Spring SPEL 表达式

SPEL 详细说明：

http://docs.spring.io/spring/docs/4.3.0.BUILD-SNAPSHOT/spring-framework-reference/htmlsingle/#expressions

例子：

Address.java

package com.spring.spel;

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

	public String getCity() {
		return city;
	}

	public void setCity(String city) {
		this.city = city;
	}

	public String getStreet() {
		return street;
	}

	public void setStreet(String street) {
		this.street = street;
	}

	@Override
	public String toString() {
		return "Address [city=" + city + ", street=" + street + "]";
	}

}

 Car.java

package com.spring.spel;

public class Car {
	private String brand;
	private double price;
	private double tyrePerimeter;
	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
	public double getTyrePerimeter() {
		return tyrePerimeter;
	}
	public void setTyrePerimeter(double tyrePerimeter) {
		this.tyrePerimeter = tyrePerimeter;
	}
	@Override
	public String toString() {
		return "Car [brand=" + brand + ", price=" + price + ", tyrePerimeter=" + tyrePerimeter + "]";
	}
}

 Person.java

package com.spring.spel;

public class Person {
	private String name;
	private Car car;
	//引用ddress bean的city属性
	private String city;
	//根据car的price 确定info: car的price > 300000
	private String info;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Car getCar() {
		return car;
	}
	public void setCar(Car car) {
		this.car = car;
	}
	public String getCity() {
		return city;
	}
	public void setCity(String city) {
		this.city = city;
	}
	public String getInfo() {
		return info;
	}
	public void setInfo(String info) {
		this.info = info;
	}
	@Override
	public String toString() {
		return "Person [name=" + name + ", car=" + car + ", city=" + city + ", info=" + info + "]";
	}
	
	
}

 XML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"
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 使用SpEL 来为属性赋值 -->
<bean id="address" class="com.spring.spel.Address" p:city="#{'SH'}" p:street="lianHangRoad" />
<!-- 使用SpEL 来引用类的静态属性 -->
<bean id="car" class="com.spring.spel.Car" p:brand="AUDI" p:price="#{200000}" p:tyrePerimeter="#{T(java.lang.Math).PI*2*80}" > </bean>
<!-- 1. 使用SpEL 来应用其他Bean的属性—>p:city.  2.  使用SpEL 来应用其他Bean->p:car 3. 使用SpEL 运算算术符 -->
<bean id="person" class="com.spring.spel.Person"
 	 p:city="#{address.city}"   
 	 p:car="#{car}" 
 	 p:name="#{'Matt'}" 
 	 p:info="#{car.price > 300000 ? '白领' : '蓝领'}" />

</beans>

 Main.java

package com.spring.spel;

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

public class Main {

	public static void main(String[] args) {
		ApplicationContext ext = new ClassPathXmlApplicationContext("spEL.xml");
		Address address = (Address) ext.getBean("address");
		System.out.println(address);
		
		Car car = (Car) ext.getBean("car");
		System.out.println(car);
		
		Person person = (Person) ext.getBean("person");
		System.out.println(person);
	}

}

 运行结果：

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Address [city=SH, street=lianHangRoad]
Car [brand=AUDI, price=200000.0, tyrePerimeter=502.6548245743669]
Person [name=Matt, car=Car [brand=AUDI, price=200000.0, tyrePerimeter=502.6548245743669], city=SH, info=蓝领]