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Spring三种配置注入方式

1.基于XML注入

Car类

public class Car {		double price;		String brand;		public double getPrice() {			return price;		}		public void setPrice(double price) {			this.price = price;		}		public String getBrand() {			return brand;		}		public void setBrand(String brand) {			this.brand = brand;		}		}

定义了价格和品牌

MyCar类

public class MyCar {		Car car;		public Car getCar() {			return car;		}		public void setCar(Car car) {			this.car = car;		}		@Override		public String toString() {			// TODO Auto-generated method stub			return car.price+"   "+car.brand;		}				}

采用属性注入，所以对于注入的类或者变量需要提供setter方法

XML配置文件：

启动类：

import org.springframework.beans.factory.BeanFactory;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.core.io.Resource;import org.springframework.core.io.support.PathMatchingResourcePatternResolver;import org.springframework.core.io.support.ResourcePatternResolver;public class Test {	/**	 * @param args	 */	public static void main(String[] args) {		ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();		Resource resource = resolver.getResource("classpath:com/testa/beans.xml");		BeanFactory beanFactory = new XmlBeanFactory(resource);		MyCar myCar = beanFactory.getBean("mycar", MyCar.class);		System.out.println(myCar.toString());	}}

2.注解配置

首先Car类

import org.springframework.stereotype.Component;@Component("car")public class Car {		double price;		String brand;		public Car() {			this.brand = "bmw";			this.price=55;		}		public double getPrice() {			return price;		}		public void setPrice(double price) {			this.price = price;		}		public String getBrand() {			return brand;		}		public void setBrand(String brand) {			this.brand = brand;		}		}

@component （把普通pojo实例化到spring容器中，相当于配置文件中的<bean id="" class=""/>）

myCar类

import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;@Component("mycar")public class MyCar {		@Autowired		Car car;					public Car getCar() {			return car;		}		public void setCar(Car car) {			this.car = car;		}		@Override		public String toString() {			// TODO Auto-generated method stub			return  car.brand+"  "+car.price;		}		}

@Autowired 注释，它可以对类成员变量、方法及构造函数进行标注，完成自动装配的工作,此处可以将Car实例注入进MyCar

此时还需要配置扫描包

启动类

import org.springframework.context.support.AbstractApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test {	/**	 * @param args	 */	public static void main(String[] args) {		 AbstractApplicationContext context = new ClassPathXmlApplicationContext("com/testb/beans.xml");		 MyCar myCar = (MyCar) context.getBean("mycar");		 System.out.println(myCar.toString());		 	}}

3.基于Java类进行配置

Car类：

public class Car {			double price;	String brand;	public Car() {		this.price=333;		this.brand="bmw";	}	public double getPrice() {		return price;	}	public void setPrice(double price) {		this.price = price;	}	public String getBrand() {		return brand;	}	public void setBrand(String brand) {		this.brand = brand;	}	}

配置类：

import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class Config {	@Bean	public Car getCar() {		return new Car();	}	@Bean	public MyCar getMyCar(){		return new MyCar();	}	}

指定配置信息的类上加上 @Configuration 注解，以明确指出该类是 Bean 配置的信息源。并且 Spring 对标注

Configuration 的类有如下要求：

配置类不能是 final 的；配置类不能是本地化的，亦即不能将配置类定义在其他类的方法内部；配置类必须有一个无参构造函数。AnnotationConfigApplicationContext 将配置类中标注了 @Bean 的方法的返回值识别为 Spring Bean，并注册到容器中，受 IoC 容器管理。

MyCar类：

import org.springframework.beans.factory.annotation.Autowired;public class MyCar {	@Autowired	Car car;	@Override	public String toString() {		// TODO Auto-generated method stub		return car.price+"  "+car.brand;	}				}

将Car进行注入

启动类：

import org.springframework.context.ApplicationContext;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class Test {	/**	 * @param args	 */	public static void main(String[] args) {		ApplicationContext context = new AnnotationConfigApplicationContext(Config.class);		MyCar myCar = context.getBean(MyCar.class);		System.out.println(myCar.toString());	}}

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