Share a simple example of java polymorphism

A simple example of java polymorphism: first create an interface; then create two classes to determine the content of the speech; then print the time while speaking; and finally create a test class to run.

Simple example of java polymorphism:

The three necessary conditions for polymorphism (implementation):

• Need to have inheritance (inherit class, inherit abstract class, implement interface)

• Need to have overriding

• Reference execution of parent type subtype

Example: Using polymorphism to realize speaking and printing the time of saying this sentence

Ideas and code:

1. Since I don’t know that the content of the speech is too abstract, I created an interface

public interface TimeSpeek { public abstract void getTimeSpeek(); }

2. The methods in the interface need to be implemented, so now I need to create two classes to determine the content of the speech

第一句话 public class SpeekOne implements TimeSpeek { @Override public void getTimeSpeek() { // TODO Auto-generated method stub System.out.println("停车坐爱枫林晚"); } } 第二句话 public class SpeekTwo implements TimeSpeek { @Override public void getTimeSpeek() { // TODO Auto-generated method stub System.out.println("霜叶红于二月花"); } }

3. After the content of the speech is determined, you need to print the time while speaking

import java.util.Date; public class GetTime { public GetTime(TimeSpeek getTimeSpeek) { this.getTime(getTimeSpeek); } public void getTime(TimeSpeek getTimeSpeek) { System.out.println("开始时间：" + new Date().getTime()); getTimeSpeek.getTimeSpeek(); } }

4. Create a test class and run

public class Test { public static void main(String[] args) { SpeekOne so = new SpeekOne(); SpeekTwo st = new SpeekTwo(); new GetTime(so); new GetTime(st); } }

Get the result through the above steps:

开始时间：1565510695244 停车坐爱枫林晚 开始时间：1565510695245 霜叶红于二月花

Related learning recommendations:java basics

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