1、說明一
int 是關鍵字，Integer是包裝類，Number是所有數字了的基類（父類）。所以，Number是Integer的基礎，Integer是int的基礎，也稱Integer是int的原型類。通稱，包裝類是基礎數據類型的原型類。
如：System.out.println(Integer.TYPE); // 結果輸出為 int
延伸：
包裝類：Integer、Long、Short、Boolean、Byte、Character、Double、Float
基礎類型：int、long、short、byte、double、float、boolean、char
String對象。
2、說明二
java判斷數據類型的2中形式
（1）強轉為Object后，((Object)a) instanceof Integer 判斷。
（2）賦值給Object對象后，object1 instanceof String判斷。
java按照（2）中形式，判斷數據類型的代碼案例如下：
public class Testbzclass {
public static void main(String[] args) {
Object object1 = null;
int a = 1;
long b = 2;
short c = 3;
boolean d = true;
byte e = 4;
char f = 'p';
double g = 1.22;
float h = 3.0f;
String s = "wahaha";
Integer i = new Integer(7); // 創建int原型類對象
object1 = a;
object1 = b;
object1 = c;
object1 = d;
object1 = e;
object1 = f;
object1 = g;
object1 = h;
object1 = s;
object1 = i.byteValue(); // 以byte類型返回該Integer
object1 = i.intValue(); // 以int型返回該Integer
object1 = i.shortValue(); // 以short型返回該Integer
object1 = i.toString(); // 以String對象返回該Integer
object1 = null; // 未知類型;自定義類型
if (object1 instanceof Integer) {
System.out.println("is Integer");
} else if (object1 instanceof Long) {
System.out.println("is Long");
} else if (object1 instanceof Short) {
System.out.println("is Short");
} else if (object1 instanceof Boolean) {
System.out.println("is Boolean");
} else if (object1 instanceof Byte) {
System.out.println("is byte");
} else if (object1 instanceof Character) {
System.out.println("is Character");
} else if (object1 instanceof Double) {
System.out.println("is Double");
} else if (object1 instanceof Float) {
System.out.println("is Float");
} else if (object1 instanceof String) {
System.out.println("is String");
} else {
System.out.println("unknown type, or yourself type");
}
}
}
復雜版
public class Testbzclass {
public static void main(String[] args) {
Object object1 = null;
int a = 1;
long b = 2;
short c = 3;
boolean d = true;
byte e = 4;
char f = 'p';
double g = 1.22;
float h = 3.0f;
String s = "wahaha";
Integer i = new Integer(17); // 創建int原型類對象
// 輸出原來的數據
System.out.println("object1=" + object1);
System.out.println("a=" + a);
System.out.println("b=" + b);
System.out.println("c=" + c);
System.out.println("d=" + d);
System.out.println("e=" + e);
System.out.println("f=" + f);
System.out.println("g=" + g);
System.out.println("h=" + h);
System.out.println("s=" + s);
System.out.println("i=" + i);
System.out.println();// 換行
object1 = a;
object1 = b;
object1 = c;
object1 = d;
object1 = e;
object1 = f;
object1 = g;
object1 = h;
object1 = s;
object1 = i.byteValue(); // 以byte類型返回該Integer
object1 = i.intValue(); // 以int型返回該Integer
object1 = i.shortValue(); // 以short型返回該Integer
object1 = i.toString(); // 以String對象返回該Integer
object1 = Integer.toBinaryString(i); // 以String對象返回i轉為二進制的字符串
object1 = Integer.toHexString(i);// 以String對象返回i轉為十六進制的字符串
object1 = Integer.toOctalString(i);// 以String對象返回i轉為八進制的字符串
// object1 = null; // 未知類型;自定義類型
// 判斷數據類型
if (object1 instanceof Integer) {
System.out.println(object1 + " is Integer");
} else if (object1 instanceof Long) {
System.out.println(object1 + " is Long");
} else if (object1 instanceof Short) {
System.out.println(object1 + " is Short");
} else if (object1 instanceof Boolean) {
System.out.println(object1 + " is Boolean");
} else if (object1 instanceof Byte) {
System.out.println(object1 + " is byte");
} else if (object1 instanceof Character) {
System.out.println(object1 + " is Character");
} else if (object1 instanceof Double) {
System.out.println(object1 + " is Double");
} else if (object1 instanceof Float) {
System.out.println(object1 + " is Float");
} else if (object1 instanceof String) {
System.out.println(object1 + " is String");
} else {
System.out.println("unknown type, or yourself type");
}
}
}