【spring框架】spring中集合的注入

集合注入(很少用)
有的时候我们会使用别人提供我们的类，它里面如果有集合的话，在这个时候我们需要把想注的东西注入进去。


通过<list/>、<set/>、<map/>及<props/>元素可以定义和设置与Java Collection类型对应List、Set、Map及Properties的值。
实现：

<bean id="moreComplexObject" class="example.ComplexObject">
  <!-- results in a setAdminEmails(java.util.Properties) call -->
  <property name="adminEmails">
    <props>
        <prop key="administrator">[e-mail]</prop>
        <prop key="support">[e-mail]</prop>
        <prop key="development">[e-mail]</prop>
    </props>
  </property>
  <!-- results in a setSomeList(java.util.List) call -->
  <property name="someList">
    <list>
        <value>a list element followed by a reference</value>
        <ref bean="myDataSource" />
    </list>
  </property>
  <!-- results in a setSomeMap(java.util.Map) call -->
  <property name="someMap">
    <map>
        <entry>
            <key>
                <value>an entry</value>
            </key>
            <value>just some string</value>
        </entry>
        <entry>
            <key>
                <value>a ref</value>
            </key>
            <ref bean="myDataSource" />
        </entry>
    </map>
  </property>
  <!-- results in a setSomeSet(java.util.Set) call -->
  <property name="someSet">
    <set>
        <value>just some string</value>
        <ref bean="myDataSource" />
    </set>
  </property>
</bean>

实例测试:

UserDaoImpl.java:

package cn.edu.hpu.dao.Impl;


import java.util.List;
import java.util.Map;
import java.util.Set;


import cn.edu.hpu.dao.UserDao;
import cn.edu.hpu.model.User;


public class UserDaoImpl implements UserDao{
  private Set<String> sets;
  private List<String> lists;
  private Map<String,String> maps;


  public Set<String> getSets() {
    return sets;
  }

  public void setSets(Set<String> sets) {
    this.sets = sets;
  }

  public List<String> getLists() {
    return lists;
  }


  public void setLists(List<String> lists) {
    this.lists = lists;
  }

  public Map<String, String> getMaps() {
    return maps;
  }

  public void setMaps(Map<String, String> maps) {
    this.maps = maps;
  }

  public void save(User u) {
      System.out.println("add success!!");    
  }

        @Override
  public String toString() {
        return "sets size:"+sets.size()+"| lists size:"+lists.size()+"| maps size:"+maps.size()+".";
  }


}

然后在beans.xml中配置:

<?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-2.5.xsd">


  <bean id="u" class="cn.edu.hpu.dao.Impl.UserDaoImpl">
     <property name="sets">
      <set>
         <value>1</value>
         <value>2</value>
      </set>
     </property>
      <property name="lists">
      <list>
         <value>1</value>
         <value>2</value>
         <value>3</value>
      </list>
     </property>
     <property name="maps">
      <map>
        <entry key="1" value="1"></entry>
        <entry key="2" value="2"></entry>
        <entry key="3" value="3"></entry>
        <entry key="4" value="4"></entry>
      </map>
     </property>
  </bean>
  
  <bean id="userService" class="cn.edu.hpu.service.UserService" >
     <constructor-arg>
      <ref bean="u"/>
     </constructor-arg>
  </bean>
  
</beans>

spring会把这些值读取来，设到我们那些属性中去。

测试:(在UserDaoImpl中改写了toString方法，这里直接打印UserDao对象即可)

@Test
public void testAdd() throws Exception{
  BeanFactory ctx=new ClassPathXmlApplicationContext("beans.xml");


  UserDao uDao=(UserDao)ctx.getBean("u");
  System.out.println(uDao);
}

结果:

sets size:2| lists size:3| maps size:4.

可以看到已经将各种集合注入。