Spring三种配置注入方式

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：

<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-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
">

<bean id="car" class="com.testa.Car">
<property name="price" value="22"></property>
<property name="brand" value="bmw"></property>
</bean>

<bean id="mycar" class="com.testa.MyCar">
<property name="car">
<ref bean="car"/>
</property>
</bean>

</beans>

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

<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-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
">
<context:component-scan base-package="com.testb"></context:component-scan>

</beans>

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;

@Configuration
public 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());

}

}