java模拟spring ioc

 

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xsi:schemaLocation="http://www.springframework.org/schema/beans           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">           <bean id="personDao" class="junit.test12.PersonDaoBean"/>          <bean id="personService" class="junit.test12.PersonServiceBean">           <property name="id" value="24"/>          <property name="name" value="zyj"/>          <!--  <property name="personDao" ref="personDao"/> -->          </bean></beans>

 

package junit.test12;import java.util.ArrayList;import java.util.List;/** * xml中的<bean/>的定义 * @author Administrator * */public class BeanDefinition {private String id;private String clazz;private List<PropertyDefinition> propertyDefinitions=new ArrayList<PropertyDefinition>();public BeanDefinition(String id, String clazz) {super();this.id = id;this.clazz = clazz;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getClazz() {return clazz;}public void setClazz(String clazz) {this.clazz = clazz;}public List<PropertyDefinition> getPropertyDefinitions() {return propertyDefinitions;}public void setPropertyDefinitions(List<PropertyDefinition> propertyDefinitions) {this.propertyDefinitions = propertyDefinitions;}} 

 

 

package junit.test12;public class PropertyDefinition {private String name;private String ref;private String value;public PropertyDefinition(String name, String ref,String value) {super();this.name = name;this.ref = ref;this.value=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.test12;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.FIELD,ElementType.METHOD})public @interface UserDefinedResource {public String name() default "";}

 

//使用dom4j读取spring配置文件

package junit.test12;import java.beans.IntrospectionException;import java.beans.Introspector;import java.beans.PropertyDescriptor;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;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 junit.test12.BeanDefinition;import org.apache.commons.beanutils.ConvertUtils;import org.apache.commons.beanutils.Converter;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.Element;import org.dom4j.XPath;import org.dom4j.io.SAXReader;/** * 自定义容器 * @author Administrator * */public class UserDefinedClassPathXMLApplicationContext {private List<BeanDefinition> beanDefinitions=new ArrayList<BeanDefinition>();private Map<String, Object> sigletons=new HashMap<String, Object>();public UserDefinedClassPathXMLApplicationContext(String filename){this.readXML(filename);this.instanceBeans();this.annotationInject();this.injectObject();}/** * 读取xml配置文件 * @param filename */private void readXML(String filename){SAXReader saxReader=new SAXReader();Document document=null;try {URL xmlPath=this.getClass().getClassLoader().getResource(filename);document=saxReader.read(xmlPath);XPath xPath=document.createXPath("//ns:beans/ns:bean");//创建beans/bean查询路径。从根路径开始Map<String, String> nsMap=new HashMap<String, String>();nsMap.put("ns", "http://www.springframework.org/schema/beans");//加入命名空间xPath.setNamespaceURIs(nsMap);//设置命名空间List<Element> beans=xPath.selectNodes(document);//获取文档下所有bean节点 for (Element element : beans) {String id=element.attributeValue("id");String clazz=element.attributeValue("class");BeanDefinition beanDefinition=new BeanDefinition(id, clazz);XPath xPath2=element.createXPath("ns:property");//从相对路径开始xPath2.setNamespaceURIs(nsMap);List<Element> propertys=xPath2.selectNodes(element);for (Element element2 : propertys) {String name=element2.attributeValue("name");String ref=element2.attributeValue("ref");String value=element2.attributeValue("value");PropertyDefinition propertyDefinition=new PropertyDefinition(name, ref,value);beanDefinition.getPropertyDefinitions().add(propertyDefinition);}beanDefinitions.add(beanDefinition);}} catch (DocumentException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** * 完成bean的实例化 */private void instanceBeans(){try {for (BeanDefinition beanDefinition : beanDefinitions) {if (beanDefinition.getClazz()!=null&&!"".equals(beanDefinition.getClazz().trim())) {sigletons.put(beanDefinition.getId(), Class.forName(beanDefinition.getClazz()).newInstance());}}} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (InstantiationException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** * 为bean对象的属性注入值 * @throws IntrospectionException  * @throws InvocationTargetException  * @throws IllegalAccessException  * @throws IllegalArgumentException  */private void injectObject()  {try {for (BeanDefinition beanDefinition : beanDefinitions) {Object bean=sigletons.get(beanDefinition.getId());if (bean!=null) {PropertyDescriptor[] ps=Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();for(PropertyDefinition propertyDefinition:beanDefinition.getPropertyDefinitions()){for (PropertyDescriptor propertyDescriptor : ps) {if (propertyDefinition.getName().equals(propertyDescriptor.getName())) {Method setterMethod=propertyDescriptor.getWriteMethod();//获取属性的setter方法if (setterMethod!=null) {Object temp=null;if (propertyDefinition.getRef()!=null&&!"".equals(propertyDefinition.getRef().trim())) {temp=sigletons.get(propertyDefinition.getRef());}else if (propertyDefinition.getValue()!=null&&!"".equals(propertyDefinition.getValue().trim())) {temp=ConvertUtils.convert(propertyDefinition.getValue(), propertyDescriptor.getPropertyType());}setterMethod.setAccessible(true);//防止setter方法为privatesetterMethod.invoke(bean, temp);//把引用对象注入到属性}break;}}}}}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** * 通过注解实现注入依赖对象 * @throws IntrospectionException  * @throws InvocationTargetException  * @throws IllegalAccessException  * @throws IllegalArgumentException  */private void annotationInject(){try {for (String beanName : sigletons.keySet()) {Object bean=sigletons.get(beanName);if (bean!=null) {PropertyDescriptor[] ps=Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();for (PropertyDescriptor propertyDescriptor : ps) {Method setterMethod=propertyDescriptor.getWriteMethod();if (setterMethod!=null&&setterMethod.isAnnotationPresent(UserDefinedResource.class)) {UserDefinedResource userDefinedResource=setterMethod.getAnnotation(UserDefinedResource.class);Object temp = null;if(userDefinedResource.name()!=null && !"".equals(userDefinedResource.name())){//一旦指定了name属性，就只能按名称装配了temp = sigletons.get(userDefinedResource.name());}else{temp = sigletons.get(propertyDescriptor.getName());if(temp==null){for(String key : sigletons.keySet()){if(propertyDescriptor.getPropertyType().isAssignableFrom(sigletons.get(key).getClass())){temp = sigletons.get(key);break;}}}}setterMethod.setAccessible(true);setterMethod.invoke(bean, temp);//把引用对象注入到属性}}Field[] fields = bean.getClass().getDeclaredFields();for(Field field : fields){if(field.isAnnotationPresent(UserDefinedResource.class)){UserDefinedResource userDefinedResource = field.getAnnotation(UserDefinedResource.class);Object temp = null;if(userDefinedResource.name()!=null && !"".equals(userDefinedResource.name())){temp = sigletons.get(userDefinedResource.name());}else{temp = sigletons.get(field.getName());if(temp==null){for(String key : sigletons.keySet()){if(field.getType().isAssignableFrom(sigletons.get(key).getClass())){temp = sigletons.get(key);break;}}}}field.setAccessible(true);//允许访问private字段field.set(bean, temp);}}}}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} }/** * 获取bean实例 * @param beanName * @return */public Object getBean(String beanName){return this.sigletons.get(beanName);}}

 

 

package junit.test12;import static org.junit.Assert.*;import junit.test12.PersonService;import junit.test12.UserDefinedClassPathXMLApplicationContext;import org.junit.Test;public class SpringTest {@Testpublic void instanceSpring() {UserDefinedClassPathXMLApplicationContext applicationContext=new UserDefinedClassPathXMLApplicationContext("beans.xml");PersonService personService=(PersonService) applicationContext.getBean("personService");personService.save();}}