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Spring框架学习笔记(5)——自动装配
1、通过bean标签的autowire属性可以实现bean属性的自动装配。
创建一个新的Spring配置文件beans-autowire.xml,这里我们配置了3个bean,Address、Car、People,其中People自动装配了另外两个bean,使用的是bean标签的autowire属性,这个例子里如果将car改为car2打印出来的Person bean 的Car属性为null,即byName根据bean的setter风格进行自动装配有就装没有就不装。而使用byType的话如果配置有两个类型相同的bean就会报错。
<?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-3.1.xsd"> <bean id="address" class="com.broadtext.beans.autowire.Address"> <property name="city" value="Hefei"></property> <property name="street" value="Feixilu"></property> </bean> <bean id="car" class="com.broadtext.beans.autowire.Car"> <property name="brand" value="Audi"></property> <property name="price" value="300000"></property> </bean> <!-- 可以使用autowire属性指定自动装配的方式, byName根据bean的setter风格进行自动装配有就装没有就不装, byType根据bean的类型和bean的属性的类型进行自动装配,一个以上类型匹配则抛异常 --> <bean id="person" class="com.broadtext.beans.autowire.Person" autowire="byName" p:name="hj"></bean> </beans>
2、Address.java、Car.java、People.java、Main.java
Address.java
package com.broadtext.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
package com.broadtext.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 construstor"); } }
People.java
package com.broadtext.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
package com.broadtext.beans.autowire; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { /** * <p>Description: 测试bean的自动装配</p> */ public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-autowire.xml"); Person person = (Person) ctx.getBean("person"); System.out.println(person); } }
Spring框架学习笔记(5)——自动装配
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