类class cast()方法 (Class class cast() method)
cast() method is available in java.lang package.
在java.lang包中提供了cast()方法 。
cast() method casts this Object to the class or an interface denoted by this Class object.
cast()方法将此Object强制转换为该Class或此Class对象表示的接口。
cast() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
cast()方法是一个非静态方法，只能通过类对象访问，如果尝试使用类名访问该方法，则会收到错误消息。
cast() method may throw ClassCastException at the time of casting an Object.
cast()方法可能会在投射对象时抛出ClassCastException 。
ClassCastException: In this exception when the given object is not null.
ClassCastException ：在此异常中，给定对象不为null。
Syntax:
句法：
public Type cast(Object o);
Parameter(s):
参数：
Object o – represents the object to be cast.
对象o –表示要投射的对象。
Return value:
返回值：
The return type of this method is Type, it returns the following values based on the given cases,
此方法的返回类型为Type ，它根据给定的情况返回以下值：
It returns the casting object.
它返回转换对象。
It returns null when the given Object is null.
当给定的Object为null时，它返回null。
Example:
例：
// Java program to demonstrate the example
// of Type cast(Object o) method of Class
class A1 {
// A1 Blank implementation
}
class B1 extends A1 {
// B1 Blank implementation
}
public class MainClass {
public static void main(String[] args) {
// Creting an instance of MainClass
MainClass mc = new MainClass();
// Display Class
System.out.println("mc.getClass():" + mc.getClass());
// Creating an instance of class A1 and B1
A1 a = new A1();
B1 b = new B1();
// Casting object b to a by using cast(b) method
Object a1 = A1.class.cast(b);
// Display Class of object a , b and a1
System.out.println("a.getClass(): " + a.getClass());
System.out.println("b.getClass(): " + b.getClass());
System.out.println("a1.getClass(): " + a1.getClass());
}
}
Output
输出量
mc.getClass():class MainClass
a.getClass(): class A1
b.getClass(): class B1
a1.getClass(): class B1
翻译自: https://www.includehelp.com/java/class-class-cast-method-with-example.aspx
