Spring入门第三课
注入的方式：
1.属性注入（setter方法）
2.构造方法注入
3.p名称空间注入
复杂属性的注入：
1.对象的注入
2.数组注入&List集合注入&Map注入&Properties注入
属性注入
属性注入就是通过setter方法注入Bean的属性值或依赖的对象。
属性植入使用<property>元素，使用name属性指定Bean的属性名称，value属性或者<value>子节点指定属性值
属性注入是实际应用中最常用的注入方式。
构造方法注入
通过构造方法注入Bean的属性值或依赖的对象，它保证了Bean实例化以后就可以使用。
构造器注入在<constructor-arg>元素里申明属性，<constructor-arg>中没有name属性
package logan.spring.study;
public class Car {
private String brand;
private String corp;
private int price;
private int maxspeed;
public Car(String brand, String corp, int price) {
super();
this.brand = brand;
this.corp = corp;
this.price = price;
}
@Override
public String toString() {
return "Car [brand=" + brand + ", corp=" + corp + ", price=" + price + ", maxspeed=" + maxspeed + "]";
}
}
package logan.spring.study; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) {
// TODO Auto-generated method stub
//1.创建Spring的IOC容器对象
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); Car car = ctx.getBean(Car.class);
System.out.println(car); } }
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi"></constructor-arg>
<constructor-arg value="Shanghai"></constructor-arg>
<constructor-arg value="3000000"></constructor-arg>
</bean> </beans>
还可以这样配置,根据index来安排属性赋值的序号，第一个为0.
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2"></constructor-arg>
</bean> </beans>
当如下配置时，会不合逻辑，因为Bean里面有两个构造函数，构造函数的参数不一样，所以这个时候根据序号已经不能满足指定使用哪个构造函数还构造Bean的实例，所以会出现实例化出错。
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma"></constructor-arg>
<constructor-arg value="Shanghai"></constructor-arg>
<constructor-arg value="240"></constructor-arg>
</bean> </beans>
package logan.spring.study; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) {
// TODO Auto-generated method stub
//1.创建Spring的IOC容器对象
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); Car car = (Car) ctx.getBean("car");
System.out.println(car);
Car car2 = (Car) ctx.getBean("car2");
System.out.println(car2); } }
这个是得到的结果
五月 18, 2017 10:00:14 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3eb07fd3: startup date [Thu May 18 22:00:14 CST 2017]; root of context hierarchy
五月 18, 2017 10:00:14 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
HelloWorld's Constructor...
HelloWorld's Constructor...
Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]
Car [brand=Baoma, corp=Shanghai, price=240.0, maxspeed=0]
可以看到我们的本意是想把240赋值到最大速度上，但是事实上240没有赋值到maxSpeed上而是赋值到价格上。
这个时候的解决方案是根据type来看使用哪一个构造函数。
如下修改配置文件可以正确赋值
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg value="Shanghai" type="java.lang.String"></constructor-arg>
<constructor-arg value="240" type="int"></constructor-arg>
</bean> </beans>
得到如下结果：使用构造器注入属性值时可以指定参数的位置和参数的类型！以区分重载的构造器
五月 18, 2017 10:04:26 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3eb07fd3: startup date [Thu May 18 22:04:26 CST 2017]; root of context hierarchy
五月 18, 2017 10:04:26 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
HelloWorld's Constructor...
HelloWorld's Constructor...
Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]
Car [brand=Baoma, corp=Shanghai, price=0.0, maxspeed=240]
还可以如下配置，使用子节点给属性赋值
<?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">
<!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg value="Shanghai" type="java.lang.String"></constructor-arg>
<constructor-arg type="int">
<value>250</value>
</constructor-arg>
</bean> </beans>
字面值：可以使用字符串表示的值，可以通过<value>元素标签或者value属性进行注入。
基本数据类型及其封装类，String等类型都可以采取字面值注入的方式
若字面值中包含特殊字符，可以使用<![CDATA[]]>把字面值包裹起来。
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg type="java.lang.String">
<value><![CDATA[<Shanghai>]]></value>
</constructor-arg>
<constructor-arg type="int">
<value>250</value>
</constructor-arg>
</bean> </beans>
下面看Bean相互引用
组成应用程序的Bean经常需要相互协作以完成应用程序的功能。要使Bean能够相互访问，就必须在Bean配置文件中指定对Bean的引用。
在Bean的配置文件中，可以通过<ref>元素或者ref属性为Bean的属性或者构造器参数指定对Bean的引用。
也可以在属性或者构造器里包含Bean的声明，这样的Bean称为内部Bean。
package logan.spring.study;
public class Person {
private String name;
private int age;
private 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;
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", car=" + car + "]";
}
}
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg type="java.lang.String">
<value><![CDATA[<Shanghai>]]></value>
</constructor-arg>
<constructor-arg type="int">
<value>250</value>
</constructor-arg>
</bean> <bean id="person" class="logan.spring.study.Person">
<property name="name" value="Tom"></property>
<property name="age" value="24"></property>
<property name="car" ref="car2"></property>
</bean> </beans>
package logan.spring.study; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) {
// TODO Auto-generated method stub
//1.创建Spring的IOC容器对象
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); Car car = (Car) ctx.getBean("car");
System.out.println(car);
Car car2 = (Car) ctx.getBean("car2");
System.out.println(car2);
Person person = ctx.getBean(Person.class);
System.out.println(person);
} }
下面是输出结果
五月 18, 2017 10:21:47 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3eb07fd3: startup date [Thu May 18 22:21:47 CST 2017]; root of context hierarchy
五月 18, 2017 10:21:47 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
HelloWorld's Constructor...
HelloWorld's Constructor...
Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]
Car [brand=Baoma, corp=<Shanghai>, price=0.0, maxspeed=250]
Person [name=Tom, age=24, car=Car [brand=Baoma, corp=<Shanghai>, price=0.0, maxspeed=250]]
看内部Bean配置方法：
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg type="java.lang.String">
<value><![CDATA[<Shanghai>]]></value>
</constructor-arg>
<constructor-arg type="int">
<value>250</value>
</constructor-arg>
</bean> <bean id="person" class="logan.spring.study.Person">
<property name="name" value="Tom"></property>
<property name="age" value="24"></property>
<property name="car">
<bean class="logan.spring.study.Car">
<constructor-arg value="Ford"></constructor-arg>
<constructor-arg value="Changan"></constructor-arg>
<constructor-arg value="20000000" type="double"></constructor-arg>
</bean>
</property>
</bean> </beans>
运行结果
五月 18, 2017 10:36:26 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3eb07fd3: startup date [Thu May 18 22:36:26 CST 2017]; root of context hierarchy
五月 18, 2017 10:36:26 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
HelloWorld's Constructor...
HelloWorld's Constructor...
Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]
Car [brand=Baoma, corp=<Shanghai>, price=0.0, maxspeed=250]
Person [name=Tom, age=24, car=Car [brand=Ford, corp=Changan, price=2.0E7, maxspeed=0]]
注意：内部Bean不能被外部Bean引用。
还可以如下配置，根据构造方法来实例化Bean
<?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"> <!-- 通过构造方法来配置Bean的属性 -->
<bean id="car" class="logan.spring.study.Car">
<constructor-arg value="Audi" index="0"></constructor-arg>
<constructor-arg value="Shanghai" index="1"></constructor-arg>
<constructor-arg value="3000000" index="2" type="double"></constructor-arg>
</bean>
<bean id="car2" class="logan.spring.study.Car">
<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>
<constructor-arg type="java.lang.String">
<value><![CDATA[<Shanghai>]]></value>
</constructor-arg>
<constructor-arg type="int">
<value>250</value>
</constructor-arg>
</bean> <bean id="person" class="logan.spring.study.Person">
<property name="name" value="Tom"></property>
<property name="age" value="24"></property>
<property name="car">
<bean class="logan.spring.study.Car">
<constructor-arg value="Ford"></constructor-arg>
<constructor-arg value="Changan"></constructor-arg>
<constructor-arg value="20000000" type="double"></constructor-arg>
</bean>
</property>
</bean> <bean id="person2" class="logan.spring.study.Person">
<constructor-arg value="Jerry"></constructor-arg>
<constructor-arg value="25"></constructor-arg>
<constructor-arg ref="car"></constructor-arg>
</bean> </beans>
package logan.spring.study;
public class Person {
private String name;
private int age;
private 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;
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", car=" + car + "]";
}
public Person() {
// TODO Auto-generated constructor stub
}
public Person(String name, int age, Car car) {
super();
this.name = name;
this.age = age;
this.car = car;
}
}
package logan.spring.study; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) {
// TODO Auto-generated method stub
//1.创建Spring的IOC容器对象
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); Car car = (Car) ctx.getBean("car");
System.out.println(car);
Car car2 = (Car) ctx.getBean("car2");
System.out.println(car2);
Person person = (Person) ctx.getBean("person2");
System.out.println(person);
} }
输出结果如下：
五月 18, 2017 10:43:51 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3eb07fd3: startup date [Thu May 18 22:43:51 CST 2017]; root of context hierarchy
五月 18, 2017 10:43:51 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
HelloWorld's Constructor...
HelloWorld's Constructor...
Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]
Car [brand=Baoma, corp=<Shanghai>, price=0.0, maxspeed=250]
Person [name=Jerry, age=25, car=Car [brand=Audi, corp=Shanghai, price=3000000.0, maxspeed=0]]
2.数组注入&List集合注入&Map注入&Properties注入
applicationContext.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"> <!-- 配置bean
class:bean的全类名，通过反射的方式在IOC容器中创建bean，所以要求Bean中必须有无参的构造函数
id:表示容器的bean，id唯一 -->
<bean id="persionService" class="com.study.entity.Persion">
<property name="name" value="xiaozhang"></property>
<property name="age" value="29"></property>
<property name="car" ref="car2"></property>
</bean> <bean id="persionService1" class="com.study.entity.Persion">
<property name="name" value="xiaozhang"></property>
<property name="age" value="29"></property>
<property name="car">
<bean class="com.study.entity.Car">
<constructor-arg value="Ford"></constructor-arg>
<constructor-arg value="Changan"></constructor-arg>
<constructor-arg value="2000000" type="int"></constructor-arg>
</bean>
</property>
</bean> <bean id="persionService3" class="com.study.entity.Persion">
<constructor-arg value="Jerry"></constructor-arg>
<constructor-arg value="26"></constructor-arg>
<constructor-arg ref="car"></constructor-arg>
</bean>
<bean id="persionService4" class="com.study.entity.Persion">
<property name="name" value="Tom"></property>
<property name="age" value="27"></property>
<property name="car" ref="car"></property>
<property name="wayToCompany">
<list>
<value>walk</value>
<value>bike</value>
<value>subway</value>
<value>walk</value>
</list>
</property>
<property name="money">
<map>
<entry key="三月" value="10000"></entry>
<entry key="四月" value="10001"></entry>
<entry key="五月" value="10002"></entry>
<entry key="六月" value="10003"></entry>
</map>
</property>
</bean>
<bean id="car" class="com.study.entity.Car">
<constructor-arg value="Audi" index="1"></constructor-arg>
<constructor-arg value="Shanghai" index="0"></constructor-arg>
<constructor-arg value="3000000" index="2"></constructor-arg>
</bean> <bean id="car2" class="com.study.entity.Car">
<constructor-arg index="1">
<value><![CDATA[<Shanghai>]]></value>
</constructor-arg>
<constructor-arg value="Shanghai" index="0"></constructor-arg>
<constructor-arg value="240" index="2" type="double"></constructor-arg>
</bean> </beans>
Persion.java
package com.study.entity; import java.util.List;
import java.util.Map; public class Persion { private String name;
private Integer age;
private Car car;
private List wayToCompany;
private Map money;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
} public List getWayToCompany() {
return wayToCompany;
}
public void setWayToCompany(List wayToCompany) {
this.wayToCompany = wayToCompany;
}
public Map getMoney() {
return money;
}
public void setMoney(Map money) {
this.money = money;
} public Persion(String name, Integer age, Car car) {
super();
this.name = name;
this.age = age;
this.car = car;
}
public Persion() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Persion [name=" + name + ", age=" + age + ", car=" + car + ", wayToCompany=" + wayToCompany + ", money="
+ money + "]";
} }
TestPersion.java
package com.study.entity; import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class TestPersion { public static void main(String[] args) {
// TODO Auto-generated method stub
Persion p1 = new Persion();
p1.setName("xiaoming");
System.out.println(p1.getName()); ApplicationContext ext = new ClassPathXmlApplicationContext("applicationContext.xml"); Persion p2 = (Persion) ext.getBean("persionService");
System.out.println(p2.toString()); Persion p3 = (Persion) ext.getBean("persionService1");
System.out.println(p3.toString()); Persion p4 = (Persion) ext.getBean("persionService3");
System.out.println(p4.toString()); Persion p5 = (Persion) ext.getBean("persionService4");
System.out.println(p5.toString());
} }
输出结果：
xiaoming
三月 06, 2020 10:12:14 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@4d405ef7: startup date [Fri Mar 06 22:12:14 CST 2020]; root of context hierarchy
三月 06, 2020 10:12:15 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
Persion [name=xiaozhang, age=29, car=Car [brand=Shanghai, corp=<Shanghai>, price=0, maxSpeed=240.0], wayToCompany=null, money=null]
Persion [name=xiaozhang, age=29, car=Car [brand=Ford, corp=Changan, price=2000000, maxSpeed=0.0], wayToCompany=null, money=null]
Persion [name=Jerry, age=26, car=Car [brand=Shanghai, corp=Audi, price=3000000, maxSpeed=0.0], wayToCompany=null, money=null]
Persion [name=Tom, age=27, car=Car [brand=Shanghai, corp=Audi, price=3000000, maxSpeed=0.0], wayToCompany=[walk, bike, subway, walk], money={三月=10000, 四月=10001, 五月=10002, 六月=10003}]
大家可以看到，数组和List集合的注入方式是一样的。Map由于是以键值对的形式存储的，所以注入稍微有一点区别。
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