Spring 设计的核心是 org.springframework.beans 包，它的设计目标是与 JavaBean 组件一起使用。这个包通常不是由用户直接使用，而是由服务器将其用作其他多数功能的底层中介。下一个最高级抽象是 BeanFactory 接口，它是工厂设计模式的实现，允许通过名称创建和检索对象。BeanFactory 也可以管理对象之间的关系。
一、对象创建
1.1、创建一个user对象
User.java
package com.testfan.spring.ioc;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class User {
private String name;
private int age;
private Car car;
private List<Car> carList;
private Set<Car> setlist;
private Map<String, Object> map;
public Map<String, Object> getMap() {
return map;
}
public void setMap(Map<String, Object> map) {
this.map = map;
}
public Set<Car> getSetlist() {
return setlist;
}
public void setSetlist(Set<Car> setlist) {
this.setlist = setlist;
}
public List<Car> getCarList() {
return carList;
}
public void setCarList(List<Car> carList) {
this.carList = carList;
}
public User() {
System.out.println(" create ");
}
public void init() {
System.out.println("init---");
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [name=" + name + ", age=" + age + "]";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + age;
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (age != other.age)
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
public static void main(String[] args) {
try {
Class clz= Class.forName("com.testfan.spring.ioc.User");
User object =(User) clz.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
}
}
1.2 BeanFactory 支持两个对象模型。
1.2.2 单态
模型提供了具有特定名称的对象的共享实例，可以在查询时对其进行检索。Singleton 是默认的也是最常用的对象模型。对于无状态服务对象很理想。
xml文件（ioc.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="user" class="com.testfan.spring.ioc.User">
</bean>
</beans>
IocTest.java
package com.testfan.spring.ioc;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class IocTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("ioc.xml");
//byname/id
User user = (User) context.getBean("user");
System.out.println(user);
//bytype
User user2 = context.getBean(User.class);
System.out.println(user2);
System.out.println(user==user2);
}
}
image.png
1.2.3 原型
模型确保每次检索都会创建单独的对象。在每个用户都需要自己的对象时，原型模型最适合。
xml文件（ioc.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="user" class="com.testfan.spring.ioc.User" scope="prototype">
</bean>
</beans>
IocTest.java
package com.testfan.spring.ioc;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class IocTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("ioc.xml");
//byname/id
User user = (User) context.getBean("user");
System.out.println(user);
//bytype
User user2 = context.getBean(User.class);
System.out.println(user2);
System.out.println(user==user2);
}
}
结果：user！=user2
原因：prototype 每次创建新的对象
二、对象赋值
property属性注入
2.1 基本属性
xml文件（ioc.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="user" class="com.testfan.spring.ioc.User" scope="prototype">
<property name="name" value="zhangsan"></property>
<property name="age" value="20"></property>
</bean>
</beans>
2.2 对象关联
ref：引用其他bean对象
property:调用set方法
constructor-arg:调用构造方法
Car.java（创建一个car对象）
package com.testfan.spring.ioc;
import javax.annotation.Resource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component("cartest")
public class Car {
private String name;
private double price;
@Resource(name="user")
private User user2;
public User getUser2() {
return user2;
}
public void setUser2(User user2) {
this.user2 = user2;
}
public Car(String name, double price) {
super();
this.name = name;
this.price = price;
System.out.println(" 我有参数 ");
}
public Car() {
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
@Override
public String toString() {
return "Car [name=" + name + ", price=" + price + "]";
}
}
ioc.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="user" class="com.testfan.spring.ioc.User" scope="prototype">
<!-- 配置注入属性 -->
<property name="name" value="zhangsan"></property>
<property name="age" value="20"></property>
<property name="car" ref="cartest"></property>
</bean>
<bean class="com.testfan.spring.ioc.Car">
<!-- 配置注入属性 -->
<constructor-arg index="0" value="奥拓"></constructor-arg>
<constructor-arg index="1" value="1000"></constructor-arg>
</bean>
</beans>
IocTest.java
//对象关联
System.out.println(user.getCar());
2.2复杂对像管理
List
<list>
<ref bean="bean1"/>
<bean></bean>
</list>
例：
<property name="carList">
<list>
<ref bean="cartest" />
<ref bean="cartest" /> //User拥有多辆车，引用其他bean对象
<bean class="com.testfan.spring.ioc.Car"> //创建一个新的bean
<constructor-arg index="0" value="奥拓"></constructor-arg>
<constructor-arg index="1" value="1000"></constructor-arg>
</bean>
</list>
</property>
set:
set和list最大的区别，setlist会去重
<set>
<ref bean:bean1/>
<bean></bean>
</set>
例：
<property name="setlist">
<set>
<ref bean="cartest" />
<ref bean="cartest" />
<bean class="com.testfan.spring.ioc.Car">
<constructor-arg index="0" value="奥拓"></constructor-arg>
<constructor-arg index="1" value="1000"></constructor-arg>
</bean>
</set>
</property>
Map:
<map>
<entry key:key1 value:value1></entry>
<entry key:key2>
<bean></bean>
</entry>
</map>
例：
<property name="map">
<map>
<entry key="zhangsan" value="111"></entry> //普通的字符串
<entry key="car" value-ref="cartest"></entry> //引用bean对象
<entry key="car2"> //自定义的bean对象
<bean class="com.testfan.spring.ioc.Car">
<constructor-arg index="0" value="奥拓"></constructor-arg>
<constructor-arg index="1" value="1000"></constructor-arg>
</bean>
</entry>
</map>
