Java 中原始数据类型与对象数据类型对比示例
原文:https://www . geesforgeks . org/primitive-data-type-vs-object-data-type-in-Java-with-examples/
原始数据类型 : 在 Java 中，原始数据类型是 Java 预定义的数据类型。它们指定任何标准值的大小和类型。Java 有 8 种基本数据类型，即字节、短整型、整型、长整型、浮点型、双精度型、字符型和布尔型。当存储一个基本数据类型时，值将被分配到堆栈中。复制一个变量后，会创建该变量的另一个副本，对复制的变量所做的更改不会反映原始变量的更改。这里有一个 Java 程序来演示 Java 中的所有原始数据类型。
对象数据类型 : 这些也被称为非原始或参考数据类型。之所以叫它们，是因为它们指的是任何特定的物体。与基本数据类型不同，非基本数据类型是由用户在 Java 中创建的。例子包括数组、字符串、类、接口等。当引用变量将被存储时，变量将被存储在堆栈中，而原始对象将被存储在堆中。在对象数据类型中，虽然会创建两个副本，但它们都指向堆中的同一个变量，因此对任何变量的更改都会反映这两个变量的更改。这是一个用 Java 演示数组(一种对象数据类型)的 Java 程序。
Java 中原语和对象数据类型的区别:
现在让我们来看一个演示 Java 中原语和对象数据类型之间区别的程序。
Java 语言(一种计算机语言，尤用于创建网站)
import java.lang.*;
import java.util.*;
class GeeksForGeeks {
public static void main(String ar[])
{
System.out.println("PRIMITIVE DATA TYPES\n");
int x = 10;
int y = x;
System.out.print("Initially: ");
System.out.println("x = " + x + ", y = " + y);
// Here the change in the value of y
// will not affect the value of x
y = 30;
System.out.print("After changing y to 30: ");
System.out.println("x = " + x + ", y = " + y);
System.out.println(
"**Only value of y is affected here "
+ "because of Primitive Data Type\n");
System.out.println("REFERENCE DATA TYPES\n");
int[] c = { 10, 20, 30, 40 };
// Here complete reference of c is copied to d
// and both point to same memory in Heap
int[] d = c;
System.out.println("Initially");
System.out.println("Array c: "
+ Arrays.toString(c));
System.out.println("Array d: "
+ Arrays.toString(d));
// Modifying the value at
// index 1 to 50 in array d
System.out.println("\nModifying the value at "
+ "index 1 to 50 in array d\n");
d[1] = 50;
System.out.println("After modification");
System.out.println("Array c: "
+ Arrays.toString(c));
System.out.println("Array d: "
+ Arrays.toString(d));
System.out.println(
"**Here value of c[1] is also affected "
+ "because of Reference Data Type\n");
}
}
Output
PRIMITIVE DATA TYPES
Initially: x = 10, y = 10
After changing y to 30: x = 10, y = 30
**Only value of y is affected here because of Primitive Data Type
REFERENCE DATA TYPES
Initially
Array c: [10, 20, 30, 40]
Array d: [10, 20, 30, 40]
Modifying the value at index 1 to 50 in array d
After modification
Array c: [10, 50, 30, 40]
Array d: [10, 50, 30, 40]
**Here value of c[1] is also affected because of Reference Data Type
让我们以表格的方式来看看原语和对象数据类型之间的区别。
T29 | attribute | original data type | target | | --- | --- | --- | | origin | Predefined data types | User defined data type | | storage organization | Stored in the stack | Reference variables are stored in the stack, and original objects are stored in the stack. | | Two reference variables are created, but both point to the same object in the heap. | | When making changes in copied variables | The change of is not reflected in the original variable. | Changes reflected by the original objects. | | default | The original data type has no null as the default value. | The default value of the reference variable is null | | example | 字节、短、int、长、浮点、双精度、字符、布尔值 | Array, string class, interface, etc. |版权属于：月萌API www.moonapi.com，转载请注明出处
