spring 配置bean的方法及依赖注入发方式

Posted 2020-10-03 mthoutai

Bean 的配置方式：通过全类名（反射）、通过工厂方法（静态工厂方法 & 实例工厂方法）、FactoryBean

这里依据全类名配置bean

<bean id="helloWord" class="com.spring.HelloWord">
 <property name="userName" value="springsss"></property>
</bean>

依赖注入发方式：

属性注入：

applicationContext.xml配置文件为：

<?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">
<!-- 配置bean -->
<bean id="helloWord" class="com.spring.HelloWord">
 <property name="userName" value="springsss"></property>
</bean>
</beans>

package com.spring;
public class HelloWord {
private String userName;
public void setUserName(String userName) {
this.userName = userName;
}
public void hello() {
System.out.println("hello:" + userName);
}
public HelloWord(){
System.out.println("construct!!!!!!!!!!");
}
}

package com.spring;


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


public class Test {
public static void main(String[] args) {
/**
* 创建对象及为对象赋值交给spring完毕
*/
// HelloWord helloWord = new HelloWord();
// helloWord.setUserName("hello");
// helloWord.hello();

//1.创建spring IOC容器
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");


//2从容器中获得Bean
HelloWord helloWord = (HelloWord) ctx.getBean("helloWord");


//3.调用方法
helloWord.hello();

}
}

输出结果为：

construct!!!!!!!!!!
hello:springsss

构造器注入：

applicationContext.xml文件为

<?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">
<!-- 配置bean -->
<bean id="car" class="com.spring.Car">
<constructor-arg value="green"></constructor-arg>
<constructor-arg value="22"></constructor-arg>
</bean>
</beans>

public class Car {
 private String name;
 private String color;
 private int num;
public Car(String color, int num) {
super();
this.color = color;
this.num = num;
}
@Override
public String toString() {
return "Car [name=" + name + ", color=" + color + ", num=" + num + "]";
}


}

package com.spring;


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


public class Test {
public static void main(String[] args) {


//1.创建spring IOC容器
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");


Car car = (Car) ctx.getBean("car");
System.out.println(car.toString());

}
}

输出结果为：

Car [name=null, color=green, num=22]