## org.apache.hadoop.util
Class StringUtils

    java.lang.Object
      org.apache.hadoop.util.StringUtils

    public class StringUtils

extends Object

General string utils

Nested Class Summary
`static class` `StringUtils.TraditionalBinaryPrefix` The traditional binary prefixes, kilo, mega, ..., exa, which can be represented by a 64-bit integer.

Field Summary
`static char` `COMMA`
`static String` `COMMA_STR`
`static char` `ESCAPE_CHAR`

Constructor Summary
`StringUtils()`

Method Summary
`static String` `arrayToString(String[] strs)` Given an array of strings, return a comma-separated list of its elements.
`static String` `byteDesc(long len)` Return an abbreviated English-language desc of the byte length
`static String` `byteToHexString(byte[] bytes)` Same as byteToHexString(bytes, 0, bytes.length).
`static String` `byteToHexString(byte[] bytes, int start, int end)` Given an array of bytes it will convert the bytes to a hex string representation of the bytes
`static String` `camelize(String s)` Convert SOME_STUFF to SomeStuff
`static String` `capitalize(String s)` Capitalize a word
`static String` `escapeHTML(String string)` Escapes HTML Special characters present in the string.
`static String` `escapeString(String str)` Escape commas in the string using the default escape char
`static String` `escapeString(String str, char escapeChar, char charToEscape)` Escape `charToEscape` in the string with the escape char `escapeChar`
`static String` `escapeString(String str, char escapeChar, char[] charsToEscape)`
`static int` `findNext(String str, char separator, char escapeChar, int start, StringBuilder split)` Finds the first occurrence of the separator character ignoring the escaped separators starting from the index.
`static String` `formatPercent(double done, int digits)` Format a percentage for presentation to the user.
`static String` `formatTime(long timeDiff)` Given the time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec.
`static String` `formatTimeDiff(long finishTime, long startTime)` Given a finish and start time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec, for the time difference between two times.
`static String` `getFormattedTimeWithDiff(DateFormat dateFormat, long finishTime, long startTime)` Formats time in ms and appends difference (finishTime - startTime) as returned by formatTimeDiff().
`static String` `getHostname()` Return hostname without throwing exception.
`static Collection<String>` `getStringCollection(String str)` Returns a collection of strings.
`static String[]` `getStrings(String str)` Returns an arraylist of strings.
`static byte[]` `hexStringToByte(String hex)` Given a hexstring this will return the byte array corresponding to the string
`static String` `humanReadableInt(long number)` Given an integer, return a string that is in an approximate, but human readable format.
`static String` `join(CharSequence separator, Iterable<String> strings)` Concatenates strings, using a separator.
`static String` `join(CharSequence separator, String[] strings)` Concatenates strings, using a separator.
`static String` `limitDecimalTo2(double d)`
`static String` `simpleHostname(String fullHostname)` Given a full hostname, return the word upto the first dot.
`static String[]` `split(String str)` Split a string using the default separator
`static String[]` `split(String str, char escapeChar, char separator)` Split a string using the given separator
`static void` `startupShutdownMessage(Class<?> clazz, String[] args, org.apache.commons.logging.Log LOG)` Print a log message for starting up and shutting down
`static String` `stringifyException(Throwable e)` Make a string representation of the exception.
`static Path[]` `stringToPath(String[] str)`
`static URI[]` `stringToURI(String[] str)`
`static String` `unEscapeString(String str)` Unescape commas in the string using the default escape char
`static String` `unEscapeString(String str, char escapeChar, char charToEscape)` Unescape `charToEscape` in the string with the escape char `escapeChar`
`static String` `unEscapeString(String str, char escapeChar, char[] charsToEscape)`
`static String` `uriToString(URI[] uris)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### COMMA

    public static final char COMMA

See Also:
  Constant Field Values

### COMMA_STR

    public static final String COMMA_STR

See Also:
  Constant Field Values

### ESCAPE_CHAR

    public static final char ESCAPE_CHAR

See Also:
  Constant Field Values

Constructor Detail

### StringUtils

    public StringUtils()

Method Detail

### stringifyException

    public static String stringifyException(Throwable e)

  Make a string representation of the exception.

  Parameters:
    `e` - The exception to stringify
  Returns:
    A string with exception name and call stack.

### simpleHostname

    public static String simpleHostname(String fullHostname)

  Given a full hostname, return the word upto the first dot.

  Parameters:
    `fullHostname` - the full hostname
  Returns:
    the hostname to the first dot

### humanReadableInt

    public static String humanReadableInt(long number)

  Given an integer, return a string that is in an approximate, but human readable format. It uses the bases 'k', 'm', and 'g' for 1024, 1024**2, and 1024**3.

  Parameters:
    `number` - the number to format
  Returns:
    a human readable form of the integer

### formatPercent

    public static String formatPercent(double done,
                                       int digits)

  Format a percentage for presentation to the user.

  Parameters:
    `done` - the percentage to format (0.0 to 1.0)
    `digits` - the number of digits past the decimal point
  Returns:
    a string representation of the percentage

### arrayToString

    public static String arrayToString(String[] strs)

  Given an array of strings, return a comma-separated list of its elements.

  Parameters:
    `strs` - Array of strings
  Returns:
    Empty string if strs.length is 0, comma separated list of strings otherwise

### byteToHexString

    public static String byteToHexString(byte[] bytes,
                                         int start,
                                         int end)

  Given an array of bytes it will convert the bytes to a hex string representation of the bytes

  Parameters:
    `bytes` -
    `start` - start index, inclusively
    `end` - end index, exclusively
  Returns:
    hex string representation of the byte array

### byteToHexString

    public static String byteToHexString(byte[] bytes)

  Same as byteToHexString(bytes, 0, bytes.length).

### hexStringToByte

    public static byte[] hexStringToByte(String hex)

  Given a hexstring this will return the byte array corresponding to the string

  Parameters:
    `hex` - the hex String array
  Returns:
    a byte array that is a hex string representation of the given string. The size of the byte array is therefore hex.length/2

### uriToString

    public static String uriToString(URI[] uris)

  Parameters:
    `uris` -

### stringToURI

    public static URI[] stringToURI(String[] str)

  Parameters:
    `str` -

### stringToPath

    public static Path[] stringToPath(String[] str)

  Parameters:
    `str` -

### formatTimeDiff

    public static String formatTimeDiff(long finishTime,
                                        long startTime)

  Given a finish and start time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec, for the time difference between two times. If finish time comes before start time then negative valeus of X, Y and Z wil return.

  Parameters:
    `finishTime` - finish time
    `startTime` - start time

### formatTime

    public static String formatTime(long timeDiff)

  Given the time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec.

  Parameters:
    `timeDiff` - The time difference to format

### getFormattedTimeWithDiff

    public static String getFormattedTimeWithDiff(DateFormat dateFormat,
                                                  long finishTime,
                                                  long startTime)

  Formats time in ms and appends difference (finishTime - startTime) as returned by formatTimeDiff(). If finish time is 0, empty string is returned, if start time is 0 then difference is not appended to return value.

  Parameters:
    `dateFormat` - date format to use
    `finishTime` - fnish time
    `startTime` - start time
  Returns:
    formatted value.

### getStrings

    public static String[] getStrings(String str)

  Returns an arraylist of strings.

  Parameters:
    `str` - the comma seperated string values
  Returns:
    the arraylist of the comma seperated string values

### getStringCollection

    public static Collection<String> getStringCollection(String str)

  Returns a collection of strings.

  Parameters:
    `str` - comma seperated string values
  Returns:
    an `ArrayList` of string values

### split

    public static String[] split(String str)

  Split a string using the default separator

  Parameters:
    `str` - a string that may have escaped separator
  Returns:
    an array of strings

### split

    public static String[] split(String str,
                                 char escapeChar,
                                 char separator)

  Split a string using the given separator

  Parameters:
    `str` - a string that may have escaped separator
    `escapeChar` - a char that be used to escape the separator
    `separator` - a separator char
  Returns:
    an array of strings

### findNext

    public static int findNext(String str,
                               char separator,
                               char escapeChar,
                               int start,
                               StringBuilder split)

  Finds the first occurrence of the separator character ignoring the escaped separators starting from the index. Note the substring between the index and the position of the separator is passed.

  Parameters:
    `str` - the source string
    `separator` - the character to find
    `escapeChar` - character used to escape
    `start` - from where to search
    `split` - used to pass back the extracted string

### escapeString

    public static String escapeString(String str)

  Escape commas in the string using the default escape char

  Parameters:
    `str` - a string
  Returns:
    an escaped string

### escapeString

    public static String escapeString(String str,
                                      char escapeChar,
                                      char charToEscape)

  Escape `charToEscape` in the string with the escape char `escapeChar`

  Parameters:
    `str` - string
    `escapeChar` - escape char
    `charToEscape` - the char to be escaped
  Returns:
    an escaped string

### escapeString

    public static String escapeString(String str,
                                      char escapeChar,
                                      char[] charsToEscape)

  Parameters:
    `charsToEscape` - array of characters to be escaped

### unEscapeString

    public static String unEscapeString(String str)

  Unescape commas in the string using the default escape char

  Parameters:
    `str` - a string
  Returns:
    an unescaped string

### unEscapeString

    public static String unEscapeString(String str,
                                        char escapeChar,
                                        char charToEscape)

  Unescape `charToEscape` in the string with the escape char `escapeChar`

  Parameters:
    `str` - string
    `escapeChar` - escape char
    `charToEscape` - the escaped char
  Returns:
    an unescaped string

### unEscapeString

    public static String unEscapeString(String str,
                                        char escapeChar,
                                        char[] charsToEscape)

  Parameters:
    `charsToEscape` - array of characters to unescape

### getHostname

    public static String getHostname()

  Return hostname without throwing exception.

  Returns:
    hostname

### startupShutdownMessage

    public static void startupShutdownMessage(Class<?> clazz,
                                              String[] args,
                                              org.apache.commons.logging.Log LOG)

  Print a log message for starting up and shutting down

  Parameters:
    `clazz` - the class of the server
    `args` - arguments
    `LOG` - the target log object

### escapeHTML

    public static String escapeHTML(String string)

  Escapes HTML Special characters present in the string.

  Parameters:
    `string` -
  Returns:
    HTML Escaped String representation

### byteDesc

    public static String byteDesc(long len)

  Return an abbreviated English-language desc of the byte length

### limitDecimalTo2

    public static String limitDecimalTo2(double d)

### join

    public static String join(CharSequence separator,
                              Iterable<String> strings)

  Concatenates strings, using a separator.

  Parameters:
    `separator` - Separator to join with.
    `strings` - Strings to join.
  Returns:
    the joined string

### join

    public static String join(CharSequence separator,
                              String[] strings)

  Concatenates strings, using a separator.

  Parameters:
    `separator` - to join with
    `strings` - to join
  Returns:
    the joined string

### capitalize

    public static String capitalize(String s)

  Capitalize a word

  Parameters:
    `s` - the input string
  Returns:
    capitalized string

### camelize

    public static String camelize(String s)

  Convert SOME_STUFF to SomeStuff

  Parameters:
    `s` - input string
  Returns:
    camelized string

Copyright © 2009 The Apache Software Foundation