digit (bit)UnicodeEnglish: 32 bits 4 bytesEnglish: 32 bits 4 bytesUtf-8English: 8 bits 1 bytesEnglish: 24 bits 3 bytesGBKEnglish: 8 bits 1 bytesEnglish: 16 bits 2 bytes1.

' 1.int 2.str 3. Meta-zu tuple Tu = (' name ') TU1 = (' name ',) Print (Tu,type (TU)) Print (Tu1,type (TU1)) 4. List When you loop through a list, if you delete some or some elements in the loop, the number of elements in the list changes, causing the index to change and error-prone 5. Dictionary When a loop dictionary is deleted, if you delete some or some key-value pairs in the loop, the number of key-value pairs in the dictionary changes. Changes in length, error prone 6. Convert

in the previous article, which is not covered here).Five, proceed to line 18th and call the FN function--fn (10) again. Generates the FN (5) context and presses the stack and sets it to the active state. At this point, however, the context of FN (5) is still in memory-there are two contexts in a single scope. Here, the emphasis has been told, and then the scene here will not repeat.The goal is to hope that we can use this example to clarify the context and scope of the relationship. Of course,

One, depth copySee Copy day19-1.pyS=[1, ' Zhangsan ', ' Lisi '] #s2是s的拷贝s2 =s.copy () #打印s2和s是一样的print (S2) #修改s2s2 [0]=2# print S is the unchanged print (s) #打印s2因为修改了所以有变化print (S2) [1, ' Zhangsan ', ' Lisi '] [1, ' Zhangsan ', ' Lisi '] [2, ' Zhangsan ', ' Lisi ']If the modified element is a list, the source list also changes day19-2.pys = [[up], ' Zhangsan ', ' Lisi ']s3=s.copy () print (S3) print (s) s3[0][1]=3# modify S3 inside list element after source list also corresponds to change prin

Read Old Luo's "Only through the crash address to find the source code error Line" (hereinafter referred to as "Luo Wen") after a article, feel that the text can still learn a lot of things. However, there are some improper statements, and some of the operation is too cumbersome place. To this end, I learned this article, in many experiments on the basis of the text of some of the contents of the supplement and improvement, I hope to debug the program

construction, its main keywords quickly jumped to Baidu home page. The customer's business is bullish, up to the point where the business has not been done. But it temporarily stopped advertising to Baidu, concentrate on digestion old list. In a few days after the customer suspended advertising, its natural ranking will be hit, and back to the previous state, that is, the 2nd, 3, 4 pages, but also because the base of the customer site is good, may be too close after also is too obvious, 2, 3, 4

,table2 b where a.id=b.idb:select * from Table1 Cross Join Table2 wheRe Table1.id=table2.id (note: After cross join conditions can only be used where, cannot be used on) three, crossed connections (full) 1. Concept: A cross join without a WHERE clause will produce a Cartesian product of the table involved in the join. The number of rows in the first table multiplied by the number of rows in the second table equals the size of the Cartesian product result set. (Table1 and table2 cross-joins gener

Tags: relationship DB2 problem complete ble run SQL very saveDatabase features: Mass storage, fast lookup, concurrency problem control, security, data integrity (the data stored in the database is correct, real).Table: [Relationships] in a relational database are tables. Different brands of DBMS have their own different features: MySQL (fast, suitable for the data requirements are not very rigorous place, removed many small and medium-sized enterprises infrequently used features),MSSQLServer (an

SqlException BEGIN--ERROR set p_return_code = 1; Rollback END; DECLARE exit handler for SQLWarning BEGIN--WARNING set p_return_code = 2; Rollback END; START TRANSACTION; DELETE from TB1; #执行失败 INSERT INTO blog (name,sub_time) VALUES (' yyy ', now ()); COMMIT; --SUCCESS Set P_return_cOde = 0; #0代表执行成功END//delimiter; #在mysql中调用存储过程set @res =123;call P5 (@res); select @res; Call stored procedure Cursor.callproc (' P5 ', (123,)) print (Cursor.fetchall ()) #查询s

MySQL Time function--Get Current dateSelectcurrent_date ();--Get current TimeSelectcurrent_time ();--gets the current date and timeSelectNow ();--get datetime year, month, daySelectYear (now ());--yearsSelectMonth (now ());--MonthSelectDay (now ());--days--returns the date portion of a datetimeSelectDate (now ());--Add date or time to datetimeSelectDate_add (now (), interval1Day);--the day after the current datetimeSelectDate_add (now (), Interval-1Day);--the day before the current datetimeSelec

specified fractional number before or after it, and it is truncated altogether.Its specific syntax format is as followsTRUNC (Number[,decimals])whichNumber to be intercepted and processedDecimals indicates the number of digits after the decimal point to be retained. Optional, ignore it to truncate all the decimal partsHere's how this function is used:TRUNC (89.985,2) =89.98TRUNC (89.985) =89TRUNC (89.985,-1) =80Note: The second parameter can be a negative number, which means that the portion of