isEmpty 和 isBlank 的用法区别，居然一半的人答不上来.....

hi！我是沁禹～

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.
StringUtils: 官方文档

好了到这我们的教程也结束了😉
希望以上方法可以帮到您，祝您工作愉快！💖
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