1、新建抽象类AbstractUser

package com.kobe.model;public abstract class AbstractUser {    public abstract void work();}

2、新建继承AbstractUser 的 AbstractStudent 、 AbstractTeacher  

package com.kobe.model;public class AbstractTeacher extends AbstractUser{    private int id;    private String name;    @Override    public void work(){        System.out.println("teach");    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }}

package com.kobe.model;public class AbstractStudent extends AbstractUser {    private int id;    private String name;    @Override    public void work(){        System.out.println("study");    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }}

3、在resources目录下新建配置文件 obj.properties

AbstractModel = com.kobe.model.AbstractStudent

4、新建工厂类  getUser方法 从配置文件中读取配置信息

package com.kobe.test;import com.kobe.model.AbstractUser;import java.util.Properties;public class AbstractFactory {    public static AbstractUser getUser(){        try {            Properties prop = new Properties();            prop.load(simpleFactory.class.getClassLoader().getResourceAsStream("obj.properties"));            String model = (String) prop.get("AbstractModel");            AbstractUser u = (AbstractUser) Class.forName(model).newInstance();            return u;        } catch (Exception e) {            e.printStackTrace();        }        return null;    }}

5、新建测试类

package com.kobe.test;import com.kobe.model.AbstractUser;public class testAbstract {    public static void main(String[] args) {        AbstractUser u1 = AbstractFactory.getUser();        u1.work();    }}

输出结果是  study

如果把配置文件中的 AbstractModel的值换成 com.kobe.model.AbstractTeacher  

输出就变成 teach  

根据配置文件创建不同的实体类，不需修改java代码