java模拟spring ioc

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Xml代码

<?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>

Java代码

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;      }  }

Java代码

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;      }  }

Java代码

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
Java代码

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 block              e.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 block              e.printStackTrace();          } catch (InstantiationException e) {              // TODO Auto-generated catch block              e.printStackTrace();          } catch (IllegalAccessException e) {              // TODO Auto-generated catch block              e.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private                              setterMethod.invoke(bean, temp);//把引用对象注入到属性                              }                              break;                          }                      }                      }                  }              }          } catch (Exception e) {              // TODO Auto-generated catch block              e.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 block              e.printStackTrace();          }       }      /**      * 获取bean实例      * @param beanName      * @return      */      public Object getBean(String beanName){          return this.sigletons.get(beanName);      }  }

Java代码

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

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