Spring之Autowire自动装配

1.新建实体类

public class Car {
    private String brand;
    private double price;
    public String getBrand() {
        return brand;
    }
    public void setBrand(String brand) {
        this.brand = brand;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Car [brand=" + brand + ", price=" + price + "]";
    }
}

public class Address {
    
    private String city;
    private String street;
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getStreet() {
        return street;
    }
    public void setStreet(String street) {
        this.street = street;
    }
    @Override
    public String toString() {
        return "Address [city=" + city + ", street=" + street + "]";
    }
}

public class Person {
    
    private String name;
    private Car car;
    private Address address;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Car getCar() {
        return car;
    }
    public void setCar(Car car) {
        this.car = car;
    }
    public Address getAddress() {
        return address;
    }
    public void setAddress(Address address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", car=" + car + ", address=" + address
                + "]";
    }
}

2.XML文件

<?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="address" class="com.auguigu.spring.beans.autowire.Address">
        <property name="city" value="BeiJing"></property>
        <property name="street" value="HuiLongGuan"></property>
    </bean>
    
    <bean id="car" class="com.auguigu.spring.beans.autowire.Car">
        <property name="brand" value="Audi"></property>
        <property name="price" value="30000"></property>
    </bean>
    <bean id="person" class="com.auguigu.spring.beans.autowire.Person" autowire="byName">
        <property name="name" value="Tom"></property>
    </bean>
</beans>

3.测试类

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

public class Main {
    
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-autowire.xml");
        Person p = (Person) ctx.getBean("person");
        System.out.println(p);
    }
}

byName根据bean的id和当前setter属性名自动装配

byType 根据bean的类型和当前bean的属性的类型自动装配，但是，若IOC容器有一个以上的类型匹配的bean，则抛出异常