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Bean 自动装配
自动装配
byName
byName 根据 bean 的名字和当前 bean 的 setter 风格的属性名进行自动装配,若有匹配的,则进行自动装配,若没有匹配的,则不装配。
<bean id="address" class="com.test.sping.beans.autowire.Address"
p:city="BeiJing" p:street="HuiLongGuan"></bean>
<bean id="car" class="com.test.sping.beans.autowire.Car"
p:brand="Audi" p:price="300000"></bean>
<!-- 可以使用 autowire 属性指定自动装配的方式 -->
<bean id="person" class="com.test.sping.beans.autowire.Person"
p:name="Tom" autowire="byName"></bean>
byType
byType 根据 bean 的类型和当前 bean 的属性的类型进行自动装配,若 IOC 容器中 1 个以上的类型匹配的 bean,则抛异常。
<bean id="address" class="com.test.sping.beans.autowire.Address"
p:city="BeiJing" p:street="HuiLongGuan"></bean>
<bean id="car" class="com.test.sping.beans.autowire.Car"
p:brand="Audi" p:price="300000"></bean>
<!-- 可以使用 autowire 属性指定自动装配的方式 -->
<bean id="person" class="com.test.sping.beans.autowire.Person"
p:name="Tom" autowire="byType"></bean>
源码
Address.java(com.test.sping.beans.autowire.Address)
package com.test.sping.beans.autowire;
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 + '\'' +
'}';
}
}
Car.java(com.test.sping.beans.autowire.Car)
package com.test.sping.beans.autowire;
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 Car() {
System.out.println("Car's Constructor...");
}
}
Person.java(com.test.sping.beans.autowire.Person)
package com.test.sping.beans.autowire;
public class Person {
private String name;
private Address address;
private Car car;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", address=" + address +
", car=" + car +
'}';
}
}
Main.java(com.test.sping.beans.autowire.Main)
package com.test.sping.beans.autowire;
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 person = (Person) ctx.getBean("person");
System.out.println(person);
}
}
beans-autowire.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"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="address" class="com.test.sping.beans.autowire.Address"
p:city="BeiJing" p:street="HuiLongGuan"></bean>
<bean id="car" class="com.test.sping.beans.autowire.Car"
p:brand="Audi" p:price="300000"></bean>
<!--
可以使用 autowire 属性指定自动装配的方式:
byName 根据 bean 的名字和当前 bean 的 setter 风格的属性名进行自动装配,若有匹配的,则进行自动装配,若没有匹配的,则不装配。
byType 根据 bean 的类型和当前 bean 的属性的类型进行自动装配,若 IOC 容器中 1 个以上的类型匹配的 bean,则抛异常。
-->
<bean id="person" class="com.test.sping.beans.autowire.Person"
p:name="Tom" autowire="byName"></bean>
</beans>