Simulate Spring framework and spring framework

Simulate Spring framework and spring framework

BeanFactory

1 package com.bjsxt.spring;2 3 public interface BeanFactory {4     public Object getBean(String name);5 }

ClassPathXmlApplicationContext

1 package com. bjsxt. spring; 2 3 import java. lang. reflect. method; 4 import java. util. hashMap; 5 import java. util. list; 6 import java. util. map; 7 8 import org. jdom. document; 9 import org. jdom. element; 10 import org. jdom. input. SAXBuilder; 11 12 public class ClassPathXmlApplicationContext implements BeanFactory {13 private Map <String, Object> beans = new HashMap <String, Object> (); 14 15 public ClassPathXmlApplicationContext () throws Exception {16 SAXBuilder sb = new SAXBuilder (); 17 Document doc = sb. build (this. getClass (). getClassLoader (). getResourceAsStream ("beans. xml "); 18 Element root = doc. getRootElement (); // get the root element 19 List list = root. getChildren ("bean"); // obtain all elements named bean 20 for (int I = 0; I <list. size (); I ++) {21 Element element = (Element) list. get (I); 22 String id = element. getAttributeValue ("id"); 23 String clazz = element. getAttributeValue ("class"); 24 System. out. println (id + ":" + clazz); 25 Object o = Class. forName (clazz ). newInstance (); 26 beans. put (id, o); 27 28 for (Element propertyElement: (List <Element>) element. getChildren ("property") {29 String name = propertyElement. getAttributeValue ("name"); // userDAO30 String bean = propertyElement. getAttributeValue ("bean"); // u31 Object beanObject = beans. get (bean); // UserDAOImpl instance32 33 String methodName = "set" + name. substring (0, 1 ). toUpperCase () + name. substring (1); 34 System. out. println ("method name =" + methodName); 35 36 Method m = o. getClass (). getMethod (methodName, beanObject. getClass (). getInterfaces () [0]); 37 m. invoke (o, beanObject); 38} 39} 40} 41 42 public Object getBean (String name) {43 return beans. get (name); 44} 45 46}

Beans. xml

1 <beans>2     <bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl"></bean>3     <bean id="userService" class="com.bjsxt.service.UserService">4         <property name="userDAO" bean="u"></property>5     </bean>6 </beans>

UserDAO

1 package com.bjsxt.dao;2 3 import com.bjsxt.model.User;4 5 public interface UserDAO {6     public void save(User u);7 }

UserDAOImpl

 1 package com.bjsxt.dao.impl; 2  3 import com.bjsxt.dao.UserDAO; 4 import com.bjsxt.model.User; 5  6 public class UserDAOImpl implements UserDAO{ 7  8     public void save(User u) { 9         System.out.println("a user saved!");10     }11 12 }

Test class:

 1 package com.bjsxt.service; 2  3 import org.junit.Test; 4  5 import com.bjsxt.model.User; 6 import com.bjsxt.spring.BeanFactory; 7 import com.bjsxt.spring.ClassPathXmlApplicationContext; 8  9 public class UserServiceTest {10 11     @Test12     public void testAddUser() throws Exception {13         BeanFactory factory = new ClassPathXmlApplicationContext();14         15         UserService service = (UserService)factory.getBean("userService");16         User u = new User();17         service.addUser(u);18     }19 20 }

Code link: http://pan.baidu.com/s/1eSoYu8i password: gtj2

Jar package:

Junit link: http://pan.baidu.com/s/1kVFS8lx password: mkh3

Jdom link: http://pan.baidu.com/s/1c1X15Xu password: 9vpi