自己模拟一个简易的spring框架

本例子主要模拟的是Spring的IOC功能,不含AOP

首先定义例子用到的entity,dao,service包下的类

Student类

public class Student {private int id;private String name;private int age;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}

StudentDaoImpl类

public class StudentDaoImpl implements StudentDao {@Overridepublic void add(Student stus) {System.out.println("学生保存成功");}}

StudentServiceImpl类

public class StudentServiceImpl implements StudentService {private StudentDao sdao;public void setStudao(StudentDao sdao) {this.sdao = sdao;}@Overridepublic void add(Student stu) {sdao.add(stu);}}

ClassPathXmlApplicationContext容器类

public class ClassPathXmlApplicationContext implements BeanFactory {private Map<String,Object> beans=new HashMap<String,Object>();public ClassPathXmlApplicationContext() throws Exception, IOException {SAXBuilder sb=new SAXBuilder();Document doc=sb.build(this.getClass().getClassLoader().getResourceAsStream("beans.xml"));Element root=doc.getRootElement();List list=root.getChildren("bean");for(int i=0;i<list.size();i++){Element ele=(Element) list.get(i);String id=ele.getAttributeValue("id");String clazz=ele.getAttributeValue("class");Object o=Class.forName(clazz).newInstance();beans.put(id, o);for(Element proele:(List<Element>)ele.getChildren("property")){String name =proele.getAttributeValue("name");String bean=proele.getAttributeValue("bean");Object beanObject=beans.get(bean);String methodName="set"+name.substring(0,1).toUpperCase()+name.substring(1);System.out.println("method name = " + methodName);Method m=o.getClass().getMethod(methodName, beanObject.getClass().getInterfaces()[0]);m.invoke(o, beanObject);}}}@Overridepublic Object getBean(String id) {return beans.get(id);}}

beans.xml

<beans><bean id="studao" class="com.wulijian.daoImpl.StudentDaoImpl"/><bean id="stuService" class="com.wulijian.ServiceImpl.StudentServiceImpl"><property name="studao" bean="studao"/></bean></beans>

测试类

public class Test {public static void main(String[] args) throws IOException, Exception {ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext();  Student stu = new Student();  StudentService service = (StudentService) context.getBean("stuService");  service.add(stu);  }}