ما هو نمط RegEx (التعبير العادي)؟ كيفية استخدامه في جافا؟ مثال مرفق

نشرت: 2021-01-25
ما هو نمط RegEx (تعبير عادي)؟ كيفية استخدامه في جافا؟

ما هو RegEx؟

التعبير العادي هو نمط بحث عن String. java.util.regex فئات لمطابقة تسلسلات الأحرف مع الأنماط المحددة بواسطة التعبيرات العادية في Java.

يمكنك استخدام Regex من أجل:

  • نص البحث
  • استخراج النص
  • تعديل النص

دعونا نناقش بعض القواعد الأساسية:

فئات الأحرف في Regex:

1
2
3
4
5
6
7
.    Dot , any character ( may or may not match line terminators , read on )
\ d    A digit : [ 0 - 9 ]
\ D    A non - digit : [ ^ 0 - 9 ]
\ s    A whitespace character : [ \ t \ n \ x0B \ f \ r ]
\ S    A non - whitespace character : [ ^ \ s ]
\ w    A word character : [ a - zA - Z_0 - 9 ]
\ W    A non - word character : [ ^ \ w ]

المحددات الكمية في Regex:

1
2
3
4
5
6
*       Match 0 or more times
+       Match 1 or more times
?        Match 1 or 0 times
{ n }      Match exactly n times
{ n , }    Match at least n times
{ n , m }    Match at least n but not more than m times

Java Split أيضًا مثال Regex.

أحرف التعريف في Regex:

1
2
3
4
5
6
7
\    Escape the next meta - character ( it becomes a normal / literal character )
^   Match the beginning of the line
.    Match any character ( except newline )
$    Match the end of the line ( or before newline at the end )
|    Alternation ( ‘ or ’ statement )
( )    Grouping
[ ]    Custom character class

لنبدأ العمل على المثال. في المثال أدناه سوف ننتقل إلى 5 أمثلة مختلفة من Regex.

  1. كيفية تحليل نتيجة أمر الجهوزية في جافا
  2. تحقق مما إذا كان عنوان URL ينتهي بامتداد معين
  3. تحقق من وجود IP صالح
  4. مثال Regex's ReplaceAll ()
  5. اكتشف ما إذا كان رقم الضمان الاجتماعي صالحًا
Java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
package crunchify . com . tutorial ;
 
import java . util . regex . Matcher ;
import java . util . regex . Pattern ;
 
/**
* @author Crunchify.com
*
*/
 
public class CrunchifyRegexTutorial {
 
public static void main ( String [ ] args ) {
crunchifyLoadAndAverageRegex ( ) ;
System . out . println ( "\n==========================\n" ) ;
 
crunchifyFindUrlPattern ( ) ;
System . out . println ( "\n==========================\n" ) ;
 
crunchifyFindIPMatcher ( ) ;
System . out . println ( "\n==========================\n" ) ;
 
crunchifyRegexReplaceAllExample ( ) ;
System . out . println ( "\n==========================\n" ) ;
 
crunchifyValidateSSN ( ) ;
}
 
// Find if SSN is valid
private static void crunchifyValidateSSN ( ) {
String ssn1 = "123-45-6789" ;
String ssn2 = "123-456-789" ;
String pattern = "^(\\d{3}-?\\d{2}-?\\d{4})$" ;
 
if ( ssn1 . matches ( pattern ) ) {
System . out . println ( "SSN " + ssn1 + " is valid" ) ;
} else {
System . out . println ( "SSN " + ssn1 + " is NOT valid" ) ;
}
 
if ( ssn2 . matches ( pattern ) ) {
System . out . println ( "SSN " + ssn2 + " is valid" ) ;
} else {
System . out . println ( "SSN " + ssn2 + " is NOT valid" ) ;
}
 
}
 
// ReplaceAll() Example
private static void crunchifyRegexReplaceAllExample ( ) {
String find = "Java" ;
String line = "This is Crunchify.com Java Tutorial." ;
String replace = "Spring MVC" ;
 
Pattern p = Pattern . compile ( find ) ;
Matcher m = p . matcher ( line ) ;
 
// This line will find "Java" and replace it with "Spring MVC"
line = m . replaceAll ( replace ) ;
System . out . println ( line ) ;
 
}
 
// Check if valid IP present
private static void crunchifyFindIPMatcher ( ) {
Pattern validIPPattern = Pattern . compile ( "^(?:[0-9]{1,3}\\.){3}[0-9]{1,3}$" ) ;
System . out . println ( "192.abc.0.1 : " + validIPPattern . matcher ( "192.abc.0.1" ) . find ( ) ) ;
System . out . println ( "192.168.0.1 : " + validIPPattern . matcher ( "192.168.0.1" ) . find ( ) ) ;
}
 
// Check if URL ends with specific extension
private static void crunchifyFindUrlPattern ( ) {
String pattern = ".*\\.(ico|jpg|png|gif|tif|bmp|JPG|PNG|GIF|TIF|BMP)" ;
Pattern r = Pattern . compile ( pattern ) ;
 
Matcher m = r . matcher ( "https://crunchify.com/favicon.ico" ) ;
if ( m . find ( ) ) {
System . out . println ( "URL pattern found" ) ;
} else {
System . out . println ( "URL pattern doesn't found" ) ;
}
 
}
 
// How to Parse "uptime" command result in Java
public static void crunchifyLoadAndAverageRegex ( ) {
Pattern uptimePattern = Pattern . compile ( "^.*\\s+load\\s+average:\\s+([\\d\\.]+),\\s+([\\d\\.]+),\\s+([\\d\\.]+)$" ) ;
 
String output = " 10:17:32 up 189 days, 18:49,  5 user,  load average: 2.07, 1.11, 1.16" ;
Matcher m = uptimePattern . matcher ( output ) ;
 
if ( m . matches ( ) ) {
final double crunchify1MinuteLoadAvg = Double . parseDouble ( m . group ( 1 ) ) ;
final double crunchify5eMinuteloadAvg = Double . parseDouble ( m . group ( 2 ) ) ;
final double crunchify15MinuteLoadAvg = Double . parseDouble ( m . group ( 3 ) ) ;
 
System . out . println ( "Load Average 1 min: " + crunchify1MinuteLoadAvg ) ;
System . out . println ( "Load Average 5 min: " + crunchify5eMinuteloadAvg ) ;
System . out . println ( "Load Average 15 min: " + crunchify15MinuteLoadAvg ) ;
} else {
System . out . println ( "no matches found" ) ;
}
 
}
}

انتاج:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Load Average 1 min : 2.07
Load Average 5 min : 1.11
Load Average 15 min : 1.16
 
==========================
 
URL pattern found
 
==========================
 
192.abc.0.1 : false
192.168.0.1 : true
 
==========================
 
This is Crunchify . com Spring MVC Tutorial .
 
==========================
 
SSN 123 - 45 - 6789 is valid
SSN 123 - 456 - 789 is NOT valid

كيف تتحقق من قوة كلمة المرور باستخدام Java Code؟

تجد أدناه الشروط الخاصة بي:

1
2
3
4
5
6
#   must contains one digit from 0-9
( ? = . * [ a - z ] ) must contains one lowercase characters
( ? = . * [ A - Z ] ) must contains one uppercase characters
( ? = . * [ ! @ #$%]) must contains one special symbols in the list "!@#$%"
. match anything with previous condition checking
{ 8 , 25 } length at least 8 characters and maximum of 25

CrunchifyPasswordVerification.java

Java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
package crunchify . com . tutorial ;
 
import java . util . ArrayList ;
import java . util . List ;
import java . util . regex . Matcher ;
import java . util . regex . Pattern ;
 
/**
* @author Crunchify.com
*
*/
public class CrunchifyPasswordVerification {
public static void main ( String [ ] args ) {
 
String pattern = "((?=.*[@!#$%])(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{8,22})" ;
Pattern r = Pattern . compile ( pattern ) ;
 
List <String> input = new ArrayList <String> ( ) ;
input . add ( "Crunchify" ) ;
input . add ( "Crunchify123#" ) ;
input . add ( "crunchify123#" ) ;
input . add ( "crunchify** " ) ;
input . add ( "Crunchify123!!" ) ;
 
for ( String password : input ) {
Matcher m = r . matcher ( password ) ;
if ( m . matches ( ) )
System . out . println ( "Password: " + password + " is valid" ) ;
else
System . out . println ( "Password: " + password + " is NOT valid" ) ;
}
 
}
}

نتيجة:

1
2
3
4
5
Password: Crunchify is NOT valid
Password: Crunchify123# is valid
Password: crunchify123# is NOT valid
Password: crunchify**  is NOT valid
Password: Crunchify123!! is valid