Java 简明教程
Java - Integer class
Introduction
Java Integer 类将基本类型 int 的一个值封装到一个对象中。类型为 Integer 的一个对象包含一个字段，其类型为 int。
The Java Integer class wraps a value of primitive type int in an object. An object of type Integer contains a single field whose type is int.
Class Declaration
以下是 java.lang.Integer 的声明 −
Following is the declaration for java.lang.Integer class −
public final class Integer
extends Number
implements Comparable<Integer>Field
以下是 java.lang.Integer 类字段 −
Following are the fields for java.lang.Integer class −
-
static int MAX_VALUE − This is a constant holding the maximum value an int can have, 231-1.
-
static int MIN_VALUE − This is a constant holding the minimum value an int can have, -231.
-
static int SIZE − This is the number of bits used to represent an int value in two’s complement binary form.
-
static Class<Integer> TYPE − This is the class instance representing the primitive type int.
Methods inherited
此类从以下类中继承方法：
This class inherits methods from the following classes −
-
java.lang.Object
Getting int from a String Example
以下示例显示如何使用 Integer 类从字符串获取 int。
The following example shows the usage of Integer class to get int from a string.
package com.tutorialspoint;
public class IntegerDemo {
public static void main(String[] args) {
// create a String s and assign value to it
String s = "+120";
// create a Integer object i
Integer i;
// get the value of int from string
i = Integer.valueOf(s);
// print the value
System.out.println( "Integer value of string " + s + " is " + i );
}
}