--项目中的用法。
1、StringUtils.join
List dwVoListInTab = this.prodService.getPicTabVOList(picId);
List dwNameListInTab = new ArrayList();
for (PrdTabVO dwVo : dwVoListInTab) {
String dwName = this.prodService.cvtTabNo2DWName(useProdNo, picId,
dwVo.getCTabNo());
dwNameListInTab.add(dwName);
dwNameMap.put(dwVo.getCNmeEn(), dwName);
}
((List)plyDwNameList).addAll(dwNameListInTab);
String dwNameListStr = "['" + StringUtils.join(dwNameListInTab.toArray(), "','") + "']";
其它：
StringUtils.join(new String[]{"cat","dog","carrot","leaf","door"}, ":")
// cat:dog:carrot:leaf:door
2、StringUtils.isNotEmpty //Checks if a String is not empty ("") and not null.
if (StringUtils.isNotEmpty(onload))
onload = sub.replace(onload);
else {
onload = "";
}
public String replace(char oldChar,char newChar)返回一个新的字符串，它是通过用 newChar 替换此字符串中出现的所有 oldChar 得到的。
如果 oldChar 在此 String 对象表示的字符序列中没有出现，则返回对此 String 对象的引用。
3、StringUtils.equals //StringUtils.equals(null, null) = true
if (!StringUtils.equals(prodKindNo, "00")) {
}
4、StringUtils.isBlank //Checks if a String is whitespace, empty ("") or null.
if (StringUtils.isBlank(taskId))
jsBuffer.append("var taskId='';\n");
else {
jsBuffer.append("var taskId='" + taskId + "';\n");
}
5、StringUtils.leftPad(String str, int size,String padStr) --左填充
//投保年度【保险起期 - 初登年月】 单位：年
String ply_year = StringUtils.leftPad(String.valueOf(DateUtils.compareYear(regDate,base.getTInsrncBgnTm())), 2, '0');
/**
4260 * <p>Left pad a String with a specified String.</p>
4261 *
4262 * <p>Pad to a size of <code>size</code>.</p>
4263 *
4264 * <pre>
4265 * StringUtils.leftPad(null, *, *) = null
4266 * StringUtils.leftPad("", 3, "z") = "zzz"
4267 * StringUtils.leftPad("bat", 3, "yz") = "bat"
4268 * StringUtils.leftPad("bat", 5, "yz") = "yzbat"
4269 * StringUtils.leftPad("bat", 8, "yz") = "yzyzybat"
4270 * StringUtils.leftPad("bat", 1, "yz") = "bat"
4271 * StringUtils.leftPad("bat", -1, "yz") = "bat"
4272 * StringUtils.leftPad("bat", 5, null) = " bat"
4273 * StringUtils.leftPad("bat", 5, "") = " bat"
4274 * </pre>
4275 *
4276 * @param str the String to pad out, may be null
4277 * @param size the size to pad to
4278 * @param padStr the String to pad with, null or empty treated as single space
4279 * @return left padded String or original String if no padding is necessary,
4280 * <code>null</code> if null String input
4281 */
4282 public static String leftPad(String str, int size, String padStr) {
4283 if (str == null) {
4284 return null;
4285 }
4286 if (isEmpty(padStr)) {
4287 padStr = " ";
4288 }
4289 int padLen = padStr.length();
4290 int strLen = str.length();
4291 int pads = size - strLen;
4292 if (pads <= 0) {
4293 return str; // returns original String when possible
4294 }
4295 if (padLen == 1 && pads <= PAD_LIMIT) {
4296 return leftPad(str, size, padStr.charAt(0));
4297 }
4298
4299 if (pads == padLen) {
4300 return padStr.concat(str);
4301 } else if (pads < padLen) {
4302 return padStr.substring(0, pads).concat(str);
4303 } else {
4304 char[] padding = new char[pads];
4305 char[] padChars = padStr.toCharArray();
4306 for (int i = 0; i < pads; i++) {
4307 padding[i] = padChars[i % padLen];
4308 }
4309 return new String(padding).concat(str);
4310 }
4311 }
---------------------------------------------
详见：http://commons.apache.org/lang/api/org/apache/commons/lang/StringUtils.html
isEmpty
public static boolean isEmpty(CharSequence str)
Checks if a String is empty ("") or null.
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().
Parameters:
str - the String to check, may be null
Returns:
true if the String is empty or null
isNotEmpty
public static boolean isNotEmpty(CharSequence str)
Checks if a String is not empty ("") and not null.
StringUtils.isNotEmpty(null) = false
StringUtils.isNotEmpty("") = false
StringUtils.isNotEmpty(" ") = true
StringUtils.isNotEmpty("bob") = true
StringUtils.isNotEmpty(" bob ") = true
Parameters:
str - the String to check, may be null
Returns:
true if the String is not empty and not null
isBlank
public static boolean isBlank(CharSequence str)
Checks if a String is whitespace, empty ("") or null.
StringUtils.isBlank(null) = true
StringUtils.isBlank("") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank("bob") = false
StringUtils.isBlank(" bob ") = false
Parameters:
str - the String to check, may be null
Returns:
true if the String is null, empty or whitespace
Since:
2.0
isNotBlank
public static boolean isNotBlank(CharSequence str)
Checks if a String is not empty (""), not null and not whitespace only.
StringUtils.isNotBlank(null) = false
StringUtils.isNotBlank("") = false
StringUtils.isNotBlank(" ") = false
StringUtils.isNotBlank("bob") = true
StringUtils.isNotBlank(" bob ") = true
Parameters:
str - the String to check, may be null
Returns:
true if the String is not empty and not null and not whitespace
Since:
2.0
trim
public static String trim(String str)
Removes control characters (char <= 32) from both ends of this String, handling null by
returning null.
The String is trimmed using String.trim(). Trim removes start and end characters <= 32.
To strip whitespace use strip(String).
To trim your choice of characters, use the strip(String, String) methods.
StringUtils.trim(null) = null
StringUtils.trim("") = ""
StringUtils.trim(" ") = ""
StringUtils.trim("abc") = "abc"
StringUtils.trim(" abc ") = "abc"
Parameters:
str - the String to be trimmed, may be null
Returns:
the trimmed string, null if null String input
trimToNull
public static String trimToNull(String str)
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 String.trim(). Trim removes start and end characters <= 32.
To strip whitespace use stripToNull(String).
StringUtils.trimToNull(null) = null
StringUtils.trimToNull("") = null
StringUtils.trimToNull(" ") = null
StringUtils.trimToNull("abc") = "abc"
StringUtils.trimToNull(" abc ") = "abc"
Parameters:
str - the String to be trimmed, may be null
Returns:
the trimmed String, null if only chars <= 32, empty or null String input
Since:
2.0
trimToEmpty
public static String trimToEmpty(String str)
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 String.trim(). Trim removes start and end characters <= 32.
To strip whitespace use stripToEmpty(String).
StringUtils.trimToEmpty(null) = ""
StringUtils.trimToEmpty("") = ""
StringUtils.trimToEmpty(" ") = ""
StringUtils.trimToEmpty("abc") = "abc"
StringUtils.trimToEmpty(" abc ") = "abc"
Parameters:
str - the String to be trimmed, may be null
Returns:
the trimmed String, or an empty String if null input
Since:
2.0
equals
public static boolean equals(String str1,
String str2)
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.
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
Parameters:
str1 - the first String, may be null
str2 - the second String, may be null
Returns:
true if the Strings are equal, case sensitive, or both null
See Also:
String.equals(Object)
startsWith
public static boolean startsWith(String str,
String prefix)
Check if a String starts with a specified prefix.
nulls are handled without exceptions. Two null references are considered to be equal. The
comparison is case sensitive.
StringUtils.startsWith(null, null) = true
StringUtils.startsWith(null, "abc") = false
StringUtils.startsWith("abcdef", null) = false
StringUtils.startsWith("abcdef", "abc") = true
StringUtils.startsWith("ABCDEF", "abc") = false
Parameters:
str - the String to check, may be null
prefix - the prefix to find, may be null
Returns:
true if the String starts with the prefix, case sensitive, or both null
Since:
2.4
See Also:
String.startsWith(String)
1.去除尾部换行符，使用函数：StringUtils.chomp(testString)
函数介绍:去除testString尾部的换行符
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
2.判断字符串内容的类型，函数介绍：
StringUtils.isNumeric( testString ) :如果testString全由数字组成返回True
StringUtils.isAlpha( testString ) :如果testString全由字母组成返回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
3.查找嵌套字符串，使用函数：
StringUtils.substringBetween(testString,header,tail)
函数介绍：在testString中取得header和tail之间的字符串。不存在则返回空
例程：
String htmlContent = "ABC1234ABC4567";
System.out.println(StringUtils.substringBetween(htmlContent, "1234", "4567"));
System.out.println(StringUtils.substringBetween(htmlContent, "12345", "4567"));
输出如下：
ABC
null
4.颠倒字符串，使用函数：StringUtils.reverse(testString)
函数介绍:得到testString中字符颠倒后的字符串
例程:
System.out.println( StringUtils.reverse("ABCDE"));
输出如下:
EDCBA
5.部分截取字符串，使用函数：
StringUtils.substringBetween(testString,fromString,toString ):取得两字符之间的字符串
StringUtils.substringAfter( ):取得指定字符串后的字符串
StringUtils.substringBefore( )：取得指定字符串之前的字符串
StringUtils.substringBeforeLast( )：取得最后一个指定字符串之前的字符串
StringUtils.substringAfterLast( )：取得最后一个指定字符串之后的字符串
函数介绍：上面应该都讲明白了吧。
例程：
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：
N0: 25 , N1: 30, N2: 40, N3: 50, N4: 40) [50,60, N5: 30