Spring 自动装配 byType，通过属性的 type 与配置文件中的 beans 进行匹配和连接，匹配成功，注入 bean ，否则，抛出异常
    案例代码：
    Person.java

    1. package com.baklib.custom;
    3. public class Person {
    5.     private String name;
    6.     private int age;
    8.     public String getName() {
    9.         return name;
    10.     }
    12.     public void setName(String name) {
    13.         this.name = name;
    14.     }
    16.     public int getAge() {
    17.         return age;
    18.     }
    20.     public void setAge(int age) {
    21.         this.age = age;
    22.     }
    23. }

    Car.java

    1. package com.baklib.custom;
    3. public class Car {
    5.     private String name;
    6.     private double price;
    8.     public String getName() {
    9.         return name;
    10.     }
    12.     public void setName(String name) {
    13.         this.name = name;
    14.     }
    16.     public double getPrice() {
    17.         return price;
    18.     }
    20.     public void setPrice(double price) {
    21.         this.price = price;
    22.     }
    23. }

    Action.java

    1. package com.baklib.custom;
    3. public class Action {
    5.     private Person person;
    6.     private Car car;
    8.     public Person getPerson() {
    9.         return person;
    10.     }
    12.     public void setPerson(Person person) {
    13.         this.person = person;
    14.     }
    16.     public Car getCar() {
    17.         return car;
    18.     }
    20.     public void setCar(Car car) {
    21.         this.car = car;
    22.     }
    24.     public void buyCar() {
    25.         System.out.println(person.getName()+"今年"+person.getAge()+"岁，花了"
    26.                 +car.getPrice()+"元买了"+car.getName());
    27.     }
    28. }

    MainApp.java

    1. package com.baklib.custom;
    3. import org.springframework.context.ApplicationContext;
    4. import org.springframework.context.support.ClassPathXmlApplicationContext;
    6. public class MainApp {
    8.     public static void main(String[] args) {
    9.         ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
    11.         Action action = (Action) context.getBean("action");
    12.         action.buyCar();
    13.     }
    15. }

    配置文件 Beans.xml

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3.        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    6.     <bean id="action" class="com.baklib.custom.Action" autowire="byType">
    7.     </bean>
    9.     <bean id="person" class="com.baklib.custom.Person">
    10.         <property name="name" value="张三" />
    11.         <property name="age" value="20" />
    12.     </bean>
    14.     <bean id="car" class="com.baklib.custom.Car">
    15.         <property name="name" value="小轿车" />
    16.         <property name="price" value="100000" />
    17.     </bean>
    19. </beans>

    编写完以上代码，就可以运行这个程序，运行结束后，可以在控制台看到下面的信息

    1. 张三今年20岁，花了100000.0元买了小轿车