1.I字W串?/strong>
使用函数: StringUtils.isBlank(testString)
函数介绍: 当testString为空,长度为零或者仅q白字W?whitespace)l成?q回True;否则q回False
例程:
String test = "";
String test2 = "\n\n\t";
String test3 = null;
String test4 = "Test";
System.out.println( "test blank? " + StringUtils.isBlank( test ) );
System.out.println( "test2 blank? " + StringUtils.isBlank( test2 ) );
System.out.println( "test3 blank? " + StringUtils.isBlank( test3 ) );
System.out.println( "test4 blank? " + StringUtils.isBlank( test4 ) );
输出如下:
test blank? true
test2 blank? true
test3 blank? true
test4 blank? False
函数StringUtils.isNotBlank(testString)的功能与StringUtils.isBlank(testString)相反.
2.清除I白字符
使用函数: StringUtils.trimToNull(testString)
函数介绍:清除掉testString首尾的空白字W?如果仅testString全由I白字符
(whitespace)l成则返回null
例程:
String test1 = "\t";
String test2 = " A Test ";
String test3 = null;
System.out.println( "test1 trimToNull: " + StringUtils.trimToNull( test1 ) );
System.out.println( "test2 trimToNull: " + StringUtils.trimToNull( test2 ) );
System.out.println( "test3 trimToNull: " + StringUtils.trimToNull( test3 ) );
输出如下:
test1 trimToNull: null
test2 trimToNull: A Test
test3 trimToNull: null
注意Q函数StringUtils.trim(testString)?br /> StringUtils.trimToNull(testString)功能cMQ但testStringq白字W?br /> (whitespace)l成时返回零长度字符丌Ӏ?/p>
3.取得字符串的~写
使用函数: StringUtils.abbreviate(testString,width)和StringUtils.abbreviate(testString,offsetQwidth)
函数介绍:在给定的width内取得testString的羃?当testString的长度小于width则返回原字符?
例程:
String test = "This is a test of the abbreviation.";
String test2 = "Test";
System.out.println( StringUtils.abbreviate( test, 15 ) );
System.out.println( StringUtils.abbreviate( test, 5,15 ) );
System.out.println( StringUtils.abbreviate( test2, 10 ) );
输出如下:
This is a te...
...is a test...
Test
4.劈分字符?/strong>
使用函数: StringUtils.split(testString,splitChars,arrayLength)
函数介绍:splitChars中可以包含一pd的字W串来劈分testString,q可以设定得
到数l的长度.注意讑֮长度arrayLength和劈分字W串间有抵触关系,一般情况下
不要讑֮长度.
例程:
String input = "A b,c.d|e";
String input2 = "Pharmacy, basketball funky";
String[] array1 = StringUtils.split( input, " ,.|");
String[] array2 = StringUtils.split( input2, " ,", 2 );
System.out.println( ArrayUtils.toString( array1 ) );
System.out.println( ArrayUtils.toString( array2 ) );
输出如下:
{A,b,c,d,e}
{Pharmacy,basketball funky}
5.查找嵌套字符?/strong>
使用函数:StringUtils.substringBetween(testString,header,tail)
函数介绍Q在testString中取得header和tail之间的字W串。不存在则返回空
例程Q?br />
String htmlContent = "ABC1234ABC4567";
System.out.println(StringUtils.substringBetween(htmlContent, "1234", "4567"));
System.out.println(StringUtils.substringBetween(htmlContent, "12345", "4567"));
输出如下Q?br />
ABC
null
6.去除N换行W?/strong>
使用函数:StringUtils.chomp(testString)
函数介绍:去除testStringN的换行符
例程:
String input = "Hello\n";
System.out.println( StringUtils.chomp( input ));
String input2 = "Another test\r\n";
System.out.println( StringUtils.chomp( input2 ));
输出如下:
Hello
Another test
7.重复字符?/strong>
使用函数:StringUtils.repeat(repeatString,count)
函数介绍:得到repeatString重复countơ后的字W串
例程:
System.out.println( StringUtils.repeat( "*", 10));
System.out.println( StringUtils.repeat( "China ", 5));
输出如下:
**********
China China China China China
其他函数:StringUtils.center( testString, count,repeatString );
函数介绍:把testString插入repeatString重复多次后的字符串中?得到字符?br />
的总长为count
例程:
System.out.println( StringUtils.center( "China", 11,"*"));
输出如下:
***China***
8.颠倒字W串
使用函数:StringUtils.reverse(testString)
函数介绍:得到testString中字W颠倒后的字W串
例程:
System.out.println( StringUtils.reverse("ABCDE"));
输出如下:
EDCBA
9.判断字符串内容的cd
函数介绍:
StringUtils.isNumeric( testString ) :如果testString全由数字l成q回True
StringUtils.isAlpha( testString ) :如果testString全由字母l成q回True
StringUtils.isAlphanumeric( testString ) :如果testString全由数字或数字组
成返回True
StringUtils.isAlphaspace( testString ) :如果testString全由字母或空格组
成返回True
例程:
String state = "Virginia";
System.out.println( "Is state number? " + StringUtils.isNumeric(
state ) );
System.out.println( "Is state alpha? " + StringUtils.isAlpha( state )
);
System.out.println( "Is state alphanumeric? " +StringUtils.isAlphanumeric( state ) );
System.out.println( "Is state alphaspace? " + StringUtils.isAlphaSpace( state ) );
输出如下:
Is state number? false
Is state alpha? true
Is state alphanumeric? true
Is state alphaspace? true
10.取得某字W串在另一字符串中出现的次?br />
使用函数:StringUtils.countMatches(testString,seqString)
函数介绍:取得seqString在testString中出现的ơ数,未发现则q回?br />
例程:
System.out.println(StringUtils.countMatches( "Chinese People", "e"
));
输出:
4
11.部分截取字符?/strong>
使用函数:
StringUtils.substringBetween(testString,fromString,toString ):取得两字W?br />
之间的字W串
StringUtils.substringAfter( ):取得指定字符串后的字W串
StringUtils.substringBefore( )Q取得指定字W串之前的字W串
StringUtils.substringBeforeLast( )Q取得最后一个指定字W串之前的字W串
StringUtils.substringAfterLast( )Q取得最后一个指定字W串之后的字W串
函数介绍Q上面应该都讲明白了吧?br />
例程Q?br />
String formatted = " 25 * (30,40) [50,60] | 30";
System.out.print("N0: " + StringUtils.substringBeforeLast( formatted, "*" ) );
System.out.print(", N1: " + StringUtils.substringBetween( formatted, "(", "," ) );
System.out.print(", N2: " + StringUtils.substringBetween( formatted, ",", ")" ) );
System.out.print(", N3: " + StringUtils.substringBetween( formatted, "[", "," ) );
System.out.print(", N4: " + StringUtils.substringBetween( formatted, ",", "]" ) );
System.out.print(", N5: " + StringUtils.substringAfterLast( formatted, "|" ) );
输出如下Q?br />
N0: 25 , N1: 30, N2: 40, N3: 50, N4: 40) [50,60, N5: 30
一、数l{成字W串Q?
1?数l中的字W{换ؓ一个字W串
数l中的字W{换ؓ一个字W串
@param strToConv 要{换的字符?,默认以逗号分隔
@return q回一个字W串
String[3] s={"a","b","c"}
StringUtil.convStringQs)="a,b,c"
2?static public String converString(String strToConv)
@param strToConv 要{换的字符?,
@param conv 分隔W?默认以逗号分隔
@return 同样q回一个字W串
String[3] s={"a","b","c"}
StringUtil.convStringQs,"@")="a@b@c"
static public String converString(String strToConv, String conv)
二、空值检：
3?
Checks if a String is empty ("") or null.
判断一个字W串是否为空Q空g非空处理?StringUtils.isEmpty(null) = true StringUtils.isEmpty("") = true StringUtils.isEmpty(" ") = false StringUtils.isEmpty("bob") = false StringUtils.isEmpty(" bob ") = false
NOTE: This method changed in Lang version 2.0.
It no longer trims the String.
That functionality is available in isBlank().
@param str the String to check, may be null
@return true if the String is empty or null
public static boolean isEmpty(String str)
三、非I处理：
4?
Checks if a String is not empty ("") and not null.
判断一个字W串是否非空Q空g非空处理. StringUtils.isNotEmpty(null) = false StringUtils.isNotEmpty("") = false StringUtils.isNotEmpty(" ") = true StringUtils.isNotEmpty("bob") = true StringUtils.isNotEmpty(" bob ") = true
@param str the String to check, may be null
@return true if the String is not empty and not null
public static boolean isNotEmpty(String str)
5?
Checks if a String is not empty (""), not null and not whitespace only.
判断一个字W串是否非空Q空gI处? StringUtils.isNotBlank(null) = false StringUtils.isNotBlank("") = false StringUtils.isNotBlank(" ") = false StringUtils.isNotBlank("bob") = true StringUtils.isNotBlank(" bob ") = true
@param str the String to check, may be null
@return true if the String is
not empty and not null and not whitespace
@since 2.0
public static boolean isNotBlank(String str)
四?I格处理
6?
Removes control characters (char <= 32) from both
ends of this String, handling null by returning
null.
The String is trimmed using {@link String#trim()}.
Trim removes start and end characters <= 32.
To strip whitespace use {@link //strip(String)}.
To trim your choice of characters, use the
{@link //strip(String, String)} methods.
格式化一个字W串中的I格Q有非空判断处理Q?StringUtils.trim(null) = null StringUtils.trim("") = "" StringUtils.trim(" ") = "" StringUtils.trim("abc") = "abc" StringUtils.trim(" abc ") = "abc"
@param str the String to be trimmed, may be null
@return the trimmed string, null if null String input
public static String trim(String str)
7?
Removes control characters (char <= 32) from both
ends of this String returning null if the String is
empty ("") after the trim or if it is null.
The String is trimmed using {@link String#trim()}.
Trim removes start and end characters <= 32.
To strip whitespace use {@link /stripToNull(String)}.
格式化一个字W串中的I格Q有非空判断处理Q如果ؓI回nullQ?StringUtils.trimToNull(null) = null StringUtils.trimToNull("") = null StringUtils.trimToNull(" ") = null StringUtils.trimToNull("abc") = "abc" StringUtils.trimToNull(" abc ") = "abc"
@param str the String to be trimmed, may be null
@return the trimmed String,
null if only chars <= 32, empty or null String input
@since 2.0
public static String trimToNull(String str)
8?
Removes control characters (char <= 32) from both
ends of this String returning an empty String ("") if the String
is empty ("") after the trim or if it is null.
The String is trimmed using {@link String#trim()}.
Trim removes start and end characters <= 32.
To strip whitespace use {@link /stripToEmpty(String)}.
格式化一个字W串中的I格Q有非空判断处理Q如果ؓI?"Q?StringUtils.trimToEmpty(null) = "" StringUtils.trimToEmpty("") = "" StringUtils.trimToEmpty(" ") = "" StringUtils.trimToEmpty("abc") = "abc" StringUtils.trimToEmpty(" abc ") = "abc"
@param str the String to be trimmed, may be null
@return the trimmed String, or an empty String if null input
@since 2.0
public static String trimToEmpty(String str)
五?字符串比?
9?
Compares two Strings, returning true if they are equal.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case sensitive.
判断两个字符串是否相{，有非I处理?StringUtils.equals(null, null) = true StringUtils.equals(null, "abc") = false StringUtils.equals("abc", null) = false StringUtils.equals("abc", "abc") = true StringUtils.equals("abc", "ABC") = false
@param str1 the first String, may be null
@param str2 the second String, may be null
@return true if the Strings are equal, case sensitive, or
both null
@see java.lang.String#equals(Object)
public static boolean equals(String str1, String str2)
10?
Compares two Strings, returning true if they are equal ignoring
the case.
nulls are handled without exceptions. Two null
references are considered equal. Comparison is case insensitive.
判断两个字符串是否相{，有非I处理。忽略大写 StringUtils.equalsIgnoreCase(null, null) = true StringUtils.equalsIgnoreCase(null, "abc") = false StringUtils.equalsIgnoreCase("abc", null) = false StringUtils.equalsIgnoreCase("abc", "abc") = true StringUtils.equalsIgnoreCase("abc", "ABC") = true
@param str1 the first String, may be null
@param str2 the second String, may be null
@return true if the Strings are equal, case insensitive, or
both null
@see java.lang.String#equalsIgnoreCase(String)
public static boolean equalsIgnoreCase(String str1, String str2)
六?IndexOf 处理
11?
Finds the first index within a String, handling null.
This method uses {@link String#indexOf(String)}.
A null String will return -1.
q回要查扄字符串所在位|，有非I处?StringUtils.indexOf(null, *) = -1 StringUtils.indexOf(*, null) = -1 StringUtils.indexOf("", "") = 0 StringUtils.indexOf("aabaabaa", "a") = 0 StringUtils.indexOf("aabaabaa", "b") = 2 StringUtils.indexOf("aabaabaa", "ab") = 1 StringUtils.indexOf("aabaabaa", "") = 0
@param str the String to check, may be null
@param searchStr the String to find, may be null
@return the first index of the search String,
-1 if no match or null string input
@since 2.0
public static int indexOf(String str, String searchStr)
12?
Finds the first index within a String, handling null.
This method uses {@link String#indexOf(String, int)}.
A null String will return -1.
A negative start position is treated as zero.
An empty ("") search String always matches.
A start position greater than the string length only matches
an empty search String.
q回要由指定位置开始查扄字符串所在位|，有非I处?StringUtils.indexOf(null, *, *) = -1 StringUtils.indexOf(*, null, *) = -1 StringUtils.indexOf("", "", 0) = 0 StringUtils.indexOf("aabaabaa", "a", 0) = 0 StringUtils.indexOf("aabaabaa", "b", 0) = 2 StringUtils.indexOf("aabaabaa", "ab", 0) = 1 StringUtils.indexOf("aabaabaa", "b", 3) = 5 StringUtils.indexOf("aabaabaa", "b", 9) = -1 StringUtils.indexOf("aabaabaa", "b", -1) = 2 StringUtils.indexOf("aabaabaa", "", 2) = 2 StringUtils.indexOf("abc", "", 9) = 3
@param str the String to check, may be null
@param searchStr the String to find, may be null
@param startPos the start position, negative treated as zero
@return the first index of the search String,
-1 if no match or null string input
@since 2.0
public static int indexOf(String str, String searchStr, int startPos)
七?子字W串处理Q?
13?
Gets a substring from the specified String avoiding exceptions.
A negative start position can be used to start n
characters from the end of the String.
A null String will return null.
An empty ("") String will return "".
q回指定位置开始的字符串中的所有字W?StringUtils.substring(null, *) = null StringUtils.substring("", *) = "" StringUtils.substring("abc", 0) = "abc" StringUtils.substring("abc", 2) = "c" StringUtils.substring("abc", 4) = "" StringUtils.substring("abc", -2) = "bc" StringUtils.substring("abc", -4) = "abc"
@param str the String to get the substring from, may be null
@param start the position to start from, negative means
count back from the end of the String by this many characters
@return substring from start position, null if null String input
public static String substring(String str, int start)
14?
Gets a substring from the specified String avoiding exceptions.
A negative start position can be used to start/end n
characters from the end of the String.
The returned substring starts with the character in the start
position and ends before the end position. All postion counting is
zero-based -- i.e., to start at the beginning of the string use
start = 0. Negative start and end positions can be used to
specify offsets relative to the end of the String.
If start is not strictly to the left of end, ""
is returned.
q回由开始位|到l束位置之间的子字符?StringUtils.substring(null, *, *) = null StringUtils.substring("", * , *) = ""; StringUtils.substring("abc", 0, 2) = "ab" StringUtils.substring("abc", 2, 0) = "" StringUtils.substring("abc", 2, 4) = "c" StringUtils.substring("abc", 4, 6) = "" StringUtils.substring("abc", 2, 2) = "" StringUtils.substring("abc", -2, -1) = "b" StringUtils.substring("abc", -4, 2) = "ab"
@param str the String to get the substring from, may be null
@param start the position to start from, negative means
count back from the end of the String by this many characters
@param end the position to end at (exclusive), negative means
count back from the end of the String by this many characters
@return substring from start position to end positon,
null if null String input
public static String substring(String str, int start, int end)
15?SubStringAfter/SubStringBeforeQ前后子字符串处理：
Gets the substring before the first occurance of a separator.
The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
A null separator will return the input string.
q回指定字符串之前的所有字W?StringUtils.substringBefore(null, *) = null StringUtils.substringBefore("", *) = "" StringUtils.substringBefore("abc", "a") = "" StringUtils.substringBefore("abcba", "b") = "a" StringUtils.substringBefore("abc", "c") = "ab" StringUtils.substringBefore("abc", "d") = "abc" StringUtils.substringBefore("abc", "") = "" StringUtils.substringBefore("abc", null) = "abc"
@param str the String to get a substring from, may be null
@param separator the String to search for, may be null
@return the substring before the first occurance of the separator,
null if null String input
@since 2.0
public static String substringBefore(String str, String separator)
16?
Gets the substring after the first occurance of a separator.
The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
A null separator will return the empty string if the
input string is not null.
q回指定字符串之后的所有字W?StringUtils.substringAfter(null, *) = null StringUtils.substringAfter("", *) = "" StringUtils.substringAfter(*, null) = "" StringUtils.substringAfter("abc", "a") = "bc" StringUtils.substringAfter("abcba", "b") = "cba" StringUtils.substringAfter("abc", "c") = "" StringUtils.substringAfter("abc", "d") = "" StringUtils.substringAfter("abc", "") = "abc"
@param str the String to get a substring from, may be null
@param separator the String to search for, may be null
@return the substring after the first occurance of the separator,
null if null String input
@since 2.0
public static String substringAfter(String str, String separator)
17?
Gets the substring before the last occurance of a separator.
The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
An empty or null separator will return the input string.
q回最后一个指定字W串之前的所有字W?StringUtils.substringBeforeLast(null, *) = null StringUtils.substringBeforeLast("", *) = "" StringUtils.substringBeforeLast("abcba", "b") = "abc" StringUtils.substringBeforeLast("abc", "c") = "ab" StringUtils.substringBeforeLast("a", "a") = "" StringUtils.substringBeforeLast("a", "z") = "a" StringUtils.substringBeforeLast("a", null) = "a" StringUtils.substringBeforeLast("a", "") = "a"
@param str the String to get a substring from, may be null
@param separator the String to search for, may be null
@return the substring before the last occurance of the separator,
null if null String input
@since 2.0
public static String substringBeforeLast(String str, String separator)
18?
Gets the substring after the last occurance of a separator.
The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
An empty or null separator will return the empty string if
the input string is not null.
q回最后一个指定字W串之后的所有字W?StringUtils.substringAfterLast(null, *) = null StringUtils.substringAfterLast("", *) = "" StringUtils.substringAfterLast(*, "") = "" StringUtils.substringAfterLast(*, null) = "" StringUtils.substringAfterLast("abc", "a") = "bc" StringUtils.substringAfterLast("abcba", "b") = "a" StringUtils.substringAfterLast("abc", "c") = "" StringUtils.substringAfterLast("a", "a") = "" StringUtils.substringAfterLast("a", "z") = ""
@param str the String to get a substring from, may be null
@param separator the String to search for, may be null
@return the substring after the last occurance of the separator,
null if null String input
@since 2.0
public static String substringAfterLast(String str, String separator)
八?ReplacingQ字W串替换Q?
19?
Replaces all occurances of a String within another String.
A null reference passed to this method is a no-op.
以指定字W串替换原来字符串的的指定字W串 StringUtils.replace(null, *, *) = null StringUtils.replace("", *, *) = "" StringUtils.replace("aba", null, null) = "aba" StringUtils.replace("aba", null, null) = "aba" StringUtils.replace("aba", "a", null) = "aba" StringUtils.replace("aba", "a", "") = "aba" StringUtils.replace("aba", "a", "z") = "zbz"
@param text text to search and replace in, may be null
@param repl the String to search for, may be null
@param with the String to replace with, may be null
@return the text with any replacements processed,
null if null String input
@see #replace(String text, String repl, String with, int max)
public static String replace(String text, String repl, String with)
20?
Replaces a String with another String inside a larger String,
for the first max values of the search String.
A null reference passed to this method is a no-op.
以指定字W串最大替换原来字W串的的指定字符?StringUtils.replace(null, *, *, *) = null StringUtils.replace("", *, *, *) = "" StringUtils.replace("abaa", null, null, 1) = "abaa" StringUtils.replace("abaa", null, null, 1) = "abaa" StringUtils.replace("abaa", "a", null, 1) = "abaa" StringUtils.replace("abaa", "a", "", 1) = "abaa" StringUtils.replace("abaa", "a", "z", 0) = "abaa" StringUtils.replace("abaa", "a", "z", 1) = "zbaa" StringUtils.replace("abaa", "a", "z", 2) = "zbza" StringUtils.replace("abaa", "a", "z", -1) = "zbzz"
@param text text to search and replace in, may be null
@param repl the String to search for, may be null
@param with the String to replace with, may be null
@param max maximum number of values to replace, or -1 if no maximum
@return the text with any replacements processed,
null if null String input
public static String replace(String text, String repl, String with, int max)
九?Case conversionQ大写转换Q?
21?
Converts a String to upper case as per {@link String#toUpperCase()}.
A null input String returns null.
一个字W串变ؓ大写 StringUtils.upperCase(null) = null StringUtils.upperCase("") = "" StringUtils.upperCase("aBc") = "ABC"
@param str the String to upper case, may be null
@return the upper cased String, null if null String input
public static String upperCase(String str) 22?
Converts a String to lower case as per {@link String#toLowerCase()}.
A null input String returns null.
一个字W串转换为小?StringUtils.lowerCase(null) = null StringUtils.lowerCase("") = "" StringUtils.lowerCase("aBc") = "abc"
@param str the String to lower case, may be null
@return the lower cased String, null if null String input
public static String lowerCase(String str) 23?
Capitalizes a String changing the first letter to title case as
per {@link Character#toTitleCase(char)}. No other letters are changed.
For a word based alorithm, see {@link /WordUtils#capitalize(String)}.
A null input String returns null.
StringUtils.capitalize(null) = null StringUtils.capitalize("") = "" StringUtils.capitalize("cat") = "Cat" StringUtils.capitalize("cAt") = "CAt"
@param str the String to capitalize, may be null
@return the capitalized String, null if null String input
@see /WordUtils#capitalize(String)
@see /uncapitalize(String)
@since 2.0
字W串中的首字母大?
public static String capitalize(String str)
]]>