Bean

db.properties

StudentServiceImpl=com.ycz.service.impl.StudentServiceImpl
StudentServiceImpl2=com.ycz.service.impl.StudentServiceImpl2

StudentService

package com.ycz.service;/*
 @author ycz
 @date 2021-10-14-15:17
*/
​
public interface StudentService {
​
    void add();
    void update();
​
}

StudentServiceImpl

package com.ycz.service.impl;/*
 @author ycz
 @date 2021-10-14-15:17
*/
​
import com.ycz.service.StudentService;
​
public class StudentServiceImpl2 implements StudentService {
    @Override
    public void add() {
        System.out.println("add222的方法");
    }
​
    @Override
    public void update() {
        System.out.println("更新2222的方法");
    }
}

编写Factory

package com.ycz.factory;/*
 @author ycz
 @date 2021-10-14-15:19
*/
​
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;
​
public class SpringBeanFactory {
​
    private static Properties pp;
    static {
        try {
            pp=new Properties();
            pp.load(ClassLoader.getSystemResourceAsStream("db.properties"));
         //   String studentServiceImpl = pp.getProperty("StudentServiceImpl");
           // System.out.println(studentServiceImpl);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
​
    public static Object getBean(String BeanName) throws Exception {
        String bean = pp.getProperty(BeanName);
        Class<?> aClass = Class.forName(bean);
        Object obj = aClass.getDeclaredConstructor().newInstance();
        return obj;
​
​
    }
​
}

测试：

@Test
public void t3() throws Exception {
    StudentService studentServiceImpl =
            (StudentService) SpringBeanFactory.getBean("StudentServiceImpl2");
    studentServiceImpl.add();
}

结果：

add222的方法

\