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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