The java.lang.Integer class of common Java APIs (with analysis and examples) _03

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As can be seen from the class definition, the Integer class inherits from the java.lang.Number class and implements the Comparable<Integer> interface.

public final class Integer extends Number implements Comparable<Integer>//源码

The Integer class wraps a value of the primitive type int in an object.

-------------------------------------------------- --static field---------------------------------------------- ---------

Static domain (directly called via Integer.xxx)

static int MAX_VALUE	A constant whose value is 231-1, which represents the maximum value that the int type can represent.
static int MIN_VALUE	A constant whose value is -231, which represents the smallest value that the int type can represent.
static int SIZE	Represents the number of bits in an int value.
static Class<Integer> TYPE	Represents a Class instance of the primitive type int.

-------------------------------------------------- Construction method------------------------------------------------ ------

Integer n = new Integer(xxx)

Integer(int value)	Constructs a newly allocated Integer object that represents the specified int value.
Integer(String s)	Constructs a newly allocated Integer object that represents the int value indicated by the String parameter. Can be used where strings smaller than 32 bits are to be converted to numbers.

Integer strNum = new Integer("32") and Inter intNum = new Integer(32) are equal.

-------------------------------------------------- static method ------------------------------------------------ -----

Static methods (directly called via Integer.xxx())

static int parseInt(String s)	Parse a string as a signed decimal integer. 例：Integer.parseInt（“-444”） = -444
static int parseInt(String s, int radix)	Parses a string in radix base as a signed decimal integer. 例：Integer.parseInt("111", 2 ) = 7
static String toBinaryString(int i)	Returns the string representation of the I integer arguments as a binary unsigned integer. ： ： Nteger.toBinaryString (8) = 1110
static String toHexString(int i)	Returns the string representation of an integer argument as a hexadecimal unsigned integer. Example: Integer.toHexString (255) = ff
static String toOctalString(int i)	Returns the string representation of an integer argument as an octal unsigned integer. 例：Integer.toOctalString(15) = 17
static String toString(int i)	返回整数 i 的String 形式。 例：Integer.toString（23） = “23”
static String toString(int i, int radix)	返回用radix进制表示的整数 i 的字符串形式。 例：Integer.toString（23, 8） = 27

---------------------------------------------------------对象方法----------------------------------------------

对象方法（需先调用构造函数构造具体对象后，用对象调用）

int    hashCode()	返回此 Integer 的哈希码。 例：new Integer( 55 ).hashCode() = 55
int intValue()	以 int 类型返回该 Integer 的值。 例：new Integer（55）.intValue = 55
String toString()	返回一个表示该 Integer 值的 String 对象。 例：new Integer(60).toString = "60"