使用BeanFactory实现创建对象

/**
 *beans.properties文件的内容(位于与src平级的config资源包下)
 */
Student=com.xxx.generic.demo.Student
Teacher=com.xxx.generic.demo.Teacher
 
/**
 *BeanFactory类的参考代码
 */
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
 
public class BeanFactory {
 private BeanFactory() {
 }
 
 private static Map<String, String> beans = new HashMap<>();
 static {
 InputStream is = BeanFactory.class.getClassLoader().getResourceAsStream("beans.properties");
 Properties prop = new Properties();
 try {
  prop.load(is);
  Enumeration<String> keys = (Enumeration<String>) prop.propertyNames();
  while (keys.hasMoreElements()) {
  String key = keys.nextElement();
  String value = prop.getProperty(key);
  beans.put(key, value);
  }
 } catch (Exception e) {
  e.printStackTrace();
 } finally {
  if (is != null) {
  try {
   is.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
  }
 }
 }
 
 public static <T> T getBean(Class<T> clazz) {
 T t = null;
 String className = clazz.getSimpleName();
 Set<String> keys = beans.keySet();
 for (String key : keys) {
  if (key.equals(className)) {
  String value = beans.get(key);
  try {
   t = (T) Class.forName(value).newInstance();
  } catch (Exception e) {
   e.printStackTrace();
  }
  break;
  }
 }
 return t;
 }
}
 
/**
 *BeanTest类参考代码
 */
public class BeanTest {
 public static void main(String[] args) {
 Student s = BeanFactory.getBean(Student.class);
 System.out.println(s + ":我是" + s.getClass().getSimpleName() + "的一个对象。");
 Teacher t = BeanFactory.getBean(Teacher.class);
 System.out.println(t + ":我是" + t.getClass().getSimpleName() + "的一个对象。");
 }
}