外部属性文件，SpEL表达式，bean的生命周期

1.导入外部文件

1）编写db.properties配置文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/blog
jdbc.user=root
jdbc.password=root

 2）编写applicationContext.xml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"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<!-- 加载配置文件 -->
	<context:property-placeholder location="classpath:db.properties"/>
	<!-- 初始化c3p0数据源 -->
	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
		<property name="driverClass" value="${jdbc.driver}"/>	
		<property name="jdbcUrl" value="${jdbc.url}"></property>	
		<property name="user" value="${jdbc.user}"></property>	
		<property name="password" value="${jdbc.password}"></property>	
	</bean>
	
</beans>

 3）编写测试代码，自己处理吧

 

2.SpEl表达式

SpEL使用#{}做为定界符，引用其他对象，属性，方法

支持运算符，正则，直接调用静态方法或属性

 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<bean id="address" class="com.hous.spring.Address">
		<property name="city" value="#{'suqian'}"></property>
		<property name="street" value="双河大道"></property>
	</bean>
	
	<bean id="car" class="com.hous.spring.Car">
		<property name="brand" value="aodi"></property>
		<property name="price" value="300000"></property>
		<property name="tyerPerimeter" value="#{T(java.lang.Math).PI*20}"></property>
	</bean>
	
	<bean id="person" class="com.hous.spring.Person">
		<property name="age" value="24"></property>
		<property name="car" value="#{car}"></property>
		<property name="info" value="#{car.price>20000 ? '程序员' : '搬砖的'}"></property>
	</bean>
	
</beans>

 

IoC容器中bean的生命周期

1）通过构造器或工厂方法创建bean实例

2）为bean属性设置值或引用其他bean

3）调用bean的初始化方法

4）使用bean

5）当容器关闭时，调用bean的销毁方法

在bean的声明中设置init-method和destroy-method属性

为bean指定初始化和销毁方法

 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<bean id="address" class="com.hous.spring.Address" init-method="init" destroy-method="destroy">
		<property name="city" value="#{'suqian'}"></property>
		<property name="street" value="双河大道"></property>
	</bean>
	
</beans>

 

package com.hous.spring;

public class Address {
	private String city;
	private String street;

	/**
	 * @return the city
	 */
	public String getCity() {
		return city;
	}

	/**
	 * @param city
	 *            the city to set
	 */
	public void setCity(String city) {
		this.city = city;
	}

	/**
	 * @return the street
	 */
	public String getStreet() {
		return street;
	}

	/**
	 * @param street
	 *            the street to set
	 */
	public void setStreet(String street) {
		this.street = street;
	}
	
	public void init() {
		System.out.println("初始化bean。。。");
	}
	
	public void destroy() {
		System.out.println("销毁bean。。。");
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "Address [city=" + city + ", street=" + street + "]";
	}

}

 

package com.hous.test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
	public static void main(String[] args) {
		//1.创建spring的IoC容器
		ClassPathXmlApplicationContext cxt = new ClassPathXmlApplicationContext("applicationContext.xml");
		
		System.out.println(cxt.getBean("address"));
		
		//关闭容器
		cxt.close();
	}
	
}

 Bean的后置处理器

xml文件中依赖注入

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<bean id="address" class="com.hous.spring.Address" init-method="init" destroy-method="destroy">
		<property name="city" value="#{'suqian'}"></property>
		<property name="street" value="双河大道"></property>
	</bean>
	
	<!-- 
		实现BeanPostProcessor接口，并提供具体方法
		Object postProcessAfterInitialization(Object bean, String beanName) 在init-method之前执行
		Object postProcessBeforeInitialization(Object bean, String beanName) 在init-method之后执行
		
		bean：bean实例本身
		beanName： IOC容器配置bean的名字
		返回值：是返回给用户的bean 注意： 以上方法可以修改返回的bean，甚至返回新的bean
	 -->
	<bean class="com.hous.processor.MyBeanProcessor"></bean>
	
</beans>

 实现BeanPostProcessor接口

package com.hous.processor;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class MyBeanProcessor implements BeanPostProcessor {

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
		System.out.println("postProcessAfterInitialization" + beanName + "," + bean);
		return bean;
	}

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		System.out.println("postProcessAfterInitialization" + beanName + "," + bean);
		return bean;
	}

}