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) {
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
