Java依赖注入方式

Posted 2021-01-04 www

构造方法注入

application.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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">

    <bean id = "Orange" class="com.wzh.fruit.impl.Orange"></bean>
    <bean id = "Apple" class="com.wzh.fruit.impl.Apple"></bean>
    
    <bean id = "personApple" class="com.wzh.person.Person">
        <constructor-arg ref="Apple"></constructor-arg>
    </bean>
    
    <bean id = "personOrange" class="com.wzh.person.Person">
        <constructor-arg ref="Orange"></constructor-arg>
    </bean>

</beans>

Fruit.java

package com.wzh.fruit;

public interface Fruit {
    public String getFruit();
}

Apple.java

package com.wzh.fruit.impl;

import com.wzh.fruit.Fruit;

public class Apple implements Fruit{
    
    public Apple() {
        
    }

    public String getFruit() {
        String apple = "apple";
        return apple;
    }

}

Orange.java

package com.wzh.fruit.impl;

import com.wzh.fruit.Fruit;

public class Orange implements Fruit{
    
    public Orange() {
        
    }

    public String getFruit() {
        String orange = "orange";
        return orange;
    }

}

Person.java

package com.wzh.person;

import java.lang.reflect.Constructor;

import com.wzh.fruit.Fruit;

public class Person {
    
    private Fruit fruit;
    
    public Person(Fruit _fruit) {
        fruit = _fruit;
    }
    
    public void eat() {
        System.out.println("I want eat "+fruit.getFruit());
    }

}

Run.java

package com.wzh.run;

import com.wzh.person.Person;

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


public class Run {
    
    public static void main(String[] args) {
        ApplicationContext ac=new ClassPathXmlApplicationContext("application.xml");
        Person p =(Person)ac.getBean("personOrange");
        p.eat();
    }
    
}