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decode
public static Integer decode(
String nm
)
throws
NumberFormatException
Decodes a String into an Integer.
Accepts decimal, hexadecimal, and octal numbers numbers given
by the following grammar:
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0x HexDigits
- Signopt
0X HexDigits
- Signopt
# HexDigits
- Signopt
0 OctalDigits
- Sign:
-
DecimalNumeral, HexDigits, and OctalDigits
are defined in §3.10.1
of the Java
Language Specification.
The sequence of characters following an (optional) negative
sign and/or radix specifier ("0x",
"0X", "#", or
leading zero) is parsed as by the Integer.parseInt
method with the indicated radix (10, 16, or 8). This sequence
of characters must represent a positive value or a NumberFormatException will be thrown. The result is negated
if first character of the specified String is the
minus sign. No whitespace characters are permitted in the
String.
getInteger
public static Integer getInteger(
String nm
)
Determines the integer value of the system property with the
specified name.
The first argument is treated as the name of a system property.
System properties are accessible through the
getProperty(java.lang.String) method. The
string value of this property is then interpreted as an integer
value and an Integer object representing this value is
returned. Details of possible numeric formats can be found with
the definition of getProperty.
If there is no property with the specified name, if the specified name
is empty or null, or if the property does not have
the correct numeric format, then null is returned.
In other words, this method returns an Integer
object equal to the value of:
getInteger(nm, null)
getInteger
public static Integer getInteger(
String nm,
int val
)
Determines the integer value of the system property with the
specified name.
The first argument is treated as the name of a system property.
System properties are accessible through the getProperty(java.lang.String) method. The
string value of this property is then interpreted as an integer
value and an Integer object representing this value is
returned. Details of possible numeric formats can be found with
the definition of getProperty.
The second argument is the default value. An Integer object
that represents the value of the second argument is returned if there
is no property of the specified name, if the property does not have
the correct numeric format, or if the specified name is empty or
null.
In other words, this method returns an Integer object
equal to the value of:
getInteger(nm, new Integer(val))
but in practice it may be implemented in a manner such as:
Integer result = getInteger(nm, null);
return (result == null) ? new Integer(val) : result;
to avoid the unnecessary allocation of an Integer
object when the default value is not needed.
getInteger
public static Integer getInteger(
String nm,
Integer val
)
Returns the integer value of the system property with the
specified name. The first argument is treated as the name of a
system property. System properties are accessible through the
getProperty(java.lang.String) method.
The string value of this property is then interpreted as an
integer value, as per the Integer.decode method,
and an Integer object representing this value is
returned.
- If the property value begins with the two ASCII characters
0x or the ASCII character #, not
followed by a minus sign, then the rest of it is parsed as a
hexadecimal integer exactly as by the method
valueOf(java.lang.String,int) with radix 16.
- If the property value begins with the ASCII character
0 followed by another character, it is parsed as an
octal integer exactly as by the method
valueOf(java.lang.String,int) with radix 8.
- Otherwise, the property value is parsed as a decimal integer
exactly as by the method valueOf(java.lang.String,int)
with radix 10.
The second argument is the default value. The default value is
returned if there is no property of the specified name, if the
property does not have the correct numeric format, or if the
specified name is empty or null.
parseInt
public static int parseInt(
String s
)
throws
NumberFormatException
Parses the string argument as a signed decimal integer. The
characters in the string must all be decimal digits, except that
the first character may be an ASCII minus sign '-'
('\u002D') to indicate a negative value. The resulting
integer value is returned, exactly as if the argument and the radix
10 were given as arguments to the
parseInt(java.lang.String,int) method.
parseInt
public static int parseInt(
String s,
int radix
)
throws
NumberFormatException
Parses the string argument as a signed integer in the radix
specified by the second argument. The characters in the string
must all be digits of the specified radix (as determined by
whether digit(char,int) returns a
nonnegative value), except that the first character may be an
ASCII minus sign '-' ('\u002D') to
indicate a negative value. The resulting integer value is returned.
An exception of type NumberFormatException is
thrown if any of the following situations occurs:
- The first argument is
null or is a string of
length zero.
- The radix is either smaller than
MIN_RADIX or
larger than MAX_RADIX.
- Any character of the string is not a digit of the specified
radix, except that the first character may be a minus sign
'-' ('\u002D') provided that the
string is longer than length 1.
- The value represented by the string is not a value of type
int.
Examples:
parseInt("0", 10) returns 0
parseInt("473", 10) returns 473
parseInt("-0", 10) returns 0
parseInt("-FF", 16) returns -255
parseInt("1100110", 2) returns 102
parseInt("2147483647", 10) returns 2147483647
parseInt("-2147483648", 10) returns -2147483648
parseInt("2147483648", 10) throws a NumberFormatException
parseInt("99", 8) throws a NumberFormatException
parseInt("Kona", 10) throws a NumberFormatException
parseInt("Kona", 27) returns 411787
toBinaryString
public static String toBinaryString(
int i
)
Returns a string representation of the integer argument as an
unsigned integer in base 2.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise it is equal to the
argument. This value is converted to a string of ASCII digits
in binary (base 2) with no extra leading 0s.
If the unsigned magnitude is zero, it is represented by a
single zero character '0'
('\u0030'); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The characters '0'
('\u0030') and '1'
('\u0031') are used as binary digits.
toHexString
public static String toHexString(
int i
)
Returns a string representation of the integer argument as an
unsigned integer in base 16.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise, it is equal to the
argument. This value is converted to a string of ASCII digits
in hexadecimal (base 16) with no extra leading
0s. If the unsigned magnitude is zero, it is
represented by a single zero character '0'
('\u0030'); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The following characters are used as
hexadecimal digits:
0123456789abcdef
These are the characters '\u0030' through
'\u0039' and '\u0061' through
'\u0066'. If uppercase letters are
desired, the toUpperCase() method may
be called on the result:
Integer.toHexString(n).toUpperCase()
toOctalString
public static String toOctalString(
int i
)
Returns a string representation of the integer argument as an
unsigned integer in base 8.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise, it is equal to the
argument. This value is converted to a string of ASCII digits
in octal (base 8) with no extra leading 0s.
If the unsigned magnitude is zero, it is represented by a
single zero character '0'
('\u0030'); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The following characters are used as octal
digits:
01234567
These are the characters '\u0030' through
'\u0037'.
toString
public static String toString(
int i
)
Returns a String object representing the
specified integer. The argument is converted to signed decimal
representation and returned as a string, exactly as if the
argument and radix 10 were given as arguments to the toString(int,int) method.
toString
public static String toString(
int i,
int radix
)
Returns a string representation of the first argument in the
radix specified by the second argument.
If the radix is smaller than Character.MIN_RADIX
or larger than Character.MAX_RADIX, then the radix
10 is used instead.
If the first argument is negative, the first element of the
result is the ASCII minus character '-'
('\u002D'). If the first argument is not
negative, no sign character appears in the result.
The remaining characters of the result represent the magnitude
of the first argument. If the magnitude is zero, it is
represented by a single zero character '0'
('\u0030'); otherwise, the first character of
the representation of the magnitude will not be the zero
character. The following ASCII characters are used as digits:
0123456789abcdefghijklmnopqrstuvwxyz
These are '\u0030' through
'\u0039' and '\u0061' through
'\u007A'. If radix is
N, then the first N of these characters
are used as radix-N digits in the order shown. Thus,
the digits for hexadecimal (radix 16) are
0123456789abcdef. If uppercase letters are
desired, the toUpperCase() method may
be called on the result:
Integer.toString(n, 16).toUpperCase()
valueOf
public static Integer valueOf(
String s
)
throws
NumberFormatException
Returns an Integer object holding the
value of the specified String. The argument is
interpreted as representing a signed decimal integer, exactly
as if the argument were given to the parseInt(java.lang.String) method. The result is an
Integer object that represents the integer value
specified by the string.
In other words, this method returns an Integer
object equal to the value of:
new Integer(Integer.parseInt(s))
valueOf
public static Integer valueOf(
String s,
int radix
)
throws
NumberFormatException
Returns an Integer object holding the value
extracted from the specified String when parsed
with the radix given by the second argument. The first argument
is interpreted as representing a signed integer in the radix
specified by the second argument, exactly as if the arguments
were given to the parseInt(java.lang.String,int)
method. The result is an Integer object that
represents the integer value specified by the string.
In other words, this method returns an Integer
object equal to the value of:
new Integer(Integer.parseInt(s, radix))
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