类 StringUtils

字段详细资料

• SPACE

  public static final String SPACE

  A String for a space character.

  另请参阅:

  常量字段值

• EMPTY

  public static final String EMPTY

  The empty String "".

  另请参阅:

  常量字段值

方法详细资料

• isEmpty

  public static boolean isEmpty(CharSequence cs)

  Checks if a CharSequence is empty ("") or null.

   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().

  参数:

  cs - the CharSequence to check, may be null

  返回:

  true if the CharSequence is empty or null

• isBlank

  public static boolean isBlank(CharSequence cs)

  Checks if a CharSequence is empty (""), null or whitespace only.

  Whitespace is defined by Character.isWhitespace(char).

   StringUtils.isBlank(null)      = true
   StringUtils.isBlank("")        = true
   StringUtils.isBlank(" ")       = true
   StringUtils.isBlank("bob")     = false
   StringUtils.isBlank("  bob  ") = false
   

  参数:

  cs - the CharSequence to check, may be null

  返回:

  true if the CharSequence is null, empty or whitespace only

• isNotBlank

  public static boolean isNotBlank(CharSequence cs)

  Checks if a CharSequence is not empty (""), not null and not whitespace only.

  Whitespace is defined by Character.isWhitespace(char).

   StringUtils.isNotBlank(null)      = false
   StringUtils.isNotBlank("")        = false
   StringUtils.isNotBlank(" ")       = false
   StringUtils.isNotBlank("bob")     = true
   StringUtils.isNotBlank("  bob  ") = true
   

  参数:

  cs - the CharSequence to check, may be null

  返回:

  true if the CharSequence is not empty and not null and not whitespace only

  从以下版本开始:

  2.0, 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)

• equals

  public static boolean equals(CharSequence cs1,
                               CharSequence cs2)

  Compares two CharSequences, returning true if they represent equal sequences of characters.

  nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case sensitive.

   StringUtils.equals(null, null)   = true
   StringUtils.equals(null, "abc")  = false
   StringUtils.equals("abc", null)  = false
   StringUtils.equals("abc", "abc") = true
   StringUtils.equals("abc", "ABC") = false
   

  参数:

  cs1 - the first CharSequence, may be null

  cs2 - the second CharSequence, may be null

  返回:

  true if the CharSequences are equal (case-sensitive), or both null

  从以下版本开始:

  3.0 Changed signature from equals(String, String) to equals(CharSequence, CharSequence)

  另请参阅:

  Object.equals(Object)

• regionMatches

  public static boolean regionMatches(CharSequence cs,
                                      boolean ignoreCase,
                                      int thisStart,
                                      CharSequence substring,
                                      int start,
                                      int length)

  Green implementation of regionMatches.

  参数:

  cs - the CharSequence to be processed

  ignoreCase - whether or not to be case insensitive

  thisStart - the index to start on the cs CharSequence

  substring - the CharSequence to be looked for

  start - the index to start on the substring CharSequence

  length - character length of the region

  返回:

  whether the region matched

• isNumeric

  public static boolean isNumeric(CharSequence cs)

  Checks if the CharSequence contains only Unicode digits. A decimal point is not a Unicode digit and returns false.

  null will return false. An empty CharSequence (length()=0) will return false.

  Note that the method does not allow for a leading sign, either positive or negative. Also, if a String passes the numeric test, it may still generate a NumberFormatException when parsed by Integer.parseInt or Long.parseLong, e.g. if the value is outside the range for int or long respectively.

   StringUtils.isNumeric(null)   = false
   StringUtils.isNumeric("")     = false
   StringUtils.isNumeric("  ")   = false
   StringUtils.isNumeric("123")  = true
   StringUtils.isNumeric("१२३")  = true
   StringUtils.isNumeric("12 3") = false
   StringUtils.isNumeric("ab2c") = false
   StringUtils.isNumeric("12-3") = false
   StringUtils.isNumeric("12.3") = false
   StringUtils.isNumeric("-123") = false
   StringUtils.isNumeric("+123") = false
   

  参数:

  cs - the CharSequence to check, may be null

  返回:

  true if only contains digits, and is non-null

  从以下版本开始:

  3.0 Changed signature from isNumeric(String) to isNumeric(CharSequence), 3.0 Changed "" to return false and not true