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Java Study Notes day05 and Study Notes day05 1. Method overload A method with the same name is allowed in the same class, as long as the parameter list of the method is different. Different parameter lists: different parameter numbers, different parameter types, and different order. Public class MethodOverLoadDemo {public static void main (String [] args) {} public static void method (int a, int B) {} p

A Preliminary Study on the combination of primary keys and primary keys of SQL statements; a preliminary study on the primary keys of SQL statements I. Composite primary key The so-called composite primary key means that the primary key of your table contains more than one field and does not use auto-increment IDs without business meanings as the primary key.For example create table test ( name varchar(

Struts2 framework study notes 7: struts2 tag, struts2 Study Notes Three labels: 1. JSP: script. Expired to replace servlet 2. JSTL: Standard tag Library (core, format, SQL, xml). Only core libraries are eliminated. 3. Struts2 tag Library: Developed by the Struts2 Development Team, with more powerful functions Struts2 labels include common labels and UI labels. Common Tag: Control tag, data tag UI Tag: Form

Spring Study Notes 01 and spring Study Notes 011. Spring Introduction Spring is a lightweight solution for enterprises, including: dependency injection-based core mechanism, declarative Transaction Management Based on AOP, A collection of persistence layer technologies and excellent web mvc frameworks. Composition of the Spring framework: 2. Spring preparation 1) first download the Spring compressed file f

Struts2 Framework Study Notes 2: detailed configuration, struts2 Study Notes Core configuration file: Introduce other configuration files: Relative Path under src Constant Configuration: There is a default properties configuration file under the struts2 core package. When we need to modify it, Example 1: Create a configuration file by yourself. Struts. properties: struts.i18n.encoding=UTF-8 Exampl

Hibernate framework Study Notes 2: Detailed description of the configuration file, hibernate Study Notes Entity class: package domain;public class Customer { private Long cust_id; private String cust_name; private String cust_source; private String cust_industry; private String cust_level; private String cust_linkman; private String cust_phone; private String cust_mobile; publ

Php learning Note 8-questions caused by half quotation marks, learning Note 8-half quotation marks. Php study Note 8-questions caused by half-side quotation marks, learning Note 8-the system was reinstalled some time ago with half-side quotation marks and php was used again later, the apache + php + mysql environment has been re-built, which is caused by php study Note 8-questions caused by half quotation m

JAVA Study Notes (3) and java Study Notes @ SuppressWarnings ("resource") is used to suppress resource leakage warnings. For example, if I/O class is used, it is not closed.Set features:1) unordered, not random2) unique element3) No subscriptNote: Collection List Set is an interfaceNote: Because the Set does not have a subscript, the value of for cannot be used, and only the iterator can be used.HashSet: th

C ++ study notes 44: inheritance and derivation, study notes 44 Class combination, class inheritance Class combination (automobile, wheel, now you can combine the wheel class into the automobile class ;) Class inheritance (transportation tools and automobiles. At this time, automobiles can be derived from transportation tools ;) Combination: Common descriptions of has .. Inheritance: common description is .

Dapper Study Notes (2)-link reference, dapper Study Notes When studying the Dapper source code, we found SqlMapper In the Dapper NET45 class library. there is a blue arrow icon in front of the cs file and it is found that SqlMapper does not exist in the Dapper NET45 folder. cs file. The complete path in its file attribute points to SqlMapper In the Dapper NET40 folder. cs files, such: It is found that i

Data science Study Notes 1. science Study Notes Mutiple Plots on One Graphplt.plot(x, norm.pdf(x))plt.plot(x, norm.pdf(x, 1.0, 0.2)) #1.0 = mean, 0.2 = DSplt.show() Use plt. savefig to save the image as blank: Solution: Call plt. savefig before plt. show (). Scatter Plot From pylab import randnX = randn (10000) Y = randn (10000) plt. scatter (X, Y) # Pay Attention to the sequence. Draw a picture first and t

A Preliminary Study on Python crawlers (1) and a preliminary study on python Crawlers Background: I have learned basic Python syntax and a few regular expressions. It can be said that it is about equal to zero --. This should be a series of notes that record my crawler-related technical knowledge. It is very basic ~~ Programming Language: Python 3.6 Environment: Win7 Crawlers work in an understanding. crawl

Study Notes 2, struts2 Study Notes + =,-=, * =,/= Implies forced type conversion. In logical operations, the difference between and is: : No matter whether the left side is true or false, all operations are performed on the right side. : If the left side is false, the right side is not involved in the operation. If the left side is true, the right side is involved in the operation. An exclusive or operati

Python Study Notes 02 -- list and metadata, python Study Notes 02 --I. Introduction A Data Structure is a collection of data elements that are organized together in some way. Sequence is the most basic data structure in python. python contains six built-in sequences: List, tuples, strings, Unicode strings, buffer objects, and xrange objects.Ii. Use For example, if you want to use a list to store the user

Head first python cainiao Study Notes (chapter 4), python Study Notes 1, p124, error: NameError: name 'print _ lol 'is not defined To display in the file, you need to change the call of BIF print () to call the print_lol () function in the nester module in chapter 2. Therefore, you need to import the nester module. First, modify the print_lol () function in Chapter 2 nester module and update the module. T

Hua Gong retries and study notes, Hua Gong Study Notes Today is July 22, March 10, and there are 5 days before the review of the Chinese site. the Retest is performed on the database, and the questions are given by VS and SQL server. difficult. below are my notes for testing the machine. I. Database Design Create index Example: create index dept-index on policuctor (dept_name) Create view v as Example: cr

Java programming ideology Study Notes (1), programming ideology Study NotesObject Introduction 1. Abstract all programming languages provide abstract mechanisms. For example, assembly is a slight abstraction of the machine, and C language is an abstraction of assembly. In comparison, these languages have strong limitations in solving problems. Because they force you to think from the machine perspective. Pr

Spring boot document Study Notes day02 and Study Notes day02 1.Start to report an error. View debug $ Java-jar myproject-0.0.1-SNAPSHOT.jar-debug 2.Custom banner The banner that is printed on start up can be changed by addingbanner.txtFile to your classpath or by settingspring.banner.locationProperty to the location of such a file. If the file has an encoding other than UTF-8, you can setspring.banner.char

Java Study Notes (2), java Study NotesI. Common java Data Types Data Type Bytes occupied Note: Int 4 Char 2 Double 8 Float 4 Float a = 2f; (f or F must be added; otherwise, the default value is double) Boolean 1 Only true or false without 0 or non-0 String String type Long/short int 8/2

Rupeng Net study notes (8) CSS and pennet Study Notes css CSS I. Introduction to CSS 1. CSS (Cascading Style Sheet) Cascading Style Sheet is a computer language used to control the Display Effect of HTML content. 2. CSS pre-defines many style attributes related to the display effect, such as color and font-size. If you want the html content to display a certain effect, apply the corresponding CSS style attr