Java类class newInstance（）方法及示例

类class newInstance()方法 (Class class newInstance() method)

• newInstance() method is available in java.lang package.

  newInstance()方法在java.lang包中可用。

• newInstance() method is used to create a new instance of the class denoted by this Class object.

  newInstance()方法用于创建此Class对象表示的类的新实例。

• newInstance() 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.

  newInstance()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• newInstance() method does not throw various exceptions at the time creating a new instance of the class.

  newInstance()方法在创建类的新实例时不会引发各种异常。

  • IllegalAccessException: This exception may raise when this Class or its constructor is not accessible.IllegalAccessException ：当无法访问此类或其构造函数时，可能会引发此异常。
  • InstantiationException: This exception may raise when class instantiation fails.InstantiationException ：类实例化失败时，可能会引发此异常。
  • ExceptionInInitializerError: This exception may raise when the initialization stimulated by the method fails.ExceptionInInitializerError ：当方法激发的初始化失败时，可能会引发此异常。
  • SecurityException: This exception may raise when the security manager exists.SecurityException ：当安全管理器存在时，可能会引发此异常。

Syntax:

句法：

    public Object  newInstance();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of this method is Object, it returns a new instance of the class.

该方法的返回类型为Object ，它返回该类的新实例。

Example:

例：

// Java program to demonstrate the example 
// of Object newInstance () method of Class 

public class NewInstanceOfClass {
    public static void main(String[] args) throws Exception {
        // Create and Return String class
        StringBuilder s1 = new StringBuilder();
        Class cl1 = s1.getClass();

        // We are creating a new instance of the
        // class denoted by this object cl1
        // by using newInstance() method
        Object s2 = cl1.newInstance();
        Class cl2 = s2.getClass();

        // Display Instance
        System.out.println("Instance s1: " + cl1.toString());
        System.out.println("Instance s2: " + cl2.toString());
    }
}

Output

输出量

Instance s1: class java.lang.StringBuilder
Instance s2: class java.lang.StringBuilder

翻译自: https://www.includehelp.com/java/class-class-newinstance-method-with-example.aspx