spring mvc的注入属性原理，怎样才能知道哪个属性注入到哪里

定义一些抽象的方法：

[java]

package com.huxin.springinject.dao; 

 

public interface Person { 

    public void save(); 

    public void useAxe(); 

} 

package com.huxin.springinject.dao;

public interface Person {

    public void save();

    public void useAxe();

}

[java]

package com.huxin.springinject.dao; 

 

public interface Axe { 

   public void  chop(); 

    

} 

package com.huxin.springinject.dao;

public interface Axe {

   public void  chop();

  

}

实现的一些方法：

[java]

package com.huxin.springinject.dao.impl; 

 

import com.huxin.springinject.dao.Axe; 

import com.huxin.springinject.dao.Person; 

 

public class Chinese implements Person { 

    private Axe axe;     

    public Axe getAxe() { 

        return axe; 

    } 

 

    public void setAxe(Axe axe) { 

        this.axe = axe; 

    } 

 

    public void save() { 

        System.out.println("保存人的方法"); 

    }    

    public void useAxe(){ 

        axe.chop(); 

    } 

} 

package com.huxin.springinject.dao.impl;

import com.huxin.springinject.dao.Axe;

import com.huxin.springinject.dao.Person;

public class Chinese implements Person {

 private Axe axe; 

 public Axe getAxe() {

  return axe;

 }

 public void setAxe(Axe axe) {

  this.axe = axe;

 }

 public void save() {

        System.out.println("保存人的方法");

 } 

 public void useAxe(){

  axe.chop();

 }

}

 

[java]

package com.huxin.springinject.dao.impl; 

 

import com.huxin.springinject.dao.Axe; 

 

public class StoneAxe implements Axe { 

 

    @Override 

    public void chop() { 

       System.out.println("铁斧头砍柴真慢"); 

 

    } 

 

} 

package com.huxin.springinject.dao.impl;

import com.huxin.springinject.dao.Axe;

public class StoneAxe implements Axe {

 @Override

 public void chop() {

    System.out.println("铁斧头砍柴真慢");

 }

}

这里是关键spring框架模拟的实现的一些原理！！！

[java]

package junit.test; 

import java.beans.Introspector; 

import java.beans.PropertyDescriptor; 

import java.lang.reflect.Method; 

import java.net.URL; 

import java.util.ArrayList; 

import java.util.HashMap; 

import java.util.List; 

import java.util.Map; 

 

import org.apache.commons.beanutils.ConvertUtils; 

import org.dom4j.Document; 

import org.dom4j.Element; 

import org.dom4j.XPath; 

import org.dom4j.io.SAXReader; 

public class ApplicationContext { 

     List<BeanInformation> beansInformation = new ArrayList<BeanInformation>(); 

     Map<String,Object> singleton = new HashMap<String,Object>(); 

      

      

     public ApplicationContext(){}; 

     public ApplicationContext(String filename){ 

         readXml(filename); 

         initBean(); 

         this.injectObject(); 

     } 

     public void readXml(String filename){ 

         SAXReader saxReader = new SAXReader(); 

         Document document = null; 

         try{ 

             //使用反射机制,通过文件名加载文件路径  

             URL xmlPath = this.getClass().getClassLoader().getResource(filename); 

              

             //通过文件路径获得这个文件的document对象  

             document = saxReader.read(xmlPath); 

              

             Map<String,String> nsMap = new HashMap<String,String>(); 

             nsMap.put("ns","http://www.springframework.org/schema/beans");//加入命名空间 

              

             XPath xsub = document.createXPath("//ns:beans/ns:bean");//创建beans/bean查询路径 

             xsub.setNamespaceURIs(nsMap);//设置命名空间  

         

             //获得所有路径下的节点  

             List<Element> beans = xsub.selectNodes(document);//获取文档下所有bean节点  

             for(Element element : beans){ 

                 System.out.println(element.attributeValue("id")); 

                 System.out.println(element.attributeValue("class")); 

                  

                 BeanInformation beanInformation = new BeanInformation(); 

                 beanInformation.setId(element.attributeValue("id")); 

                 beanInformation.setName(element.attributeValue("class")); 

                  

                 XPath xref = element.createXPath("ns:property");//创建properties查询路径  

                 xref.setNamespaceURIs(nsMap);//设置命名空间  

                  

                 List<Element> propertys = xref.selectNodes(element); 

                 for(Element property : propertys){ 

                     PropertyInformation propertyInformation = new PropertyInformation(); 

                     propertyInformation.setName(property.attributeValue("name")); 

                     propertyInformation.setRef(property.attributeValue("ref")); 

                     propertyInformation.setValue(property.attributeValue("value")); 

                     beanInformation.getPropertyInformation().add(propertyInformation); 

                 } 

                 beansInformation.add(beanInformation); 

             } 

         } catch(Exception e){ 

             e.printStackTrace(); 

         } 

     } 

      

     public void initBean(){ 

         for(BeanInformation beanInformation: beansInformation){ 

             if(beanInformation.getName()!=null && !"".equals(beanInformation.getName())){ 

                 //通过反射机制，根据名字初始化这个类  

                try { 

                    singleton.put(beanInformation.getId(), Class.forName(beanInformation.getName()).newInstance()); 

                } catch (Exception e) { 

                    e.printStackTrace(); 

                } 

             } 

         } 

     } 

      

     /**

     *    关于注入的实现

     */ 

    private void injectObject() { 

        for(BeanInformation beanInformation : beansInformation){ 

            Object bean = singleton.get(beanInformation.getId()); 

            if(bean!=null){ 

                try { 

                    PropertyDescriptor[] ps = Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors(); 

                    for(PropertyInformation propertyInformation : beanInformation.getPropertyInformation()){ 

                        for(PropertyDescriptor properdesc : ps){ 

                            if(propertyInformation.getName().equals(properdesc.getName())){ 

                                Method setter = properdesc.getWriteMethod();//获取属性的setter方法 ,private  

                                if(setter!=null){ 

                                    Object value = null; 

                                    if(propertyInformation.getRef()!=null && !"".equals(propertyInformation.getRef().trim())){ 

                                        value = singleton.get(propertyInformation.getRef()); 

                                    }else{ 

                                        value = ConvertUtils.convert(propertyInformation.getValue(), properdesc.getPropertyType()); 

                                    } 

                                    setter.setAccessible(true); 

                                    setter.invoke(bean, value);//把引用对象注入到属性  

                                } 

                                break; 

                            } 

                        } 

                    } 

                } catch (Exception e) { 

                } 

            } 

        } 

    } 

     

     public Object getBean(String id){ 

         return this.singleton.get(id);       

     } 

} 

package junit.test;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

import java.lang.reflect.Method;

import java.net.URL;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.apache.commons.beanutils.ConvertUtils;

import org.dom4j.Document;

import org.dom4j.Element;

import org.dom4j.XPath;

import org.dom4j.io.SAXReader;

public class ApplicationContext {

     List<BeanInformation> beansInformation = new ArrayList<BeanInformation>();

     Map<String,Object> singleton = new HashMap<String,Object>();

    

    

     public ApplicationContext(){};

     public ApplicationContext(String filename){

      readXml(filename);

      initBean();

      this.injectObject();

     }

     public void readXml(String filename){

      SAXReader saxReader = new SAXReader();

      Document document = null;

      try{

          //使用反射机制,通过文件名加载文件路径

       URL xmlPath = this.getClass().getClassLoader().getResource(filename);

      

       //通过文件路径获得这个文件的document对象

       document = saxReader.read(xmlPath);

      

       Map<String,String> nsMap = new HashMap<String,String>();

           nsMap.put("ns","http://www.springframework.org/schema/beans");//加入命名空间

          

           XPath xsub = document.createXPath("//ns:beans/ns:bean");//创建beans/bean查询路径

           xsub.setNamespaceURIs(nsMap);//设置命名空间

     

       //获得所有路径下的节点

       List<Element> beans = xsub.selectNodes(document);//获取文档下所有bean节点

       for(Element element : beans){

        System.out.println(element.attributeValue("id"));

        System.out.println(element.attributeValue("class"));

       

        BeanInformation beanInformation = new BeanInformation();

        beanInformation.setId(element.attributeValue("id"));

        beanInformation.setName(element.attributeValue("class"));

       

        XPath xref = element.createXPath("ns:property");//创建properties查询路径

        xref.setNamespaceURIs(nsMap);//设置命名空间

       

        List<Element> propertys = xref.selectNodes(element);

        for(Element property : propertys){

         PropertyInformation propertyInformation = new PropertyInformation();

         propertyInformation.setName(property.attributeValue("name"));

         propertyInformation.setRef(property.attributeValue("ref"));

         propertyInformation.setValue(property.attributeValue("value"));

         beanInformation.getPropertyInformation().add(propertyInformation);

        }

        beansInformation.add(beanInformation);

       }

         } catch(Exception e){

          e.printStackTrace();

         }

     }

    

     public void initBean(){

      for(BeanInformation beanInformation: beansInformation){

       if(beanInformation.getName()!=null && !"".equals(beanInformation.getName())){

        //通过反射机制，根据名字初始化这个类

       try {

     singleton.put(beanInformation.getId(), Class.forName(beanInformation.getName()).newInstance());

    } catch (Exception e) {

     e.printStackTrace();

    }

       }

      }

     }

    

     /**

   *    关于注入的实现

bd1e

   */

  private void injectObject() {

   for(BeanInformation beanInformation : beansInformation){

    Object bean = singleton.get(beanInformation.getId());

    if(bean!=null){

     try {

      PropertyDescriptor[] ps = Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();

      for(PropertyInformation propertyInformation : beanInformation.getPropertyInformation()){

       for(PropertyDescriptor properdesc : ps){

        if(propertyInformation.getName().equals(properdesc.getName())){

         Method setter = properdesc.getWriteMethod();//获取属性的setter方法 ,private

         if(setter!=null){

          Object value = null;

          if(propertyInformation.getRef()!=null && !"".equals(propertyInformation.getRef().trim())){

           value = singleton.get(propertyInformation.getRef());

          }else{

           value = ConvertUtils.convert(propertyInformation.getValue(), properdesc.getPropertyType());

          }

          setter.setAccessible(true);

          setter.invoke(bean, value);//把引用对象注入到属性

         }

         break;

        }

       }

      }

     } catch (Exception e) {

     }

    }

   }

  }

  

     public Object getBean(String id){

   return this.singleton.get(id);  

     }

}

[java]

package junit.test; 

 

import java.util.HashSet; 

import java.util.Set; 

 

public class BeanInformation { 

    private String id; 

    private String name; 

    private Set<PropertyInformation> propertyInformation = new HashSet<PropertyInformation>(); 

    public String getId() { 

        return id; 

    } 

    public void setId(String id) { 

        this.id = id; 

    } 

    public String getName() { 

        return name; 

    } 

    public void setName(String name) { 

        this.name = name; 

    } 

    public Set<PropertyInformation> getPropertyInformation() { 

        return propertyInformation; 

    } 

    public void setPropertyInformation(Set<PropertyInformation> propertyInformation) { 

        this.propertyInformation = propertyInformation; 

    } 

} 

package junit.test;

import java.util.HashSet;

import java.util.Set;

public class BeanInformation {

    private String id;

    private String name;

    private Set<PropertyInformation> propertyInformation = new HashSet<PropertyInformation>();

 public String getId() {

  return id;

 }

 public void setId(String id) {

  this.id = id;

 }

 public String getName() {

  return name;

 }

 public void setName(String name) {

  this.name = name;

 }

 public Set<PropertyInformation> getPropertyInformation() {

  return propertyInformation;

 }

 public void setPropertyInformation(Set<PropertyInformation> propertyInformation) {

  this.propertyInformation = propertyInformation;

 }

}

[java]

package junit.test; 

 

public class PropertyInformation { 

    private String name; 

    private String ref; 

    private String value; 

    public String getName() { 

        return name; 

    } 

    public void setName(String name) { 

        this.name = name; 

    } 

    public String getRef() { 

        return ref; 

    } 

    public void setRef(String ref) { 

        this.ref = ref; 

    } 

    public String getValue() { 

        return value; 

    } 

    public void setValue(String value) { 

        this.value = value; 

    } 

} 

package junit.test;

public class PropertyInformation {

    private String name;

    private String ref;

    private String value;

 public String getName() {

  return name;

 }

 public void setName(String name) {

  this.name = name;

 }

 public String getRef() {

  return ref;

 }

 public void setRef(String ref) {

  this.ref = ref;

 }

 public String getValue() {

  return value;

 }

 public void setValue(String value) {

  this.value = value;

 }

}

测试类：

[java]

package junit.test; 

 

import com.huxin.springinject.dao.Person; 

 

public class Test { 

    public static void main(String[] args) { 

        ApplicationContext ac = new ApplicationContext("applicationContext.xml"); 

        Person person = (Person)ac.getBean("chinese"); 

        person.save(); 

        person.useAxe(); 

    } 

} 

package junit.test;

import com.huxin.springinject.dao.Person;

public class Test {

 public static void main(String[] args) {

  ApplicationContext ac = new ApplicationContext("applicationContext.xml");

  Person person = (Person)ac.getBean("chinese");

  person.save();

  person.useAxe();

 }

}

[html]

<?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:context="http://www.springframework.org/schema/context"   

       xsi:schemaLocation="http://www.springframework.org/schema/beans 

           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
           http://www.springframework.org/schema/context  
           http://www.springframework.org/schema/context/spring-context-3.0.xsd"> 
        

       

      <bean id="chinese"  class="com.huxin.springinject.dao.impl.Chinese"> 

         <property name="axe" ref="stoneAxe"/> 

      </bean> 

      <bean id="stoneAxe" class="com.huxin.springinject.dao.impl.StoneAxe"/> 

</beans> 

<?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:context="http://www.springframework.org/schema/context" 

       xsi:schemaLocation="http://www.springframework.org/schema/beans

           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd">
      

     

      <bean id="chinese"  class="com.huxin.springinject.dao.impl.Chinese">

         <property name="axe" ref="stoneAxe"/>

      </bean>

      <bean id="stoneAxe" class="com.huxin.springinject.dao.impl.StoneAxe"/>

</beans>

补充说明： 需要导入dom4j相应的辅助包和junit辅助包！