模拟spring框架注入实现原理 - JAVA

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 beansInformation = new ArrayList();
Map singleton = new HashMap();

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 nsMap = new HashMap();
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 beans = xsub.selectNodes(document);//获取文档下所有bean节点
for(Element element : beans){
System.out.println(element.attributeva lue("id"));
System.out.println(element.attributeva lue("class"));

BeanInformation beanInformation = new BeanInformation();
beanInformation.setId(element.attributeva lue("id"));
beanInformation.setName(element.attributeva lue("class"));

XPath xref = element.createXPath("ns:property");//创建properties查询路径
xref.setNamespaceURIs(nsMap);//设置命名空间

List propertys = xref.selectNodes(element);
for(Element property : propertys){
PropertyInformation propertyInformation = new PropertyInformation();
propertyInformation.setName(property.attributeva lue("name"));
propertyInformation.setRef(property.attributeva lue("ref"));
propertyInformation.setValue(property.attributeva lue("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

模拟spring框架注入实现原理 (四)