Dark Horse programmer-28th days of Java Basics

 

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1: Regular Expression (understanding)

(1) A regular expression is a string that meets certain rules.
(2) Rules to be mastered
1: character
X characters x
\ Backslash character
\ N linefeed

2: character class
[ABC] A, B, or C
[^ ABC] any character except A, B, or C
[A-Za-Z] letters from A to Z or from A to Z are included
[0-9] 0-9 numeric characters

3: pre-defined character class
. Any character
\ D Number: [0-9]
\ D non-numeric: [^ 0-9]
\ W word character: [a-zA-Z_0-9]
Characters: English letters, numbers, and underscores
\ W non-word characters: [^ \ W]

4: Border Matters
^ Beginning of a row
$ End of a row
\ B word boundary

5: greedy quantifiers
X? X, neither once nor once
X * X, zero or multiple times
X + X, once or multiple times
X {n} X, EXACTLY n times
X {n,} X, at least N times
X {n, m} X, at least N times, but not more than m times

6: group concept
If this is an expression (a) (B (c), it should be divided into the following groups according to the group concept:
Group 1: (a) (B (c ))
Group 2:
Group 3: B (c)
Group 4: c
(3) Use of Regular Expressions
A: Judgment Function
String split ()
C: replacement function
String -- replaceall ()
D. Obtain the function.
Pattern
Compile
Matcher
Find
Group
(4) case studies
Email Verification
I want to learn Programming
IP address sorting

2: Reflection (understanding)
(1) Reflection uses all its members through the Class Object of the runtime class.
(2) three methods for obtaining Class Object
A: getclass () method of Object Class
B: A static property. Class
C: static method forname of class
(3) Use of reflection
A: Constructor
B: member variables
C: Member Method
(4) case studies
A: Use the configuration file to run the methods in the class.

B: Reflection checks during compilation

 

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