一个简单的模仿spring的ioc实现

package cm.ioc.io; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import cm.ioc.exception.IdNotFoundException; import cm.ioc.exception.PropertyNullException; import javax.xml.parsers.DocumentBuilderFactory; public class XmlReader { private Document doc; public XmlReader(String xmlPath){ try { doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(xmlPath); }catch(Exception e){ e.printStackTrace(); } } //通过bean的id属性获取对应的Class属性 public String getClassById(String id){ NodeList nodeList = doc.getElementsByTagName("bean"); Element element = null; for(int i=0;i<nodeList.getLength();i++){ if(((Element)nodeList.item(i)).getAttribute("id").equals(id)){ element = (Element)nodeList.item(i); } } if(element==null){ throw new IdNotFoundException("找不到id:"+id); } return element.getAttribute("class"); } //获取所有的id一个id对一个对象 public List<String> getAllId(){ NodeList nodeList = doc.getElementsByTagName("bean"); List<String> allId = new ArrayList<String>(); for(int i=0;i<nodeList.getLength();i++){ String id = ((Element)nodeList.item(i)).getAttribute("id"); allId.add(id); } return allId; } //通过id获取配置的成员属性 public Map<String,String> getPropertysById(String id){ NodeList nodeList = doc.getElementsByTagName("bean"); Map<String,String> propertys = new HashMap<String,String>(); Element element = null; for(int i=0;i<nodeList.getLength();i++){ if(((Element)nodeList.item(i)).getAttribute("id").equals(id)){ element = (Element) nodeList.item(i); } } if(element==null){ throw new IdNotFoundException("找不到id:"+id); } nodeList = element.getElementsByTagName("property"); for(int i=0;i<nodeList.getLength();i++){ element = (Element) nodeList.item(i); String name = element.getAttribute("name"); String ref = element.getAttribute("ref"); if(name==""||ref==""){ throw new PropertyNullException("请将id:"+id+"属性补充完整"); } propertys.put(name, ref); } if(propertys.size()==0){ propertys = null; } return propertys; } public static void main(String[] args) { XmlReader reader = new XmlReader("src/cm/ioc/doc/applicationContext.xml"); System.out.println(reader.getClassById("mywheel")); System.out.println(reader.getAllId()); System.out.println(reader.getPropertysById("mywheel")); System.out.println(reader.getPropertysById("car")); } }