Bean的实例化模式
Spring为Bean提供了多种实例化方式,通常包括4种方式。(也就是说在Spring中为Bean对象的创建准备了多种方案,目的是:更加灵活)
● 第一种:通过构造方法实例化
● 第二种:通过简单工厂模式实例化
● 第三种:通过factory-bean实例化
● 第四种:通过FactoryBean接口实例化
通过构造方法实例化
ConstructorBean.java
package com.powercode.spring6.beans;
public class ConstructorBean {
public ConstructorBean(){
}
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="constructorBean" class="com.powercode.spring6.beans.ConstructorBean"></bean>
</beans>
测试程序`
@Test
public void testConstrucotrBean(){
Logger logger = LoggerFactory.getLogger(FirstSpringTest.class);
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring9.xml");
ConstructorBean constructorBean = applicationContext.getBean("constructorBean",ConstructorBean.class);
System.out.println(constructorBean);
}
/usr/lib/jvm/java-17-openjdk/bin/java -ea -Didea.test.cyclic.buffer.size=1048576 -javaagent:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar=36789:/opt/intellij-idea-ultimate-edition/bin -Dfile.encoding=UTF-8 -classpath /home/meowrain/.m2/repository/org/junit/platform/junit-platform-launcher/1.10.1/junit-platform-launcher-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-engine/1.10.1/junit-platform-engine-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.10.1/junit-jupiter-engine-5.10.1.jar:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit5-rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit-rt.jar:/home/meowrain/IdeaProjects/spring_first/target/test-classes:/home/meowrain/IdeaProjects/spring_first/target/classes:/home/meowrain/.m2/repository/org/springframework/spring-context/6.1.0-SNAPSHOT/spring-context-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-aop/6.1.0-SNAPSHOT/spring-aop-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-beans/6.1.0-SNAPSHOT/spring-beans-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-core/6.1.0-SNAPSHOT/spring-core-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-jcl/6.1.0-SNAPSHOT/spring-jcl-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-expression/6.1.0-SNAPSHOT/spring-expression-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-observation/1.12.0/micrometer-observation-1.12.0.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-commons/1.12.0/micrometer-commons-1.12.0.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.10.1/junit-jupiter-api-5.10.1.jar:/home/meowrain/.m2/repository/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-commons/1.10.1/junit-platform-commons-1.10.1.jar:/home/meowrain/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-core/2.19.0/log4j-core-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-api/2.19.0/log4j-api-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-slf4j2-impl/2.19.0/log4j-slf4j2-impl-2.19.0.jar:/home/meowrain/.m2/repository/org/slf4j/slf4j-api/2.0.0/slf4j-api-2.0.0.jar com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit5 com.powercode.spring6.test.FirstSpringTest,testConstrucotrBean
2024-01-11 09:28:44 658 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@556d0826
2024-01-11 09:28:44 843 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from class path resource [spring9.xml]
2024-01-11 09:28:44 868 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'constructorBean'
com.powercode.spring6.beans.ConstructorBean@6058e535
通过简单工厂模式实例化
第一步:定义一个Bean
package com.powercode.spring6.beans;
public class Fruit {
}
第二步:编写简单工厂模式当中的工厂类
package com.powercode.spring6.beans;
public class FruitFactory {
public static Fruit get(){
return new Fruit();
}
}
第三步:在Spring配置文件中指定创建该Bean的方法(使用factory-method属性指定)
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="fruitBean" class="com.powercode.spring6.beans.FruitFactory" factory-method="get"></bean>
</beans>
第四步:编写测试程序
@Test
public void testSimpleFactoryMode(){
Logger logger = LoggerFactory.getLogger(FirstSpringTest.class);
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring10.xml");
Fruit fruit = applicationContext.getBean("fruitBean", Fruit.class);
System.out.println(fruit);
}
/usr/lib/jvm/java-17-openjdk/bin/java -ea -Didea.test.cyclic.buffer.size=1048576 -javaagent:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar=44855:/opt/intellij-idea-ultimate-edition/bin -Dfile.encoding=UTF-8 -classpath /home/meowrain/.m2/repository/org/junit/platform/junit-platform-launcher/1.10.1/junit-platform-launcher-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-engine/1.10.1/junit-platform-engine-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.10.1/junit-jupiter-engine-5.10.1.jar:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit5-rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit-rt.jar:/home/meowrain/IdeaProjects/spring_first/target/test-classes:/home/meowrain/IdeaProjects/spring_first/target/classes:/home/meowrain/.m2/repository/org/springframework/spring-context/6.1.0-SNAPSHOT/spring-context-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-aop/6.1.0-SNAPSHOT/spring-aop-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-beans/6.1.0-SNAPSHOT/spring-beans-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-core/6.1.0-SNAPSHOT/spring-core-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-jcl/6.1.0-SNAPSHOT/spring-jcl-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-expression/6.1.0-SNAPSHOT/spring-expression-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-observation/1.12.0/micrometer-observation-1.12.0.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-commons/1.12.0/micrometer-commons-1.12.0.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.10.1/junit-jupiter-api-5.10.1.jar:/home/meowrain/.m2/repository/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-commons/1.10.1/junit-platform-commons-1.10.1.jar:/home/meowrain/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-core/2.19.0/log4j-core-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-api/2.19.0/log4j-api-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-slf4j2-impl/2.19.0/log4j-slf4j2-impl-2.19.0.jar:/home/meowrain/.m2/repository/org/slf4j/slf4j-api/2.0.0/slf4j-api-2.0.0.jar com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit5 com.powercode.spring6.test.FirstSpringTest,testSimpleFactoryMode
2024-01-11 09:36:05 538 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@66ce957f
2024-01-11 09:36:05 670 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from class path resource [spring10.xml]
2024-01-11 09:36:05 698 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'fruitBean'
com.powercode.spring6.beans.Fruit@3301500b
进程已结束,退出代码为 0
通过factory-bean实例化
这种方式本质上是:通过工厂方法模式进行实例化。
第一步:定义一个Bean
package com.powercode.spring6.beans;
public class Fruit {
}
第二步:定义具体工厂类,工厂类中定义实例方法
package com.powercode.spring6.beans;
public class FruitFactory {
public static Fruit get(){
return new Fruit();
}
}
第三步,编写spring配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- <bean id="fruitBean" class="com.powercode.spring6.beans.FruitFactory" factory-method="get"></bean>-->
<bean id="fruitFactory" class="com.powercode.spring6.beans.FruitFactory"></bean>
<bean id="fruitBean" class="com.powercode.spring6.beans.Fruit" factory-bean="fruitFactory" factory-method="get"></bean>
</beans>
上面注释掉的用的是简单工厂模式,下面没注释掉的,直接指定一个factory-bean的,就是用的工厂方法模式
注意这里必须要在factroy-bean对应的类中实现一个get方法,注意,简单工厂模式下,也就是往上面一点的,就是要把get方法设置为静态的,但是下面我们现在用的是工厂方法模式,不需要加static
加上spring反而找不到get方法了!
第四步:编写测试程序
@Test
public void testFactoryMethodMode(){
Logger logger = LoggerFactory.getLogger(FirstSpringTest.class);
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring10.xml");
Fruit fruit = applicationContext.getBean("fruitBean", Fruit.class);
System.out.println(fruit);
}
/usr/lib/jvm/java-17-openjdk/bin/java -ea -Didea.test.cyclic.buffer.size=1048576 -javaagent:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar=35009:/opt/intellij-idea-ultimate-edition/bin -Dfile.encoding=UTF-8 -classpath /home/meowrain/.m2/repository/org/junit/platform/junit-platform-launcher/1.10.1/junit-platform-launcher-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-engine/1.10.1/junit-platform-engine-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.10.1/junit-jupiter-engine-5.10.1.jar:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit5-rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit-rt.jar:/home/meowrain/IdeaProjects/spring_first/target/test-classes:/home/meowrain/IdeaProjects/spring_first/target/classes:/home/meowrain/.m2/repository/org/springframework/spring-context/6.1.0-SNAPSHOT/spring-context-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-aop/6.1.0-SNAPSHOT/spring-aop-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-beans/6.1.0-SNAPSHOT/spring-beans-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-core/6.1.0-SNAPSHOT/spring-core-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-jcl/6.1.0-SNAPSHOT/spring-jcl-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-expression/6.1.0-SNAPSHOT/spring-expression-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-observation/1.12.0/micrometer-observation-1.12.0.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-commons/1.12.0/micrometer-commons-1.12.0.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.10.1/junit-jupiter-api-5.10.1.jar:/home/meowrain/.m2/repository/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-commons/1.10.1/junit-platform-commons-1.10.1.jar:/home/meowrain/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-core/2.19.0/log4j-core-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-api/2.19.0/log4j-api-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-slf4j2-impl/2.19.0/log4j-slf4j2-impl-2.19.0.jar:/home/meowrain/.m2/repository/org/slf4j/slf4j-api/2.0.0/slf4j-api-2.0.0.jar com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit5 com.powercode.spring6.test.FirstSpringTest,testFactoryMethodMode
2024-01-11 09:54:47 431 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5bfa8cc5
2024-01-11 09:54:47 571 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 2 bean definitions from class path resource [spring10.xml]
2024-01-11 09:54:47 600 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'fruitFactory'
2024-01-11 09:54:47 612 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'fruitBean'
com.powercode.spring6.beans.Fruit@57a4d5ee
进程已结束,退出代码为 0
通过FactoryBean接口实例化
以上的第三种方式中,factory-bean是我们自定义的,factory-method也是我们自己定义的。
在Spring中,当你编写的类直接实现FactoryBean接口之后,factory-bean不需要指定了,factory-method也不需要指定了。
factory-bean会自动指向实现FactoryBean接口的类,factory-method会自动指向getObject()方法。
第一步:定义一个bean
package com.powercode.spring6.beans;
public class Person {
}
第二步:编写一个类实现FactoryBean接口
package com.powercode.spring6.beans;
import org.springframework.beans.factory.FactoryBean;
public class PersonFactory implements FactoryBean<Person> {
@Override
public Person getObject() throws Exception {
return new Person();
}
@Override
public Class<?> getObjectType() {
return null;
}
@Override
public boolean isSingleton(){
return true;
}
}
第三步:编写xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="personBean" class="com.powercode.spring6.beans.PersonFactory"></bean>
</beans>
第四步:编写测试函数
@Test
public void testFactoryMethodMode2(){
Logger logger = LoggerFactory.getLogger(FirstSpringTest.class);
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring10.xml");
Person person = applicationContext.getBean("personBean", Person.class);
System.out.println(person);
}
/usr/lib/jvm/java-17-openjdk/bin/java -ea -Didea.test.cyclic.buffer.size=1048576 -javaagent:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar=32877:/opt/intellij-idea-ultimate-edition/bin -Dfile.encoding=UTF-8 -classpath /home/meowrain/.m2/repository/org/junit/platform/junit-platform-launcher/1.10.1/junit-platform-launcher-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-engine/1.10.1/junit-platform-engine-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.10.1/junit-jupiter-engine-5.10.1.jar:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit5-rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit-rt.jar:/home/meowrain/IdeaProjects/spring_first/target/test-classes:/home/meowrain/IdeaProjects/spring_first/target/classes:/home/meowrain/.m2/repository/org/springframework/spring-context/6.1.0-SNAPSHOT/spring-context-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-aop/6.1.0-SNAPSHOT/spring-aop-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-beans/6.1.0-SNAPSHOT/spring-beans-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-core/6.1.0-SNAPSHOT/spring-core-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-jcl/6.1.0-SNAPSHOT/spring-jcl-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-expression/6.1.0-SNAPSHOT/spring-expression-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-observation/1.12.0/micrometer-observation-1.12.0.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-commons/1.12.0/micrometer-commons-1.12.0.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.10.1/junit-jupiter-api-5.10.1.jar:/home/meowrain/.m2/repository/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-commons/1.10.1/junit-platform-commons-1.10.1.jar:/home/meowrain/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-core/2.19.0/log4j-core-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-api/2.19.0/log4j-api-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-slf4j2-impl/2.19.0/log4j-slf4j2-impl-2.19.0.jar:/home/meowrain/.m2/repository/org/slf4j/slf4j-api/2.0.0/slf4j-api-2.0.0.jar com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit5 com.powercode.spring6.test.FirstSpringTest,testFactoryMethodMode2
2024-01-11 10:58:33 850 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5bfa8cc5
2024-01-11 10:58:33 956 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 3 bean definitions from class path resource [spring10.xml]
2024-01-11 10:58:33 979 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'fruitFactory'
2024-01-11 10:58:33 986 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'fruitBean'
2024-01-11 10:58:33 988 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'personBean'
com.powercode.spring6.beans.Person@70f43b45
进程已结束,退出代码为 0
FactoryBean在Spring中是一个接口。被称为“工厂Bean”。“工厂Bean”是一种特殊的Bean。所有的“工厂Bean”都是用来协助Spring框架来创建其他Bean对象的。
BeanFactory和FactoryBean的区别
BeanFactory
Spring IoC容器的顶级对象,BeanFactory被翻译为“Bean工厂”,在Spring的IoC容器中,“Bean工厂”负责创建Bean对象。
BeanFactory是工厂。
FactoryBean
FactoryBean:它是一个Bean,是一个能够辅助Spring实例化其它Bean对象的一个Bean。
在Spring中,Bean可以分为两类:
● 第一类:普通Bean
● 第二类:工厂Bean(记住:工厂Bean也是一种Bean,只不过这种Bean比较特殊,它可以辅助Spring实例化其它Bean对象。)
注入自定义Date
我们前面说过,java.util.Date在Spring中被当做简单类型,简单类型在注入的时候可以直接使用value属性或value标签来完成。但我们之前已经测试过了,对于Date类型来说,采用value属性或value标签赋值的时候,对日期字符串的格式要求非常严格,必须是这种格式的:Mon Oct 10 14:30:26 CST 2022。其他格式是不会被识别的。如以下代码:
package com.powercode.spring6.beans;
import java.util.Date;
public class Human {
private Date date;
public Human(Date date) {
this.date = date;
}
public void setDate(Date date) {
this.date = date;
}
@Override
public String toString() {
return "Human{" +
"date=" + date +
'}';
}
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="dateBean" class="com.powercode.spring6.beans.DateFactory">
<constructor-arg name="date">
<value>2022-12-10</value>
</constructor-arg>
</bean>
<bean id="humanBean" class="com.powercode.spring6.beans.Human">
<constructor-arg name="date" ref="dateBean"></constructor-arg>
</bean>
</beans>
我们上面构建的birth不是标准格式,会报错
我们需要编写一个DateFactoryBean,这个类实现FactoryBean接口!
package com.powercode.spring6.beans;
import org.springframework.beans.factory.FactoryBean;
import java.text.SimpleDateFormat;
import java.util.Date;
public class DateFactory implements FactoryBean<Date> {
private String date;
public DateFactory(String date) {
this.date = date;
}
@Override
public Date getObject() throws Exception {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
return simpleDateFormat.parse(date);
}
@Override
public Class<?> getObjectType() {
return null;
}
@Override
public boolean isSingleton() {
return FactoryBean.super.isSingleton();
}
}
/usr/lib/jvm/java-17-openjdk/bin/java -ea -Didea.test.cyclic.buffer.size=1048576 -javaagent:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar=46505:/opt/intellij-idea-ultimate-edition/bin -Dfile.encoding=UTF-8 -classpath /home/meowrain/.m2/repository/org/junit/platform/junit-platform-launcher/1.10.1/junit-platform-launcher-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-engine/1.10.1/junit-platform-engine-1.10.1.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.10.1/junit-jupiter-engine-5.10.1.jar:/opt/intellij-idea-ultimate-edition/lib/idea_rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit5-rt.jar:/opt/intellij-idea-ultimate-edition/plugins/junit/lib/junit-rt.jar:/home/meowrain/IdeaProjects/spring_first/target/test-classes:/home/meowrain/IdeaProjects/spring_first/target/classes:/home/meowrain/.m2/repository/org/springframework/spring-context/6.1.0-SNAPSHOT/spring-context-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-aop/6.1.0-SNAPSHOT/spring-aop-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-beans/6.1.0-SNAPSHOT/spring-beans-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-core/6.1.0-SNAPSHOT/spring-core-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-jcl/6.1.0-SNAPSHOT/spring-jcl-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/org/springframework/spring-expression/6.1.0-SNAPSHOT/spring-expression-6.1.0-20231116.112758-846.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-observation/1.12.0/micrometer-observation-1.12.0.jar:/home/meowrain/.m2/repository/io/micrometer/micrometer-commons/1.12.0/micrometer-commons-1.12.0.jar:/home/meowrain/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.10.1/junit-jupiter-api-5.10.1.jar:/home/meowrain/.m2/repository/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar:/home/meowrain/.m2/repository/org/junit/platform/junit-platform-commons/1.10.1/junit-platform-commons-1.10.1.jar:/home/meowrain/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-core/2.19.0/log4j-core-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-api/2.19.0/log4j-api-2.19.0.jar:/home/meowrain/.m2/repository/org/apache/logging/log4j/log4j-slf4j2-impl/2.19.0/log4j-slf4j2-impl-2.19.0.jar:/home/meowrain/.m2/repository/org/slf4j/slf4j-api/2.0.0/slf4j-api-2.0.0.jar com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit5 com.powercode.spring6.test.FirstSpringTest,testDate
2024-01-11 11:33:58 857 [main] DEBUG org.springframework.context.support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@75459c75
2024-01-11 11:33:58 942 [main] DEBUG org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loaded 2 bean definitions from class path resource [spring11.xml]
2024-01-11 11:33:58 960 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'dateBean'
2024-01-11 11:33:58 972 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'humanBean'
Human{date=Sat Dec 10 00:00:00 CST 2022}
进程已结束,退出代码为 0