基于之前的添加pom文件

    <!--反射工具包--><dependency><groupId>org.reflections</groupId><artifactId>reflections</artifactId><version>0.9.12</version></dependency><!--工具包--><dependency><groupId>org.apache.commons</groupId><artifactId>commons-lang3</artifactId><version>3.10</version></dependency>

配置文件

basePackage=com.liu

注解

/*** @Description 用于注入一个对象* @ClassName Autowired 类名* @Author 刘楠* @date 2020.06.30*/
@Target({ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Autowired {/*** 依赖必须存在,不然就报错* @return*/boolean required() default true; //true就必须注入
}/*** @Description 用于标记一个类* @ClassName Service 类名* @Author 刘楠* @date 2020.06.30*/
@Documented
@Target(ElementType.TYPE) //只能用在类上
@Retention(RetentionPolicy.RUNTIME)
public @interface Service {/*** 类的id名称* @return*/String value() default "";//可以有也可以没有
}
@Target({ElementType.TYPE}) //类上
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Transactional {/*** 这个给个默认值也可以给空,工厂里获取也可以 这个省个事* @return*/String value() default "transactionManager"; //默认事务管理器
}

在dao service TransactionManager ProxyFactory修改使用以上注解

• dao

@Service("accountDao")
public class JdbcAccountDaoImpl implements AccountDao {@Autowiredprivate ConnectionUtils connectionUtils;

• service

@Service("transferService")
@Transactional
public class TransferServiceImpl implements TransferService {// 最佳状态@Autowiredprivate AccountDao accountDao;

• TransactionManager

@Service("transactionManager")
public class TransactionManager {@Autowiredprivate ConnectionUtils connectionUtils;

• ProxyFactory

@Service("proxyFactory")
public class ProxyFactory {@Autowiredprivate TransactionManager transactionManager;public void setTransactionManager(TransactionManager transactionManager) {this.transactionManager = transactionManager;}

新增一个工具类

public class PropertiesUtils {private static Properties props = new Properties();public static Properties getProperties(String path) {InputStream in = PropertiesUtils.class.getClassLoader().getResourceAsStream(path);try {props.load(in);} catch (IOException e) {e.printStackTrace();}return props;}}

修改 BeanFactory原来改名BeanFactoryOld不用,新建BeanFactory

public class BeanFactory {private static Map<String, Object> map = new ConcurrentHashMap<>();  // 存储对象//默认要扫描的包,可通过配置文件来 如果配置文件中为空就使用这个private static String basePackage = "com.liu";private static String basePackageKey = "basePackage";static {try {/*** 1.扫描指定包下的所有类,获取指定注解的类的集合* 2.使用反射创建对象* 3.获取Service注射标记的类* 4.判断注解value是否有值,有就放入容器* 5.无值 如果有是类就获取类名称,并放入容器* 6.无值情况下获取接口的名称,如果无值同时接口数量大于1就抛出异常* 7.无值只有一个接口,获取接口名称放入容器* 8.初始化完成*/doInitializationBean();/*** 判断是否有Autowired,*/doAutowired();/*** Transactional注解标记的类*/doTransactional();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}/*** 初始化Bean,并放入容器中* @throws InstantiationException* @throws IllegalAccessException*/private static void doInitializationBean() throws InstantiationException, IllegalAccessException {//1.加载配置因为文件Properties properties = PropertiesUtils.getProperties("base.properties");String property = properties.getProperty(basePackageKey);//如果配置文件中没有,就用默认的if (StringUtils.isBlank(property)) {property = basePackage;}//2.使用反射工具类获取所有带Service注解的类Reflections reflections = new Reflections(property);//获取所有Service注解的类Set<Class<?>> classSet = reflections.getTypesAnnotatedWith(Service.class);//3. 通过反射实实例化for (Class<?> clazz : classSet) {//实例化通过无参数构造Object newInstance = clazz.newInstance();//获取注解Service annotation = clazz.getAnnotation(Service.class);//获取注解中的值if(StringUtils.isBlank(annotation.value())) { //注解没有值//获取接口类Class<?>[] interfaces = clazz.getInterfaces();if (interfaces.length > 1) { //判断接口数量是否>1throw new RuntimeException("该有多个父接口,并没有指定名称,请使用Service注解指定名称");}if (interfaces.length == 0) { //接口数量为0，没有接口//没有接口就是个类获取类名称String simpleName = clazz.getSimpleName();//首字母小写String key = StringUtils.uncapitalize(simpleName);//放入容器中map.put(key,newInstance);} else {//接口数量为1//接口名称String simpleName = interfaces[0].getSimpleName();//首字母小写String key = StringUtils.uncapitalize(simpleName);//放入容器中map.put(key,newInstance);}}else {//注解中有值//4.将类放入容器中String id = annotation.value();//首字母小写String key = StringUtils.uncapitalize(id);//放入容器中map.put(key,newInstance);}}}/*** 注入*/private static void doAutowired() {try {//从容器中获取循环判断for(Map.Entry<String,Object> entry:map.entrySet()){//1.获取创建的对象String objKey = entry.getKey();Object value = entry.getValue();//2.获取对象的类Class clazz =value.getClass();//获取所有属性字段Field[] fields = clazz.getDeclaredFields();//循环处理for (Field field : fields) {//3.判断是否有Autowired注解if(field.isAnnotationPresent(Autowired.class)&& field.getAnnotation(Autowired.class).required()){//4.如果是有Autowired并且值是true,就从容器中去获取对象String simpleName = field.getType().getSimpleName();//5.将首字母小写String key = StringUtils.uncapitalize(simpleName);//获取要注入的对象Object o = map.get(key);//没有就异常if(o==null){throw new RuntimeException(simpleName+"依赖的对象不存在 是null");}//获取这个类的方法Method[] methods = clazz.getMethods();for (Method method : methods) {//6.找到对应字段set方法if(method.getName().equalsIgnoreCase("set"+simpleName)){//7.执行setter方法赋值method.invoke(value, o);}}}}/*** 为什么不在这里做事务,因为事务代理工厂,也需要注入,可能没有完成初始完成,放在下一轮中都实例和注入完成后,再代理* public class ProxyFactory {**     @Autowired*     private TransactionManager transactionManager;*///8.重新放入容器中map.put(objKey, value);}} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}/*** 事务代理*/private static void doTransactional() {for(Map.Entry<String,Object> entry:map.entrySet()) {//1.获取创建的对象String key = entry.getKey();Object value = entry.getValue();//2.获取属性Class clazz = value.getClass();//3.判断当前对象的类是否有Transactionalif(clazz.isAnnotationPresent(Transactional.class)){//4.有这个注解说明要开启事务,获取代理工厂ProxyFactory proxyFactory = BeanFactory.getBean("proxyFactory", ProxyFactory.class);//5.判断 这个对像是否有实现接口Object proxyObj=null;Class[] interfaces = clazz.getInterfaces();//判断有没有接口if(interfaces!=null&&interfaces.length>0){//6.有接口使用jdkproxyObj = proxyFactory.getJdkProxy(value);}else{//7.就是个类使用cglibproxyObj = proxyFactory.getCglibProxy(value);}//8.重新放入容器中 将代理对象放入map.put(key, proxyObj);//10.完成代理}}}public static  Object getBean(String id) {return map.get(id);}public static  <T> T getBean(String id,Class<T> clazz) {return (T)map.get(id);}}

修改servlet

public class TransferServlet extends HttpServlet {/*** 通过工厂获取Service*/private TransferService transferService = BeanFactory.getBean("transferService",TransferService.class) ;

修改完成