Isempty and isblank

isEmpty

// Empty checks
    //-----------------------------------------------------------------------
    /** * <p>Checks if a CharSequence is empty ("") or null.</p> * * <pre> * StringUtils.isEmpty(null) = true * StringUtils.isEmpty("") = true * StringUtils.isEmpty(" ") = false * StringUtils.isEmpty("bob") = false * StringUtils.isEmpty(" bob ") = false * </pre> * * <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;
    }

isBlank

/** * <p>Checks if a CharSequence is empty (""), null or whitespace only.</p> * * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p> * * <pre> * StringUtils.isBlank(null) = true * StringUtils.isBlank("") = true * StringUtils.isBlank(" ") = true * StringUtils.isBlank("bob") = false * StringUtils.isBlank(" bob ") = false * </pre> * * @param cs the CharSequence to check, may be null * @return {@code true} if the CharSequence is null, empty or whitespace only * @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))) {
    
                return false;
            }
        }
        return true;
    }

We can know from the source code ,isEmpty Judge whether it is empty and length ,isBlank It also determines whether it is a space .