<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.7</version> </dependency>
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
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) {
https://mp.weixin.qq.com/s/hlSQbTRRzLNZvr_eu_lT_g