Spring注入方式(2)

3、引用其他bean

　　Bean经常需要相互协作完成应用程序的功能，bean之间必须能够互相访问，就必须在bean配置之间指定对bean的引用，可以通过节点<ref>或者ref来为bean属性指定对bean的引用，也可以在属性或者构造器里包含bean的声明，这样bean称为内部bean。

bean中引用其他bean,其中Car为对象。

 <!-- 通过构造方法配置bean属性 -->
     <bean id="car" class="hello.Car">
     <constructor-arg value="Audi" index="0"></constructor-arg>
     <constructor-arg value="ShangHai" index="1"></constructor-arg>
     <constructor-arg value="300000" type="double" ></constructor-arg>

 </bean>

 <bean id="person" class="hello.Person">
     <property name="name" value = "Tom"></property>
     <property name="age" value = "24"></property>
     <property name="car" ref="car"></property>
 </bean>

内部bean

 <bean id="person" class="hello.Person">
         <property name="name" value = "Tom"></property>
         <property name="age" value = "24"></property>
         <!--
         <property name="car" ref="car"></property>-->

         <!-- 内部bean -->
         <property name="car">
             <!-- 内部bean不能被外部bean使用 -->
             <bean id="car3" class="hello.Car">
                 <constructor-arg value="Ford"></constructor-arg>
                 <constructor-arg value="Changan"></constructor-arg>
                 <constructor-arg value="200000" type="double"></constructor-arg>

             </bean>
         </property>
 </bean>

4、集合属性

在Spring中可以通过<list>、<set>或者<map>来配置集合属性。

通过list配置集合属性

Person.java

 package com.spring;

 import java.util.List;

 public class Person {
     private String name;
     private int age;
     private List<Car> cars;
     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 List<Car> getCars() {
         return cars;
     }
     public void setCars(List<Car> cars) {
         this.cars = cars;
     }
     @Override
     public String toString() {
         return "Person [name=" + name + ", age=" + age + ", cars=" + cars + "]";
     }

 }

Car.java

 package com.spring;

 public class Car {
     private String brand;
     private double price;
     private int maxSpeed;
     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;
     }
     public int getMaxSpeed() {
         return maxSpeed;
     }
     public void setMaxSpeed(int maxSpeed) {
         this.maxSpeed = maxSpeed;
     }
     @Override
     public String toString() {
         return "Car [brand=" + brand + ", price=" + price + ", maxSpeed=" + maxSpeed + "]";
     }

 }

beans-collection.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:util="http://www.springframework.org/schema/util"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">

     <bean id="car1" class="com.spring.Car">
         <property name="brand" value="audi"></property>
         <property name="price" value="400000"></property>
         <property name="maxSpeed" value="240"></property>
     </bean>

     <bean id="car2" class="com.spring.Car">
         <property name="brand" value="baoma"></property>
         <property name="price" value="700000"></property>
         <property name="maxSpeed" value="270"></property>
     </bean>

     <bean id="person" class="com.spring.Person">
         <property name="name" value="Jerry"></property>
         <property name="age" value="41"></property>
         <property name="cars">
             <list>
                 <ref bean="car1" />
                 <ref bean="car2" />
             </list>
         </property>
     </bean>
 </beans>

结果：

通过map配置属性

Person.java

 package com.spring;

 import java.util.Map;

 public class Person {
     private String name;
     private int age;
     private Map<String, Car> carMap;
     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 Map<String, Car> getCarMap() {
         return carMap;
     }
     public void setCarMap(Map<String, Car> carMap) {
         this.carMap = carMap;
     }
     @Override
     public String toString() {
         return "Person [name=" + name + ", age=" + age + ", carMap=" + carMap + "]";
     }
 }

beans-collection

 <?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:util="http://www.springframework.org/schema/util"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">

     <bean id="car1" class="com.spring.Car">
         <property name="brand" value="audi"></property>
         <property name="price" value="400000"></property>
         <property name="maxSpeed" value="240"></property>
     </bean>

     <bean id="car2" class="com.spring.Car">
         <property name="brand" value="baoma"></property>
         <property name="price" value="700000"></property>
         <property name="maxSpeed" value="270"></property>
     </bean>

     <bean id="person" class="com.spring.Person">
         <property name="name" value="Jerry"></property>
         <property name="age" value="41"></property>
         <property name="carMap">
             <map>
                 <entry key="1" value-ref="car1"></entry>
                 <entry key="2" value-ref="car2"></entry>
             </map>
         </property>
     </bean>
 </beans>

结果：

配置Set属性，和配置list一样。

5、p名字空间注入，也需要setter方法。

Student.java

 package com.spring;

 public class Student {
     private String name;
     private String number;

     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getNumber() {
         return number;
     }
     public void setNumber(String number) {
         this.number = number;
     }

     @Override
     public String toString() {
         return "Student [name=" + name + ", number=" + number + "]";
     }

 }

Main.java

 package com.spring;

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

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

beans-p.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="student" class="com.spring.Student" p:name="Merry" p:number="1120141314"></bean>

 </beans>

执行结果

6、property注入

Student.java

 package com.spring;

 import java.util.Properties;

 public class Student {
     private String name;
     private String number;
     private Properties properties;

     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getNumber() {
         return number;
     }
     public void setNumber(String number) {
         this.number = number;
     }
     public Properties getProperties() {
         return properties;
     }
     public void setProperties(Properties properties) {
         this.properties = properties;
     }
     @Override
     public String toString() {
         return "Student [name=" + name + ", number=" + number + ", properties=" + properties + "]";
     }

 }

beans-p.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"
     xmlns:util="http://www.springframework.org/schema/util"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">
     <bean id="student" class="com.spring.Student">
         <property name="name" value="Merry"></property>
         <property name="number" value="1120141213"></property>
         <property name="properties" >
             <props>
                 <prop key="user">root</prop>
                 <prop key="psw">1234</prop>
                 <prop key="jdbcUrl">jdbc:mysql:///test</prop>
                 <prop key="driverClass">com.mysql.jdbc.Driver</prop>
             </props>
         </property>

     </bean>
 </beans>

执行结果

7、c命名空间注入