StringUtils.isEmpty()和StringUtils.isB的区别
Moshow郑锴 人气:2也许你两个都不知道,也许你除了isEmpty/isNotEmpty/isNotBlank/isBlank外,并不知道还有isAnyEmpty/isNoneEmpty/isAnyBlank/isNoneBlank的存在, come on ,让我们一起来探索org.apache.commons.lang3.StringUtils;这个工具类.
#isEmpty系列
StringUtils.isEmpty()
>>>是否为空. 可以看到 " " 空格是会绕过这种空判断,因为是一个空格,并不是严格的空值,会导致 isEmpty(" ")=false
StringUtils.isEmpty(null) = true StringUtils.isEmpty("") = true StringUtils.isEmpty(" ") = false StringUtils.isEmpty(“bob”) = false StringUtils.isEmpty(" bob ") = false
/** * * <p>NOTE: This method changed in Lang version 2.0. * It no longer trims the CharSequence. * That functionality is available in isBlank().</p> * * @param cs the CharSequence to check, may be null * @return {@code true} if the CharSequence is empty or null * @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence) */ public static boolean isEmpty(final CharSequence cs) { return cs == null || cs.length() == 0; }
StringUtils.isNotEmpty()
>>>相当于不为空 , = !isEmpty()
public static boolean isNotEmpty(final CharSequence cs) { return !isEmpty(cs); }
StringUtils.isAnyEmpty()
>>>是否有一个为空,只有一个为空,就为true.
StringUtils.isAnyEmpty(null) = true StringUtils.isAnyEmpty(null, “foo”) = true StringUtils.isAnyEmpty("", “bar”) = true StringUtils.isAnyEmpty(“bob”, “”) = true StringUtils.isAnyEmpty(" bob ", null) = true StringUtils.isAnyEmpty(" ", “bar”) = false StringUtils.isAnyEmpty(“foo”, “bar”) = false
/** * @param css the CharSequences to check, may be null or empty * @return {@code true} if any of the CharSequences are empty or null * @since 3.2 */ public static boolean isAnyEmpty(final CharSequence... css) { if (ArrayUtils.isEmpty(css)) { return true; } for (final CharSequence cs : css){ if (isEmpty(cs)) { return true; } } return false; }
StringUtils.isNoneEmpty()
>>>相当于!isAnyEmpty(css) , 必须所有的值都不为空才返回true
/** * <p>Checks if none of the CharSequences are empty ("") or null.</p> * * <pre> * StringUtils.isNoneEmpty(null) = false * StringUtils.isNoneEmpty(null, "foo") = false * StringUtils.isNoneEmpty("", "bar") = false * StringUtils.isNoneEmpty("bob", "") = false * StringUtils.isNoneEmpty(" bob ", null) = false * StringUtils.isNoneEmpty(" ", "bar") = true * StringUtils.isNoneEmpty("foo", "bar") = true * </pre> * * @param css the CharSequences to check, may be null or empty * @return {@code true} if none of the CharSequences are empty or null * @since 3.2 */ public static boolean isNoneEmpty(final CharSequence... css) { return !isAnyEmpty(css); }
#isBank系列
StringUtils.isBlank()
>>> 是否为真空值(空格或者空值)
StringUtils.isBlank(null) = true StringUtils.isBlank("") = true StringUtils.isBlank(" ") = true StringUtils.isBlank(“bob”) = false StringUtils.isBlank(" bob ") = false
/** * <p>Checks if a CharSequence is whitespace, empty ("") or null.</p> * @param cs the CharSequence to check, may be null * @return {@code true} if the CharSequence is null, empty or whitespace * @since 2.0 * @since 3.0 Changed signature from isBlank(String) to isBlank(CharSequence) */ public static boolean isBlank(final CharSequence cs) { int strLen; if (cs == null || (strLen = cs.length()) == 0) { return true; } for (int i = 0; i < strLen; i++) { if (Character.isWhitespace(cs.charAt(i)) == false) { return false; } } return true; }
StringUtils.isNotBlank()
>>> 是否真的不为空,不是空格或者空值 ,相当于!isBlank();
public static boolean isNotBlank(final CharSequence cs) { return !isBlank(cs); }
StringUtils.isAnyBlank()
>>>是否包含任何真空值(包含空格或空值)
StringUtils.isAnyBlank(null) = true StringUtils.isAnyBlank(null, “foo”) = true StringUtils.isAnyBlank(null, null) = true StringUtils.isAnyBlank("", “bar”) = true StringUtils.isAnyBlank(“bob”, “”) = true StringUtils.isAnyBlank(" bob ", null) = true StringUtils.isAnyBlank(" ", “bar”) = true StringUtils.isAnyBlank(“foo”, “bar”) = false
/** * <p>Checks if any one of the CharSequences are blank ("") or null and not whitespace only..</p> * @param css the CharSequences to check, may be null or empty * @return {@code true} if any of the CharSequences are blank or null or whitespace only * @since 3.2 */ public static boolean isAnyBlank(final CharSequence... css) { if (ArrayUtils.isEmpty(css)) { return true; } for (final CharSequence cs : css){ if (isBlank(cs)) { return true; } } return false; }
StringUtils.isNoneBlank()
>>>是否全部都不包含空值或空格
StringUtils.isNoneBlank(null) = false StringUtils.isNoneBlank(null, “foo”) = false StringUtils.isNoneBlank(null, null) = false StringUtils.isNoneBlank("", “bar”) = false StringUtils.isNoneBlank(“bob”, “”) = false StringUtils.isNoneBlank(" bob ", null) = false StringUtils.isNoneBlank(" ", “bar”) = false StringUtils.isNoneBlank(“foo”, “bar”) = true
/** * <p>Checks if none of the CharSequences are blank ("") or null and whitespace only..</p> * @param css the CharSequences to check, may be null or empty * @return {@code true} if none of the CharSequences are blank or null or whitespace only * @since 3.2 */ public static boolean isNoneBlank(final CharSequence... css) { return !isAnyBlank(css); }
StringUtils的其他方法
可以参考官方的文档,里面有详细的描述,有些方法还是很好用的.
https://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/StringUtils.html
方法名 | 英文解释 | 中文解释 |
---|---|---|
IsEmpty/IsBlank | checks if a String contains text | 检查字符串是否包含文本 |
Trim/Strip | removes leading and trailing whitespace | 删除前导和尾随空格 |
Equals/Compare | compares two strings null-safe | 比较两个字符串是否为null安全的 |
startsWith | check if a String starts with a prefix null-safe | 检查字符串是否以前缀null安全开头 |
endsWith | check if a String ends with a suffix null-safe | 检查字符串是否以后缀null安全结尾 |
IndexOf/LastIndexOf/Contains | null-safe index-of checks | 包含空安全索引检查 |
IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut | index-of any of a set of Strings | 任意一组字符串的索引 |
ContainsOnly/ContainsNone/ContainsAny | does String contains only/none/any of these characters | 字符串是否仅包含/无/这些字符中的任何一个 |
Substring/Left/Right/Mid | null-safe substring extractions | 字符串安全提取 |
SubstringBefore/SubstringAfter/SubstringBetween | substring extraction relative to other strings -相对其他字符串的字符串提取 | |
Split/Join | splits a String into an array of substrings and vice versa | 将字符串拆分为子字符串数组,反之亦然 |
Remove/Delete | removes part of a String -删除字符串的一部分 | |
Replace/Overlay | Searches a String and replaces one String with another | 搜索字符串,然后用另一个字符串替换 |
Chomp/Chop | removes the last part of a String | 删除字符串的最后一部分 |
AppendIfMissing | appends a suffix to the end of the String if not present | 如果不存在后缀,则在字符串的末尾附加一个后缀 |
PrependIfMissing | prepends a prefix to the start of the String if not present | 如果不存在前缀,则在字符串的开头添加前缀 |
LeftPad/RightPad/Center/Repeat | pads a String | 填充字符串 |
UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize | changes the case of a String | 更改字符串的大小写 |
CountMatches | counts the number of occurrences of one String in another | 计算一个字符串在另一个字符串中出现的次数 |
IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable | checks the characters in a String | 检查字符串中的字符 |
DefaultString | protects against a null input String | 防止输入字符串为空 |
Rotate | rotate (circular shift) a String | 旋转(循环移位)字符串 |
Reverse/ReverseDelimited | reverses a String -反转字符串 | |
Abbreviate | abbreviates a string using ellipsis or another given String | 使用省略号或另一个给定的String缩写一个字符串 |
Difference | compares Strings and reports on their differences | 比较字符串并报告其差异 |
LevenshteinDistance | the number of changes needed to change one String into another | 将一个String转换为另一个String所需的更改次数 |
以上为个人经验,希望能给大家一个参考,也希望大家多多支持。
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