IoC的简易实现

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java 代码

package com.viwo.bean.factory;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.digester.Digester;
import org.apache.log4j.Logger;

import com.viwo.bean.config.ConfigBean;
import com.viwo.bean.interceptor.InterceptorProxyFactory;
import com.viwo.sqlmap.config.SqlMapConfig;

/**
 * A simple IoC Container for beans, manage beans for you.
 *
 * @author viwo
 *
 */
public class BeanFactory {

 private final static Logger logger = Logger.getLogger(SqlMapConfig.class);
 private Map configBeanMap = new HashMap();
 private static Map beanFactoryMap = new HashMap();

    /**
     * a static synchronized method to get the Bean from a gived beanId
     *
     * @param beanId
     * @return Object
     */
 public static synchronized Object getBean(String beanId)
 {
  logger.info("[viwo]-->[enter getBean]");
  BeanFactory beanFactory = getBeanFactory();
  Map cfgMap = beanFactory.getConfigBeanMap();
  ConfigBean cfgBean = (ConfigBean)cfgMap.get(beanId);
  if(cfgBean == null)
  {
   //if there have not beanId will return null
   return null;
  }
  String transaction = cfgBean.getTransaction();
  Object beanObject = null;
  try
  {
   beanObject = Class.forName(cfgBean.getType()).newInstance();
  }
  catch (Exception e)
  {
   e.printStackTrace();
  }

  Iterator itProperty = cfgBean.getPropertyMap().keySet().iterator();
  Iterator itRef = cfgBean.getRefMap().keySet().iterator();

  while(itProperty.hasNext())
  {
   String propertyName = itProperty.next().toString();
   String propertyValue = cfgBean.getPropertyMap().get(propertyName).toString();
   try
   {
    BeanUtils.setProperty(beanObject, propertyName, propertyValue);
   }
   catch (Exception e)
   {
    e.printStackTrace();
   }
  }

  while(itRef.hasNext())
  {
   String refName = itRef.next().toString();
   String refValue = cfgBean.getRefMap().get(refName).toString();
   Object refObject = BeanFactory.getBean(refValue);
   try
   {
    BeanUtils.setProperty(beanObject, refName, refObject);
   }
   catch (Exception e)
   {
    e.printStackTrace();
   }
  }
  //System.out.println(cfgBean.getType());
  if(transaction!=null&&!transaction.equals(""))
  {
   String[] trans = transaction.split(",");
   beanObject = InterceptorProxyFactory.getInterceptorProxyedObject(beanObject,trans);
  }
  return beanObject;
 }

    /**
     * a static synchronized method to get the BeanFactoryConfig
     *
     * this method will initialize the properity of BeanFactory
     *
     * @return BeanFactory
     */
 private static synchronized BeanFactory getBeanFactory()
 {
  BeanFactory beanFactory = null;
  String path = "bean-config.xml";
  if(beanFactoryMap.get(path)==null)
  {
   Digester digester = new Digester();
      digester.setValidating(false);
      digester.addObjectCreate("beans", "com.viwo.bean.factory.BeanFactory");

      digester.addObjectCreate("beans/bean", "com.viwo.bean.config.ConfigBean");

      digester.addSetProperties("beans/bean");

      digester.addCallMethod("beans/bean/property", "setProperty", 2);
      digester.addCallParam("beans/bean/property", 0, "name");
      digester.addCallParam("beans/bean/property", 1, "value");

      digester.addCallMethod("beans/bean/ref", "setRef", 2);
         digester.addCallParam("beans/bean/ref", 0, "name");
      digester.addCallParam("beans/bean/ref", 1, "value");

      digester.addSetNext("beans/bean", "addConfigBean", "com.viwo.bean.config.ConfigBean");

      try
      {
       beanFactory = (BeanFactory)digester.parse(Thread.currentThread().getContextClassLoader().getResource("/"+path).getFile());
       beanFactoryMap.put(path, beanFactory);
      }
   catch (Exception e)
   {
    System.out.println(e.getMessage());
   }
  }
  else
  {
   beanFactory = (BeanFactory)beanFactoryMap.get(path);
  }
  return beanFactory;
 }
 public void addConfigBean(ConfigBean configBean)
 {
  configBeanMap.put(configBean.getId(), configBean);
 }
 public Map getConfigBeanMap()
 {
  return configBeanMap;
 }

}