Spring IoC容器概述
- Spring容器即体现了IoC原理
- Spring容器通过读取配置元数据负责对Beans实例化、配置和装配
- 配置元数据可以用XML、Java注解或Java代码来描述
Spring容器会读取配置文件，放置对象到容器里面，自动帮你生成对象。
BeanFactory
帮你把用的对象实例化，用的是反射技术。
BeanFactory实际上也是工厂模式。
课上例子……
ApplicationContext
是BeanFactory的子接口，比BeanFactory功能更多。
是它的超级。
有四个实现类。（ApplicationContext的实现）
- ClassPathXmlApplicationContext
基于XML文件的配置，放置在文件根目录下 - FileSystemXmlApplicationContext
XML文件放操作系统的路径下（C：/ D：什么的） - XmlWebApplicationContext
基于WEB程序的配置 - AnnotationConfigApplicationContext
完全注解方式
超集=提供更多的东西
Bean概述
构造方法实例化
项目结构
Desk.java
package com;
public class Desk {
private static Desk desk;
public Desk() {
System.out.println("Desk构造方法");
}
public static Desk createInstance() {
System.out.println("createInstance");
if(desk==null)
desk = new Desk();
return desk;
}
}
Test.java
package com;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
Desk desk = (Desk)ctx.getBean("Desk");
}
}
运行结果
静态工厂方式实例化
在构造方法实例化的基础上做修改即可
修改Bean.xml文件
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
增加Factory-method属性即可
<bean id="Desk" class="com.Desk" factory-method="createInstance"/>
</beans>
实例工厂实例化
项目结构
Chair.java
package com;
public class Chair {
public Chair() {
System.out.println("Chair无参数构造");
}
}
ChairFactory.java
package com;
public class ChairFactory {
public Chair create() {
return new Chair();
}
}
Desk.java
package com;
public class Desk {
private static Desk desk;
public Desk() {
System.out.println("Desk构造方法");
}
public static Desk createInstance() {
System.out.println("createInstance");
if(desk==null)
desk = new Desk();
return desk;
}
}
Test.java
package com;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
Chair chair=(Chair)ctx.getBean("Chair");
}
}
Beans.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<bean id="Desk" class="com.Desk" factory-method="createInstance"/>
<bean id="ChairFactory" class="com.ChairFactory"></bean>
<!-- factory-bean的属性值是上面的id值，不是类名 -->
<!-- factory-methid的属性值是工厂类的方法名 -->
<bean id="Chair" factory-bean="ChairFactory" factory-method="create"></bean>
</beans>
运行结果
Bean的生命周期
实现Aware接口 与 使用自定义方法配置
就是系统的方法与 用户自定义的方法
项目结构
BeanLife.java
package com;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
//实现接口
public class BeanLife implements ApplicationContextAware, InitializingBean, DisposableBean{
private ApplicationContext ctx;
private String name;
public void setName(String name) {
this.name = name;
System.out.println("setName属性的赋值");
}
public BeanLife() {
System.out.println("BeanLife的无参构造方法");
}
public void show() {
System.out.println(name);
}
@Override
public void setApplicationContext(ApplicationContext arg0) throws BeansException {
ctx = arg0;//让自己的类可以用传来的ApplicationContext参数
System.out.println("applicationAware");
}
@Override
public void destroy() throws Exception {
System.out.println("destroy");
}
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("afterPropertiesSet");
}
public void init1() {
System.out.println("init1");
}
public void destroy1() {
System.out.println("destroy1");
}
}
Test.java
package com;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
// ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
// BeanLife bl = (BeanLife)ctx.getBean("BeanLife");
// bl.show();
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
BeanLife bl = (BeanLife)ctx.getBean("BeanLife");
bl.show();
ctx.close();//关闭的方法在实现类里面，不再容器里面
}
}
Beans.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<bean id="BeanLife" class="com.BeanLife" init-method="init1" destroy-method="destroy1">
<property name="name" value="ZhangSan"></property>
</bean>
</beans>
运行结果
使用注解方式配置
和上面相比，只是Bean.xml文件里面bean属性删掉，换成了注解形式，并且在BeanFactory里面加上了部分注解
项目结构
BeanLife
package com;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
//实现接口
@Component("BeanLife")
public class BeanLife implements ApplicationContextAware, InitializingBean, DisposableBean{
private ApplicationContext ctx;
private String name;
public void setName(String name) {
this.name = name;
System.out.println("setName属性的赋值");
}
public BeanLife() {
System.out.println("BeanLife的无参构造方法");
}
public void show() {
System.out.println(name);
}
@Override
public void setApplicationContext(ApplicationContext arg0) throws BeansException {
ctx = arg0;//让自己的类可以用传来的ApplicationContext参数
System.out.println("applicationAware");
}
@Override
public void destroy() throws Exception {
System.out.println("destroy");
}
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("afterPropertiesSet");
}
@PostConstruct
public void init1() {
System.out.println("init1");
}
@PreDestroy
public void destroy1() {
System.out.println("destroy1");
}
}
Beans.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<context:annotation-config />
<context:component-scan base-package="com">
</context:component-scan>
</beans>
Bean的作用域
配置singleton属性
