Spring框架bean的配置：SpEL：引用 Bean属性和方法。。。

Posted 2020-08-08

1.SpEL，实现

Person类，其属性如下，其get，set，tostrong方法就不写了

private String name;
private Car car;
private String city;//city属性是引用了Address中city的属性
private String info;//根据car的price属性来确定info，price大于30万，不大于30万

 

car类，其属性如下，set，get，tostring方法就不写了

private String brand;
private double price;
private double tyrePerimeter;//轮胎的周长

 

address类，其属性如下，set，get，tostring方法就不下了

private String city;
private String street;

 

建立spring bean configuration file文件：beans.xml

<!-- spEL的使用#{…} -->
    
    <bean id="address" class="com.atguigu.spring.beans.Address">
        <property name="city" value="#{‘BeiJing‘}"></property>
        <property name="street" value="jianglingjialu"></property>
    </bean>
    
    <bean id="car" class="com.atguigu.spring.beans.Car">
        <property name="brand" value="auti"></property>
        <property name="price" value="345566"></property>
        
        <property name="tyrePerimeter" value="#{T(java.lang.Math).PI * 30}"></property>
    </bean>
    
    <bean id="person" class="com.atguigu.spring.beans.Person">
        <property name="name" value="#{‘panpan‘}"></property>
        <property name="car" value="#{car}"></property>
        <property name="city" value="#{address.city}"></property>
        
        <property name="info" value="#{car.price>300000 ? ‘金领‘ : ‘蓝领‘ }"></property>
    </bean>
    

 

在src目录下的Main类 测试方法；

ApplicationContext app=new ClassPathXmlApplicationContext("beans.xml");

Address address=(Address) app.getBean("address");
System.out.println(address);

Car car=(Car) app.getBean("car");
System.out.println(car);
        
Person person=(Person) app.getBean("person");
System.out.println(person);

----------------------------------------------------------------------------------

2.静态工厂方式，spring的bean的配置方法；

　　建立StaticCarFactory类：

package com.atguigu.spring.beans;

import java.util.HashMap;
import java.util.Map;

public class StaticCarFactory {
    //静态工厂方式，spring的bean的配置方法
    private static Map<String, Car> cars=new HashMap<String, Car>();
    static{
        cars.put("KKK", new Car("changan",423423,432.43));
        cars.put("PPP", new Car("fute",42323,32.43));
    }
    //在xml文件中，可以设置和获取getCar方法
    public static Car getCar(String name){
        return cars.get(name);
    }
}

 

在beans.xml 文件中配置bean；

<!-- 静态工厂方式 -->
<bean id="car1" class="com.atguigu.spring.beans.StaticCarFactory"
    factory-method="getCar">
<constructor-arg value="PPP"></constructor-arg>
</bean>

 

在 Main类 中测试；

ApplicationContext app=new ClassPathXmlApplicationContext("beans.xml");
Car car1=(Car) app.getBean("car1");
System.out.println(car1);

-------------------------------------------------------------------------------------

3.实例工厂的方法，实现bean的配置；

　　建立类:InstanceFactory

package com.atguigu.spring.beans;

import java.util.HashMap;
import java.util.Map;

public class InstanceFactory {
    private Map<String, Car> cars=null;
    
    //实例工厂的方法
    public InstanceFactory() {
        cars=new HashMap<String, Car>();
        
        cars.put("KKK", new Car("luhu", 434233, 43.2));
        cars.put("QQQ", new Car("fute", 656546, 45.4));
    }
    
    public Car getCar(String brand){
        return cars.get(brand);
    }
}

 

在beans.xml 文件中配置bean；

<!-- 实例工厂的方式 -->
<bean id="factory" class="com.atguigu.spring.beans.InstanceFactory"></bean>
    
<bean id="car2" factory-bean="factory" factory-method="getCar">
        <constructor-arg value="QQQ"></constructor-arg>
</bean>

 

在类Main中，测试：

ApplicationContext app=new ClassPathXmlApplicationContext("beans.xml");
Car car2=(Car) app.getBean("car2");
System.out.println(car2);

------------------------------------------------------------------------------------------

 4.FactoryBean的配置方法：继承接口：FactoryBean，泛型为Car;

package com.atguigu.spring.beans;

import org.springframework.beans.factory.FactoryBean;

//FactoryBean的配置方法
public class CarFactoryBean implements FactoryBean<Car>{
    
    private String brand;
    
    public void setBrand(String brand) {
        this.brand = brand;
    }
    
    @Override
    //返回bean的对象，即car
    public Car getObject() throws Exception {
        return new Car(brand, 200000, 1.2);
    }

    @Override
    //返回bean的类型
    public Class<?> getObjectType() {
        return Car.class;
    }

    @Override
    //是不是但实力的
    public boolean isSingleton() {
        return true;
    }
    
}

 

在beans.xml 文件中配置bean；

<!-- FactoryBean的配置方法 -->
<bean id="car3" class="com.atguigu.spring.beans.CarFactoryBean">
        <property name="brand" value="panpan"></property>
</bean>

 

在类Main中，测试：

ApplicationContext app=new ClassPathXmlApplicationContext("beans.xml");
Car car3=(Car) app.getBean("car3");
System.out.println(car3);