阿里面试官：小伙子，你给我说一下Spring Bean初始化的几种常规方式吧
2021-04-12 18:27
标签：div ack 面试 https oid his default 构造 com 通过构造方法实例化 输出/异步加载bean 大家看完有什么不懂的可以在下方留言讨论，也可以关注我私信问我，我看到后都会回答的。也欢迎大家关注我的公众号：前程有光，金三银四跳槽面试季，整理了1000多道将近500多页pdf文档的Java面试题资料，文章都会在里面更新，整理的资料也会放在里面。谢谢你的观看，觉得文章对你有帮助的话记得关注我点个赞支持一下！ 阿里面试官：小伙子，你给我说一下Spring Bean初始化的几种常规方式吧 标签：div ack 面试 https oid his default 构造 com 原文地址：https://www.cnblogs.com/lwh1019/p/13347639.html前言
通过静态工厂实例化
通过实例工厂实例化
通过FactoryBean实例化RumenzA实体类
package com.rumenz;
public class RumenzA {
private String id;
private String name;
public static RumenzA createRumenzA(){
RumenzA rumenzA=new RumenzA();
rumenzA.setId("123");
rumenzA.setName("入门小站");
return rumenzA;
}
public RumenzA() {
System.out.println("RumenzA 无参构造方法");
}
public RumenzA(String id) {
this.id = id;
System.out.println("ID构造方法");
}
// set get省略
}
构造方法
beans.xml
DemoApplication.java
package com.rumenz;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DemoApplication {
public static void main(String[] args) {
ClassPathXmlApplicationContext ca=new ClassPathXmlApplicationContext("beans.xml");
RumenzA rumenzA=(RumenzA)ca.getBean("rumenz");
}
}
输出
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rumenz‘
RumenzA 无参构造方法
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rumenz1‘
ID构造方法
静态工厂
beans.xml
RumenzFactory工厂类
package com.rumenz;
public class RumenzFactory {
//静态方法
public static RumenzA rumenzFactory(){
return new RumenzA();
}
public static RumenzA rumenzFactory(String id){
return new RumenzA(id);
}
}
DemoApplication.java
package com.rumenz;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DemoApplication {
public static void main(String[] args) {
ClassPathXmlApplicationContext ca=new ClassPathXmlApplicationContext("beans.xml");
}
}
输出
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rFactory‘
RumenzA 无参构造方法
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rFactory1‘
ID构造方法
实例工厂实例化
RumenzFactory.java
package com.rumenz;
public class RumenzFactory {
//不能用静态方法
public RumenzA rumenzFactory(){
return new RumenzA();
}
public RumenzA rumenzFactory(String id){
return new RumenzA(id);
}
}
DemoApplication.java
package com.rumenz;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DemoApplication {
public static void main(String[] args) {
ClassPathXmlApplicationContext ca=new ClassPathXmlApplicationContext("beans.xml");
//RumenzA rumenzA=(RumenzA)ca.getBean("rFactory1");
}
}
输出
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rumenz‘
RumenzA 无参构造方法
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rumenz1‘
ID构造方法
通过FactoryBean实例化
beans.xml
RumenzAFactoryBean.java
package com.rumenz;
import org.springframework.beans.factory.FactoryBean;
public class RumenzAFactoryBean implements FactoryBean {
@Override
public Object getObject() throws Exception {
return RumenzA.createRumenzA();
}
@Override
public Class> getObjectType() {
return RumenzA.class;
}
}
DemoApplication.java
package com.rumenz;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DemoApplication {
public static void main(String[] args) {
ClassPathXmlApplicationContext ca=new ClassPathXmlApplicationContext("beans.xml");
RumenzA rumenzA=(RumenzA)ca.getBean("rumenz-by-factoryBean");
}
}
xxx.DefaultListableBeanFactory - Creating shared instance of singleton bean ‘rumenz-by-factoryBean‘
RumenzA 无参构造方法
最后
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