StringUtils中isEmpty 和 isBlank 的用法区别

怼烎@ 2024-02-21 09:26 22阅读 0赞

## isEmpty 和 isBlank 的用法区别 ##

### 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

#### 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.

这个方法接收的是一个变长参数，就是说你可以传入多个。

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() ####

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

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);
 }