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

来源：blog.csdn.net/moshowgame/article/details/102914895

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        /        *        * NOTE: This method changed in Lang version 2.0.        * It no longer trims the CharSequence.        * That functionality is available in isBlank().
        *        * @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

 /        * Checks if none of the CharSequences are empty ("") or null.        *        *          * 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         * 
        *        * @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) {

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        /        * Checks if a CharSequence is whitespace, empty ("") or null.        * @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        /        * Checks if any one of the CharSequences are blank ("") or null and not whitespace only..        * @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        /        * Checks if none of the CharSequences are blank ("") or null and whitespace only..        * @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);}