写一篇最好懂的FactoryBean-蒲公英云

写一篇最好懂的FactoryBean

小灰灰 2023-07-24 11:40 55阅读 0赞

FactoryBean的作用主要是帮助动态代理注册到spring容器。

Person:

package com.mtons.mblog.modules.entity;
/**
 * @author Administrator
 */
public class Person {
    private String name;
    private String address;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Person() {
    }
}

PersonFactoryBean:

package com.mtons.mblog.modules.entity;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.stereotype.Component;
/**
 * @author Administrator
 */
@Component(value = "personFactoryBean")
public class PersonFactoryBean implements FactoryBean<Person> {
    private String personInfo = "gh2,22,address2";
    /**
     * 返回由FactoryBean创建的bean实例，如果isSingleton()返回true，则该实例会
     * 放到Spring容器中单实例缓存池中。
     * 通过factorybean代理对象注册给spring，否则代理对象没有文件无法注册给spring的
     * @return
     * @throws Exception
     */
    @Override
    public Person getObject() throws Exception {
        Person person =  new  Person () ;
        String []  infos =  personInfo.split ( "," ) ;
        person.setName(infos[0]);
        person.setAddress(infos[1]);
        person.setAge(Integer.parseInt(infos[2]));
        return person;
    }
    /**
     * 返回FactoryBean创建的bean类型。
     * @return
     */
    @Override
    public Class<Person> getObjectType() {
        return Person.class;
    }
    @Override
    public boolean isSingleton() {
        return true;
    }
    /**
     * 接受逗号分割符设置属性信息
     * @param personInfo
     */
    public void setPersonInfo(String personInfo) {
        this.personInfo = personInfo;
    }
}

FactortBeanlTest:

package com.mtons.mblog.modules.service.impl;
import com.mtons.mblog.BootApplication;
import com.mtons.mblog.modules.entity.Person;
import com.mtons.mblog.modules.entity.PersonFactoryBean;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;
/**
 * post service test
 *
 * @author saxing 2019/4/5 17:32
 */
//@RunWith(SpringRunner.class)
@SpringBootTest(classes = BootApplication.class)
public class FactortBeanlTest {
    @Autowired
    PostServiceImpl postService;
        public static void main(String[] args) {
            ApplicationContext context = SpringApplication.run(BootApplication.class, args);
            /**
             * 当调用getBean("personFactory") 时，Spring通过反射机制发现PersonFactoryBean实现了FactoryBean的接口，
             * 这时Spring容器就调用接口方法PersonFactoryBean的getObject()方法返回。
             * 如果希望获取PersonFactoryBean的实例，则需要在使用getBean(beanName) 方法时在beanName前显示的加上 "&"
             * 前缀，例如getBean("&personFactory")。
             */
            PersonFactoryBean personFactory = (PersonFactoryBean) context.getBean("&personFactoryBean");
            personFactory.setPersonInfo("gh2,address2,22");
            try {
                Person person = personFactory.getObject();
                //System.out.println("ggggggggggggggggggggggggggggggggggggggggggggggggggggg");
                System.out.println(person.getName()+","+person.getAge()+","+person.getAddress());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
}