一、接口的目的

接口的目的是規(guī)范代碼，在寫代碼之前，先通過接口規(guī)定要寫哪些方法

二、定義接口

package com.guoyasoft.implement;

public interface IStudy {
    public boolean doHomeWork(String renwu);
    public int learn(String course);
}

實現(xiàn)接口

public class StudentCY extends Student implements IStudy{

    @Override
    public boolean doHomeWork(String renwu) {
        System.out.println("開始做作業(yè)");
        System.out.println("開始看手機");
        System.out.println("開始玩游戲");
        System.out.println("不做了");
        return false;
    }

    @Override
    public int learn(String course) {
        System.out.println("不想學");
        return 0;
    }

}

public class StudentWL extends Student implements IStudy{

    @Override
    public boolean doHomeWork(String renwu) {
        System.out.println("開始做作業(yè)");
        System.out.println("開始看手機");
        System.out.println("開始玩游戲");
        System.out.println("不做了");
        return false;
    }

    @Override
    public int learn(String course) {
        System.out.println("不想學");
        return 0;
    }

}

3. 測試

package com.guoyasoft.implement;

public class TestStudent {
    public static void main(String[] args) {

        StudentWL wl3=new StudentWL();
        wl3.doHomeWork("家庭作業(yè)");
        wl3.learn("法語");
        
        //向上轉型成接口類型
        IStudy wl4=new StudentWL();
        wl4.doHomeWork("家庭作業(yè)");
        wl4.learn("法語");
    }
}

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