Spring学习之Bean的装配多种方法

/**
 * 位置类，用于描述学校的位置信息
 */
class Location{
  private String country;
  private String city;

  // 省略set/get方法

  // 省略toString方法
}

/**
 * 学校信息
 */
public class School {

  // 用于演示基本数据类型的注入
  private String name;
  // 学校位置，依赖于Location对象
  private Location location;
  // 用于演示集合类的注入
  private List<String> teachers;
  private Set<String> buildings;
  private Map<String, String> departments;


  public School() {
    teachers = new ArrayList<>();
    buildings = new HashSet<>();
    departments = new HashMap<>();
  }
  // 用于演示构造器注入
  public School(String name) {
    this();
    this.name = name;
  }

  // 省略set/get方法

  // 省略toString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" 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">

  <!--声明Location bean，并且为其两个属性注入对应的字面值-->
  <bean id="location" class="cn.xuhuanfeng.domain.Location">
    <property name="city" value="china"/>
    <property name="country" value="ShenZhen"/>
  </bean>

  <!--配置School bean，并为其注入对象的属性-->
  <bean id="school" class="cn.xuhuanfeng.domain.School">

    <!--构造器注入 index用于指定所要注入的参数的位置，type用于指定注入的参数的类型-->
    <constructor-arg index="0" type="java.lang.String" value="SZU"/>

    <!--由于location依赖于Location对象，所以这里使用的是ref，用于表示引用另一个bean-->
    <property name="location" ref="location"/>

    <!--注入set内容-->
    <property name="buildings">
      <set>
        <value>Domain A</value>
        <value>Domain B</value>
        <value>Domain C</value>
      </set>
    </property>

    <!--注入list内容-->
    <property name="teachers">
      <list>
        <value>Dr.Wang</value>
        <value>Pro.Chen</value>
        <value>Miss.Wu</value>
      </list>
    </property>

    <!--注入map内容-->
    <property name="departments">
      <map>
        <entry key="cs" value="Dr.ming"/>
        <entry key="se" value="Dr.liu"/>
      </map>
    </property>
  </bean>

</beans>

@Component
public class Location{
  private String country;
  private String city;
}

@Component
public class School {

  @Value("SZU")
  private String name;

  @Autowired // 自动注入
  private Location location;

  // ....
}

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

  <!--开启自动扫描， base-package指定所要扫描的包 --> 
  <context:component-scan base-package="cn.xuhuanfeng.domain" />

</beans>