spring学习笔记（二） 模拟spring注入
spring学得模模糊糊，许多东西也只是过了一下，其实还是不懂，记下来供以后用的时候能够得到一些帮助吧。
beans.xml
<?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="personServiceBean" ref="personDaoBean" /></bean><bean id="personDaoBean" /></beans>
单元测试SpringTest
package junit.test;import org.junit.Test;import com.gentle.service.PersonService;import com.gentle.context.support.GentleClassPathXmlApplicationContext;import junit.framework.TestCase;public class SpringTest extends TestCase {@Testpublic void test() {GentleClassPathXmlApplicationContext context = new GentleClassPathXmlApplicationContext("beans.xml");PersonService personService = (PersonService) context.getBean("personServiceBean");personService.Save();}}ClassPathXmlApplicationContext的模拟类GentleClassPathXmlApplicationContext
package com.gentle.context.support;import java.beans.IntrospectionException;import java.beans.Introspector;import java.beans.PropertyDescriptor;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 com.gentle.context.support.BeanDefinition;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.Element;import org.dom4j.XPath;import org.dom4j.io.SAXReader;public class GentleClassPathXmlApplicationContext {private List<BeanDefinition> beanDefinitions = new ArrayList<BeanDefinition>();private Map<String, Object> singletons = new HashMap<String, Object>();public GentleClassPathXmlApplicationContext(String fileName) {this.readXML(fileName);this.instanceBeans();this.injectObject();}/** * 为bean的属性注入值 */private void injectObject() {for(BeanDefinition beanDefinition:beanDefinitions) {//循环所有的beanObject bean = singletons.get(beanDefinition.getId());//得到beanif(bean!=null) {try {PropertyDescriptor[] ps = Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();for(PropertyDefinition propertyDefinition:beanDefinition.getProperties()) {for(PropertyDescriptor propertyDescriptor : ps) {if(propertyDefinition.getName().equals(propertyDescriptor.getName())) {Method setter = propertyDescriptor.getWriteMethod();//取得属性的setter方法if(setter!=null) {Object value = singletons.get(propertyDefinition.getRef());setter.setAccessible(true);//设置私有方法访问权限setter.invoke(bean, value);//把引用对象注入到属性中}break;}}}} catch (IntrospectionException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}}}/** * 实例化容器 */private void instanceBeans() {for(BeanDefinition definition:beanDefinitions) {try {if(definition.getClassName()!=null && !"".equals(definition.getClassName())) {singletons.put(definition.getId(), Class.forName(definition.getClassName()).newInstance());}} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();}}}/** * 读取XML配置文件 * * @param fileName */@SuppressWarnings("unchecked")private void readXML(String fileName) {SAXReader reader = new SAXReader();Document document = null;try {URL xmlPath = this.getClass().getClassLoader().getResource(fileName);// 取得文件document = reader.read(xmlPath);// 读取文件内容Map<String, String> nsMap = new HashMap<String, String>();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List<Element> beans = xsub.selectNodes(document);// 获取文档下所有bean节点for (Element element : beans) {String id = element.attributeValue("id");// 获取id属性值String className = element.attributeValue("class");// 获取class属性值BeanDefinition definition = new BeanDefinition(id, className);XPath propertysub = element.createXPath("ns:property");//创建查询路径propertysub.setNamespaceURIs(nsMap);//设置命名空间List<Element> properties = propertysub.selectNodes(element);//获取property下面所有节点for(Element property:properties) {String propertyName = property.attributeValue("name");//获取name属性值String propertyRef = property.attributeValue("ref");//获取ref属性值PropertyDefinition propertyDefinition = new PropertyDefinition(propertyName, propertyRef);//实例化对象definition.getProperties().add(propertyDefinition);//添加propertyDefinition对象到bean对象}beanDefinitions.add(definition);}} catch (DocumentException e) {e.printStackTrace();}}public Object getBean(String beanName) {return singletons.get(beanName);}}BeanDefinition
package com.gentle.context.support;import java.util.ArrayList;import java.util.List;public class BeanDefinition {private String id;private String className;private List<PropertyDefinition> properties = new ArrayList<PropertyDefinition>();public List<PropertyDefinition> getProperties() {return properties;}public void setProperties(List<PropertyDefinition> properties) {this.properties = properties;}public BeanDefinition(String id,String className) {this.id = id;this.setClassName(className);}public String getId() {return id;}public void setId(String id) {this.id = id;}public void setClassName(String className) {this.className = className;}public String getClassName() {return className;}}PropertyDefinition
package com.gentle.context.support;public class PropertyDefinition {private String name;private String ref;public PropertyDefinition(String name, String ref) {this.name = name;this.ref = ref;}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;}}PersonDao
package com.gentle.dao;public interface PersonDao {public abstract void save();}PersonDaoBean
package com.gentle.dao.impl;import com.gentle.dao.PersonDao;public class PersonDaoBean implements PersonDao {public void save() {System.out.println("调用PersonDaoBean中的save()方法");}}PersonService
package com.gentle.service;public interface PersonService {public abstract void Save();}PersonServiceBean
package com.gentle.service.impl;import com.gentle.dao.PersonDao;import com.gentle.service.PersonService;public class PersonServiceBean implements PersonService {private PersonDao personDao;public PersonDao getPersonDao() {return personDao;}public void setPersonDao(PersonDao personDao) {this.personDao = personDao;}@Overridepublic void Save() {personDao.save();}}