Spring的SpEL的屬性注入

Spring的SpEL的屬性注入
SpEL：Spring Expression Language，Spring 的表達式語言。

1、注入一般屬性

#{SpEL}

大括號當中可以執行一些計算，調用其他類的方法

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:p="http://www.springframework.org/schema/p"
	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">
	<!-- Spring的屬性注入的方式 -->
	<!-- 構造方法的方式 -->
	<!-- set方法方式符注入 -->
	<!-- SpEL的屬性注入 -->
	<bean id="car2" class="com.itzheng.spring.demo4.Car2">
		<property name="name" value="#{'拖拉機' }"></property>
		<property name="price" value="#{30000}"></property>
	</bean>
</beans>

package com.itzheng.spring.demo4;

/*
 * set方法的屬性注入
 */
public class Car2 {
	private String name;
	private Double price;
	public void setName(String name) {
		this.name = name;
	}
	public void setPrice(Double price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Car2 [name=" + name + ", price=" + price + "]";
	}
}

@Test
	public void demo5() {
		// 創建工程
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
		// 獲得到對應XML當中的對象
		// 獲得到對應XML當中的對象
		Car2 car2 = (Car2) applicationContext.getBean("car2");
		System.out.println(car2);
	}

2、注入對象

（1）直接注入

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:p="http://www.springframework.org/schema/p"
	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">
	<!-- Spring的屬性注入的方式 -->
	<!-- 構造方法的方式 -->
	<!-- SpEL的屬性注入 -->
	<bean id="car2" class="com.itzheng.spring.demo4.Car2">
		<property name="name" value="#{'拖拉機' }"></property>
		<property name="price" value="#{30000}"></property>
	</bean>
	<bean id="employee" class="com.itzheng.spring.demo4.Employee">
		<property name="name" value="#{'武九' }"></property>
		<property name="car2" value="#{car2}"></property>
	</bean>
</beans>

package com.itzheng.spring.demo4;
public class Employee {
	private String name;
	private Car2 car2;
	public void setName(String name) {
		this.name = name;
	}
	public void setCar2(Car2 car2) {
		this.car2 = car2;
	}
	@Override
	public String toString() {
		return "Employee [name=" + name + ", car2=" + car2 + "]";
	}
}

@Test
	public void demo5() {
		// 創建工程
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
		// 獲得到對應XML當中的對象
		// 獲得到對應XML當中的對象
		Car2 car2 = (Car2) applicationContext.getBean("car2");
		System.out.println(car2);
	}

（2）通過方法獲得值，注入到另外一個對象的屬性

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:p="http://www.springframework.org/schema/p"
	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">
	<!-- Spring的屬性注入的方式 -->
	<!-- 構造方法的方式 -->
	<!-- SpEL的屬性注入 -->
	<bean id="carInfo" class="com.itzheng.spring.demo4.CarInfo">
	
	</bean>
	
	<bean id="car2" class="com.itzheng.spring.demo4.Car2">

		<property name="name" value="#{carInfo.name}"></property>
		<property name="price" value="#{carInfo.calculatorPrice()}"></property>

	</bean>
	
</beans>

package com.itzheng.spring.demo4;
public class CarInfo {
	private String name;
	public String getName() {
		return "摩托車";
	}
	public Double calculatorPrice() {
		return Math.random() * 3000;
	}
}

package com.itzheng.spring.demo4;
public class CarInfo {
	private String name;
	public String getName() {
		return "摩托車";
	}
	public Double calculatorPrice() {
		return Math.random() * 3000;
	}
}

測試

測試