Java反射机制详解(3) -java的反射和代理实现IOC模式 模拟spring

 package org.amigo.reflection;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
* bean工厂类.   
*/
public class BeanFactory {
       private Map<String, Object> beanMap = new HashMap<String, Object>();
       /**
       * bean工厂的初始化.
       * @param xml xml配置文件
       */
       public void init(String xml) {
              try {
                     //读取指定的配置文件
                     SAXReader reader = new SAXReader();
                     ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
                     //从class目录下获取指定的xml文件
                     InputStream ins = classLoader.getResourceAsStream(xml);
                     Document doc = reader.read(ins);
                     Element root = doc.getRootElement();  
                     Element foo;
                    
                     //遍历bean
                     for (Iterator i = root.elementIterator("bean"); i.hasNext();) {  
                            foo = (Element) i.next();
                            //获取bean的属性id和class
                            Attribute id = foo.attribute("id");  
                            Attribute cls = foo.attribute("class");
                           
                            //利用Java反射机制，通过class的名称获取Class对象
                            Class bean = Class.forName(cls.getText());
                           
                            //获取对应class的信息
                            java.beans.BeanInfo info = java.beans.Introspector.getBeanInfo(bean);
                            //获取其属性描述
                            java.beans.PropertyDescriptor pd[] = info.getPropertyDescriptors();
                            //设置值的方法
                            Method mSet = null;
                            //创建一个对象
                            Object obj = bean.newInstance();
                           
                            //遍历该bean的property属性
                            for (Iterator ite = foo.elementIterator("property"); ite.hasNext();) {  
                                   Element foo2 = (Element) ite.next();
                                   //获取该property的name属性
                                   Attribute name = foo2.attribute("name");
                                   String value = null;
                                  
                                   //获取该property的子元素value的值
                                   for(Iterator ite1 = foo2.elementIterator("value"); ite1.hasNext();) {
                                          Element node = (Element) ite1.next();
                                          value = node.getText();
                                          break;
                                   }
                                  
                                   for (int k = 0; k < pd.length; k++) {
                                          if (pd[k].getName().equalsIgnoreCase(name.getText())) {
                                                 mSet = pd[k].getWriteMethod();
                                                 //利用Java的反射极致调用对象的某个set方法，并将值设置进去
                                                 mSet.invoke(obj, value);
                                          }
                                   }
                            }
                           
                            //将对象放入beanMap中，其中key为id值，value为对象
                            beanMap.put(id.getText(), obj);
                     }
              } catch (Exception e) {
                     System.out.println(e.toString());
              }
       }
      
       /**
       * 通过bean的id获取bean的对象.
       * @param beanName bean的id
       * @return 返回对应对象
       */
       public Object getBean(String beanName) {
              Object obj = beanMap.get(beanName);
              return obj;
       }
      
       /**
       * 测试方法.
       * @param args
       */
       public static void main(String[] args) {
              BeanFactory factory = new BeanFactory();
              factory.init("config.xml");
              JavaBean javaBean = (JavaBean) factory.getBean("javaBean");
              System.out.println("userName=" + javaBean.getUserName());
              System.out.println("password=" + javaBean.getPassword());
       }
}

 package org.amigo.reflection;
/**
*
* 简单的bean，用于测试  
*/
public class JavaBean {
       private String userName;
       private String password;
      
    public String getPassword() {
              return password;
       }
       public String getUserName() {
              return userName;
       }
       public void setUserName(String userName) {
              this.userName = userName;
       }
       public void setPassword(String password) {
              this.password = password;
       }
}

 <?xml version="1.0" encoding="UTF-8"?>
<beans>
    <bean id="javaBean" class="org.amigo.reflection.JavaBean">
       <property name="userName">
           <value>阿蜜果</value>
       </property>
       <property name="password">
           <value>12345678</value>
       </property>
    </bean>
</beans>