Commonly used regular expressions in java

"^/d+$" //Non-negative integer (positive integer + 0)

"^[0-9]*[1-9][0-9]*$" //Positive Integer

"^((-/d+)|(0+))$" //Non-positive integer (negative integer + 0)

"^-[0-9]*[ 1-9][0-9]*$" //Negative integer

"^-?/d+$" //Integer

"^/d+(/./d+)? $" //Non-negative floating point number (positive floating point number + 0)

"^(([0-9]+/.[0-9]*[1-9][0-9]* )|([0-9]*[1-9][0-9]*/.[0-9]+)|([0-9]*[1-9][0-9]*)) $" //Positive floating point number

"^((-/d+(/./d+)?)|(0+(/.0+)?))$" //Non-positive floating point number ( Negative floating point number + 0)

"^(-(([0-9]+/.[0-9]*[1-9][0-9]*)|([0-9 ]*[1-9][0-9]*/.[0-9]+)|([0-9]*[1-9][0-9]*)))$" // Negative float Point number

"^(-?/d+)(/./d+)?$" //Floating point number

"^[A-Za-z]+$" //From 26 A string composed of 26 English letters

"^[A-Z]+$" // A string composed of 26 uppercase English letters

"^[a-z]+$" // A string consisting of 26 lowercase English letters

"^[A-Za-z0-9]+$" //A string consisting of numbers and 26 English letters

"^/w+$" //A string consisting of numbers, 26 English letters or underscores

"^[/w-]+(/.[/w-]+)*@[/w -]+(/.[/w-]+)+$"　　　 //email address

"^[a-zA-z]+://(/w+(-/w+)*)( /.(/w+(-/w+)*))*(/?/S*)?$"　 //url

/^(d{2}|d{4})-((0 ([1-9]{1}))|(1[1|2]))-(([0-2]([1-9]{1}))|(3[0|1])) $/ // Year-month-day

/^((0([1-9]{1}))|(1[1|2]))/(([0-2]( [1-9]{1}))|(3[0|1]))/(d{2}|d{4})$/ // month/day/year

"^( [w-.]+)@(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.)|(([w -]+.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(]?)$" //Emil

"( d+-)?(d{4}-?d{7}|d{3}-?d{8}|^d{7,8})(-d+)?" //Phone number

"^(d{1,2}|1dd|2[0-4]d|25[0-5]).(d{1,2}|1dd|2[0-4]d|25[0 -5]).(d{1,2}|1dd|2[0-4]d|25[0-5]).(d{1,2}|1dd|2[0-4]d|25 [0-5])$" //IP address

regular expression matching Chinese characters: [/u4e00-/u9fa5]

matches double-byte characters (including Chinese characters) :[^/x00-/xff]

Regular expression matching blank lines:/n[/s| ]*/r

Regular expression matching HTML tags:/< (.*)>.*|<(.*) //>/

Regular expression matching leading and trailing spaces: (^/s*)|(/s*$)

Regular expression matching email addresses: /w+([-+.]/w+)*@/w+([-.]/w+)*/./w+([-.]/w+)*

Regular expression matching URL: ^[a-zA-z]+://(//w+(-//w+)*)(//.(//w+(-//w+) *))*(//?//S*)?$

Is the matching account legal (starting with a letter, 5-16 bytes allowed, alphanumeric underscores allowed): ^[a-zA-Z] [a-zA-Z0-9_]{4,15}$

Matches domestic phone numbers: (/d{3}-|/d{4}-)?(/d{8}|/ d{7})?

matches Tencent QQ number: ^[1-9]*[1-9][0-9]*$

metacharacters and their regular expressions Behavior in context:

/ Marks the next character as a special character, or a literal character, or a backreference, or an octal escape character.

^ Matches the beginning of the input string. If the Multiline property of the RegExp object is set, ^ also matches the position after '/n' or '/r'.

$ Matches the end of the input string. If the Multiline property of the RegExp object is set, $ also matches the position before '/n' or '/r'.

* Matches the preceding subexpression zero or more times.

+ Matches the preceding subexpression one or more times. + is equivalent to {1,}.

? Matches the preceding subexpression zero or one time. ? Equivalent to {0,1}.

{n} n is a non-negative integer that matches a certain number of n times.

{n,} n is a non-negative integer, matched at least n times.

{n,m} m and n are both non-negative integers, where n <= m. Match at least n times and at most m times. There cannot be a space between the comma and the two numbers.

? When this character immediately follows any of the other qualifiers (*, +, ?, {n}, {n,}, {n,m}), the matching pattern is non-greedy. Non-greedy mode matches as little of the searched string as possible, while the default greedy mode matches as much of the searched string as possible.

. Matches any single character except "/n". To match any character including '/n', use a pattern like '[./n]'.

(pattern) Match pattern and get this match.

(?:pattern) matches pattern but does not obtain the matching result, which means that this is a non-acquisition match and is not stored for later use.

(?=pattern) Forward lookup, match the search string at the beginning of any string matching pattern. This is a non-fetch match, that is, the match does not need to be fetched for later use.

(?!pattern) Negative lookup, opposite to (?=pattern)

x|y matches x or y.

[xyz] character set.

[^xyz] Negative value character set.

[a-z] Character range, matches any character within the specified range.

[^a-z] Negative character range, matches any character that is not within the specified range.

/b matches a word boundary, which refers to the position between a word and a space.

/B matches non-word boundaries.

/cx matches the control character specified by x.

/d matches a numeric character. Equivalent to [0-9].

/D matches a non-numeric character. Equivalent to [^0-9].

/f matches a form feed character. Equivalent to /x0c and /cL.

/n matches a newline character. Equivalent to /x0a and /cJ.

/r matches a carriage return character. Equivalent to /x0d and /cM.

/s matches any whitespace character, including spaces, tabs, form feeds, etc. Equivalent to [/f/n/r/t/v].

/S matches any non-whitespace character. Equivalent to [^ /f/n/r/t/v].

/t matches a tab character. Equivalent to /x09 and /cI.

/v matches a vertical tab character. Equivalent to /x0b and /cK.

/w matches any word character including an underscore. Equivalent to '[A-Za-z0-9_]'.

/W matches any non-word character. Equivalent to '[^A-Za-z0-9_]'.

/xn matches n, where n is the hexadecimal escape value. The hexadecimal escape value must be exactly two digits long.

/num matches num, where num is a positive integer. A reference to the match obtained.

/n identifies an octal escape value or a backreference. If /n is preceded by at least n fetched subexpressions, n is a backreference. Otherwise, if n is an octal number (0-7), then n is an octal escape value.

/nm Identifies an octal escape value or a backreference. If /nm is preceded by at least nm fetched subexpressions, nm is a backreference. If /nm is preceded by at least n gets, then n is a backreference followed by the literal m. If none of the previous conditions are true, then /nm matches the octal escape value nm if n and m are both octal digits (0-7).

/nml If n is an octal digit (0-3), and m and l are both octal digits (0-7), then matches the octal escape value nml.

/un matches n, where n is a Unicode character represented by four hexadecimal digits.

Regular expression to match Chinese characters: [u4e00-u9fa5]

Match double-byte characters (including Chinese characters): [^x00-xff]

Match Regular expression for empty lines: n[s| ]*r

Regular expression for matching HTML tags: /<(.*)>.*|<(.*) />/

Regular expression matching leading and trailing spaces: (^s*)|(s*$)

Regular expression matching email address: w+([-+.]w+)*@ w+([-.]w+)*.w+([-.]w+)*

Regular expression matching URL: http://([w-]+.)+[w-] +(/[w- ./?%&=]*)?

Use regular expressions to limit the input content of the text box in the web form:

Use regular expressions to limit only input Chinese: onkeyup="value=value.replace(/[^u4E00-u9FA5]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^ u4E00-u9FA5]/g,''))"

Use regular expressions to limit the input of only full-width characters: onkeyup="value=value.replace(/[^uFF00-uFFFF]/g,'' )" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^uFF00-uFFFF]/g,''))"

Use regular expressions to limit Only numbers can be entered: onkeyup="value=value.replace(/[^d]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[ ^d]/g,''))"

Use regular expressions to limit input to numbers and English only: onkeyup="value=value.replace(/[W]/g,'') "onbeforepaste ="clipboardData.setData('text',clipboardData.getData('text').replace(/[^d]/g,''))"

　********** *************************************************** ******************************************

Only numbers can be entered : "^[0-9]*$".

Only n-digit numbers can be entered: "^/d{n}$".

You can only enter a number with at least n digits: "^/d{n,}$".

Only m~n digits can be entered:. "^/d{m,n}$"

Only numbers starting with zero and non-zero can be entered: "^(0|[1-9][0-9]*)$".

Only positive real numbers with two decimal places can be entered: "^[0-9]+(.[0-9]{2})?$".

Only positive real numbers with 1 to 3 decimal places can be entered: "^[0-9]+(.[0-9]{1,3})?$".

Only non-zero positive integers can be entered: "^/+?[1-9][0-9]*$".

Only non-zero negative integers can be entered: "^/-[1-9][]0-9"*$.

Only characters with a length of 3 can be entered: "^.{3}$".

Only a string consisting of 26 English letters can be entered: "^[A-Za-z]+$".

Only a string consisting of 26 uppercase English letters can be entered: "^[A-Z]+$".

Only a string consisting of 26 lowercase English letters can be entered: "^[a-z]+$".

Only a string consisting of numbers and 26 English letters can be entered: "^[A-Za-z0-9]+$".

Only a string consisting of numbers and 26 English letters can be entered A string composed of English letters or underscores: "^/w+$".

Verify user password: "^[a-zA-Z]/w{5,17}$" The correct format is: starting with a letter, the length is between 6 and 18, and can only contain characters and numbers. and underline.

Verify whether it contains characters such as ^%&',;=?$/": "[^%&',;=?$/x22]+".

Only Chinese characters can be entered : "^[/u4e00-/u9fa5]{0,}$"

Verify email address: "^/w+([-+.]/w+)*@/w+([-.]/w+ )*/./w+([-.]/w+)*$".

Verify InternetURL: "^http://([/w-]+/.)+[/w-]+ (/[/w-./?%&=]*)?$".

Verification phone number: "^(/(/d{3,4}-)|/d{3.4}-)?/d{7,8}$" The correct format is: "XXX-XXXXXXX", " XXXX-XXXXXXXX", "XXX-XXXXXXX", "XXX-XXXXXXXX", "XXXXXXX" and "XXXXXXXX".

Verify ID number (15 or 18 digits): "^/d{15}|/d{18}$".

Verify the 12 months of a year: "^(0?[1-9]|1[0-2])$" The correct format is: "01"～"09" and "1"～ "12".

Verify the 31 days of a month: "^((0?[1-9])|((1|2)[0-9])|30|31)$"The correct format is;" 01"～"09" and "1"～"31".

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