Spring 的四种方式依赖注入

一、Spring 基于构造函数的依赖注入

package com.home.model;public class Teditor {    private Specker specker;    public Teditor(Specker specker){        System.out.println("Inside Teditor constructor.");        this.specker=specker;    }    public void speckeCheck(){        specker.Speckering();    }}public class Specker {    public Specker(){        System.out.println("Inside Specker constructor.");    }    public void Speckering(){        System.out.println("Inside Speckering!");    }}//以下为配置文件<!-- 基于构造函数的依赖注入 -->    <bean id="teditor" class="com.home.model.Teditor">       <constructor-arg ref="specker"></constructor-arg>    </bean>    <bean id="specker" class="com.home.model.Specker"></bean>//测试代码 @RequestMapping(value="/teditor",method=RequestMethod.GET)    public ModelAndView DITEST(){        ModelAndView view=new ModelAndView("/login/hello");        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");        Teditor teditor=(Teditor) context.getBean("teditor");        teditor.speckeCheck();        return view;    }

输出结果：
Inside Specker constructor.
Inside Teditor constructor.
inside into Sparker construstor

二、Spring 基于设值函数的依赖注入

//SparkSystem类public class SparkSystem {    private Sparker sparker;    public void setSparker(Sparker sparker){        System.out.println("SparkSystem===Inside setSpark");        this.sparker=sparker;    }    public Sparker getSparker(){        System.out.println("SparkSystem==Inside get getPark");        return sparker;    }    public void spark(){        sparker.sparkering();    }}//Sparker类package com.home.model;public class Sparker {    public Sparker(){        System.out.println("inside into Sparker construstor");    }    public void sparkering(){        System.out.println("inside in Sparker for sparkering");    }}//配置文件 <!-- Spring 基于设值函数的依赖注入 --> <bean id="sparkSystem" class="com.home.model.SparkSystem">      <property name="sparker" ref="sparker"></property> </bean> <bean id="sparker" class="com.home.model.Sparker"></bean>

三、Spring 注入内部 Beans
正如你所知道的 Java 内部类是在其他类的范围内被定义的，同理，inner beans 是在其他 bean 的范围内定义的 bean。因此在 或 元素内 元素被称为内部bean

package com.home.model;//Computer类public class Computer {    private Message message;    public Computer(){        System.out.println("inside into Computer constructor");    }    public void setMessage(Message message){        System.out.println("inside into setComputer");        this.message=message;    }    public Message getMessage(){        System.out.println("inside into getComputer");        return message;    }    public void messageing(){        message.messageing();    }}//Message类package com.home.model;public class Message {    public Message(){        System.out.println("inside into Message constructor!");    }    public void messageing(){        System.out.println("inside messageing....");    }}//配置文件<!-- 注入内部 Beans -->    <bean id="computer" class="com.home.model.Computer">        <property name="message">            <bean id="message" class="com.home.model.Message">            </bean>        </property>   </bean>

四、Spring 注入集合

  ****<list>它有助于连线，如注入一列值，允许重复。  <set>它有助于连线一组值，但不能重复。   <map>它可以用来注入名称-值对的集合，其中名称和值可以是任何类型。      <props>它可以用来注入名称-值对的集合，其中名称和值都是字符串类型。****

package com.home.model;import java.util.List;import java.util.Map;import java.util.Properties;import java.util.Set;public class CollectionExample {    List addressList;//它有助于连线，如注入一列值，允许重复    Set  addressSet;//它有助于连线一组值，但不能重复    Map  addressMap;//它可以用来注入名称-值对的集合，其中名称和值可以是任何类型    Properties addressProp;//它可以用来注入名称-值对的集合，其中名称和值都是字符串类型    public List getAddressList() {        System.out.println("List:"+addressList);        return addressList;    }    public void setAddressList(List addressList) {        this.addressList = addressList;    }    public Set getAddressSet() {        System.out.println("Set:"+addressSet);        return addressSet;    }    public void setAddressSet(Set addressSet) {        this.addressSet = addressSet;    }    public Map getAddressMap() {        System.out.println("Map:"+addressMap);        return addressMap;    }    public void setAddressMap(Map addressMap) {        this.addressMap = addressMap;    }    public Properties getAddressProp() {        return addressProp;    }    public void setAddressProp(Properties addressProp) {        System.out.println("Prop:"+addressProp);        this.addressProp = addressProp;    }}//配置文件如下： <!-- 注入集合 -->    <bean id="collectionExample" class="com.home.model.CollectionExample">        <property name="addressList">            <list>               <value>China</value>               <value>India</value>               <value>India</value>               <value>USA</value>            </list>        </property>        <property name="addressSet">            <set>               <value>China</value>               <value>India</value>               <value>India</value>               <value>USA</value>            </set>        </property>        <property name="addressMap">            <map>                <entry key="1" value="China"></entry>                <entry key="2" value="India"></entry>                <entry key="3" value="India"></entry>                <entry key="4" value="USA"></entry>            </map>        </property>        <property name="addressProp">             <props>                 <prop key="one">China</prop>                  <prop key="two">India</prop>                  <prop key="three">India</prop>                  <prop key="four">USA</prop>              </props>        </property>    </bean>//测试类  @RequestMapping(value="/collection",method=RequestMethod.GET)    public ModelAndView collection(){        ModelAndView view=new ModelAndView("/login/hello");        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");        CollectionExample collectionExample=(CollectionExample)context.getBean("collectionExample");        collectionExample.getAddressList();        collectionExample.getAddressSet();        collectionExample.getAddressMap();        collectionExample.getAddressProp();        return view;    }打印结果如下：List:[China, India, India, USA]Set:[China, India, USA]Map:{1=China, 2=India, 3=India, 4=USA}Prop:{two=India, one=China, three=India, four=USA}