Spring EL hello world实例

1. Spring Beans

package com.yiibai.core;

public class Customer {

	private Item item;

	private String itemName;

}

package com.yiibai.core;

public class Item {

	private String name;

	private int qty;

}

3. Spring EL以XML形式

<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-3.0.xsd">

	<bean id="itemBean" class="com.yiibai.core.Item">
		<property name="name" value="itemA" />
		<property name="qty" value="10" />
	</bean>

	<bean id="customerBean" class="com.yiibai.core.Customer">
		<property name="item" value="#{itemBean}" />
		<property name="itemName" value="#{itemBean.name}" />
	</bean>
	
</beans>

1. #{itemBean} – 注入“itemBean”到“customerBean”Bean 的“item”属性。
2. #{itemBean.name} – 注入“itemBean”的“name”属性到 “customerBean" bean的"itemname”属性。

4. Spring EL以注解形式

package com.yiibai.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("customerBean")
public class Customer {

	@Value("#{itemBean}")
	private Item item;

	@Value("#{itemBean.name}")
	private String itemName;

	//...

}

package com.yiibai.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("itemBean")
public class Item {

	@Value("itemA") //inject String directly
	private String name;

	@Value("10") //inject interger directly
	private int qty;

	public String getName() {
		return name;
	}

	//...
}

<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-3.0.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context-3.0.xsd">

	<context:component-scan base-package="com.yiibai.core" />

</beans>

5. 执行输出

package com.yiibai.core;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App {
	public static void main(String[] args) {
	    ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

	    Customer obj = (Customer) context.getBean("customerBean");
	    System.out.println(obj);
	}
}

输出结果

Customer [item=Item [name=itemA, qty=10], itemName=itemA]