java判定数据（对象）类型

1、说明一

int 是关键字，Integer是包装类，Number是所有数字了的基类（父类）。所以，Number是Integer的基础，Integer是int的基础，也称Integer是int的原型类。通称，包装类是基础数据类型的原型类。

如：System.out.println(Integer.TYPE);  // 结果输出为 int

延伸：

包装类：Integer、Long、Short、Boolean、Byte、Character、Double、Float

基础类型：int、long、short、byte、double、float、boolean、char

String对象。

2、说明二

java判断数据类型的2中形式
（1）强转为Object后，((Object)a) instanceof Integer 判断。
（2）赋值给Object对象后，object1 instanceof String判断。

 

java按照（2）中形式，判断数据类型的代码案例如下：

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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); // 创建int原型类对象         object1 = a;         object1 = b;         object1 = c;         object1 = d;         object1 = e;         object1 = f;         object1 = g;         object1 = h;         object1 = s;         object1 = i.byteValue(); // 以byte类型返回该Integer         object1 = i.intValue(); // 以int型返回该Integer         object1 = i.shortValue(); // 以short型返回该Integer         object1 = i.toString(); // 以String对象返回该Integer         object1 = null; // 未知类型;自定义类型           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");         }       }   }

　　

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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); // 创建int原型类对象           // 输出原来的数据         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();// 换行           object1 = a;         object1 = b;         object1 = c;         object1 = d;         object1 = e;         object1 = f;         object1 = g;         object1 = h;         object1 = s;         object1 = i.byteValue(); // 以byte类型返回该Integer         object1 = i.intValue(); // 以int型返回该Integer         object1 = i.shortValue(); // 以short型返回该Integer         object1 = i.toString(); // 以String对象返回该Integer         object1 = Integer.toBinaryString(i); // 以String对象返回i转为二进制的字符串         object1 = Integer.toHexString(i);// 以String对象返回i转为十六进制的字符串         object1 = Integer.toOctalString(i);// 以String对象返回i转为八进制的字符串         // object1 = null; // 未知类型;自定义类型           // 判断数据类型         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");         }       }   }