使用java简单实现的一个Spring框架（pom.xml仅包含Servlet jar包依赖）

package org.chengxi.mvnframework.servlet; import org.chengxi.mvnframework.annotation.*; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.lang.annotation.Annotation; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.net.URL; import java.util.*; import java.util.regex.Matcher; import java.util.regex.Pattern; class Handler{ //保存方法对应的实例 protected Object controller; //保存映射的方法 protected Method method; protected Pattern pattern; //保存方法的参数顺序 protected Map<String, Integer> paramIndexMapping; protected Handler(Object controller, Method method, Pattern pattern){ this.controller = controller; this.method = method; this.pattern = pattern; paramIndexMapping = new HashMap<String, Integer>(); putParamIndexMapping(method); } //提取方法中加了@RequestParam注解的参数 public void putParamIndexMapping(Method method){ //提取方法中加了注解的参数 Annotation[][] pa = method.getParameterAnnotations(); for(int i=0; i<pa.length; i++){ for(Annotation a: pa[i]){ if(a instanceof RequestParam){ String paramName = ((RequestParam) a).value(); if(!"".equals(paramName)){ paramIndexMapping.put(paramName,i); } } } } //提取方法中的resp和req参数 Class<?>[] paramsTypes = method.getParameterTypes(); for(int i=0; i<paramsTypes.length; i++){ Class<?> type = paramsTypes[i]; if(type == HttpServletRequest.class || type == HttpServletResponse.class){ paramIndexMapping.put(type.getName(), i); } } } } public class DispatcherServlet extends HttpServlet { private Properties p = new Properties(); private List<String> classNames = new ArrayList<String>(); private Map<String, Object> ioc = new HashMap<String, Object>(); private List<Handler> handlerMapping = new ArrayList<Handler>(); @Override public void init(ServletConfig config) throws ServletException { //获取属性文件，类似于获取application.xml文件所在路径 String application = config.getInitParameter("contextConfigLocation"); //1.加载配置文件 try { doLoadConfig(application); } catch (IOException e) { e.printStackTrace(); } //扫描配置文件中描述的相关的所有类 doScanner(p.getProperty("scanPackage")); //3.实例化所有被扫描到的类并且存放到IOC容器中（自己实现容器） try { doInstance(); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } //4.依赖注入，DI从IOC容器中找到加上了@Autowired注解的属性并找到其在IOC容器中对应的实例 try { doAutowired(); } catch (IllegalAccessException e) { e.printStackTrace(); } //5.把在@Controller中加了@RequestMapping注解的方法和URL构造成一个对应关系map initHandlerMapping(); System.out.println(ioc); System.out.println(handlerMapping); System.out.println(classNames); } @Override public void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req,resp); } //6.等待用户请求，根据url找到对应的method，通过反射机制进行调用并执行返回响应 @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { try { doDispatcher(req, resp); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } } private void doLoadConfig(String location) throws IOException { InputStream is = this.getClass().getClassLoader(). getResourceAsStream(location); p.load(is); if(null != is){ is.close(); } } private void doScanner(String packageName){ URL url = this.getClass().getClassLoader().getResource("/" + packageName.replaceAll("\\.","/")); File dir = new File(url.getFile()); for(File f: dir.listFiles()){ if(f.isDirectory()){ doScanner(packageName + "." + f.getName()); } else{ classNames.add(packageName + "." + f.getName().replace(".class","").trim()); } } } private void doInstance() throws ClassNotFoundException, IllegalAccessException, InstantiationException { if(classNames.isEmpty()){ return ; } for(String className: classNames){ Class<?> clazz = Class.forName(className); //只初始化controller容器和service容器 if(clazz.isAnnotationPresent(Controller.class)){ //默认首字母小写称为beanName String beanName = lowerFirst(clazz.getSimpleName()); ioc.put(beanName, clazz.newInstance()); } else if(clazz.isAnnotationPresent(Service.class)){ //第一种形式：默认首字母小写 //第二种形式：注解自己提供名字（优先） //第三种形式：利用接口本身全称作为key，其对应实现类作为值 Service service = clazz.getAnnotation(Service.class); String beanName = service.value(); Object instance = clazz.newInstance(); //注解本身提供名字@service("sss") if(!"".equals(beanName.trim())){ ioc.put(beanName, instance); continue; } Class<?>[] interfaces = clazz.getInterfaces(); for(Class<?> inter: interfaces){ ioc.put(inter.getName(), instance); } } } } private void doAutowired() throws IllegalAccessException { if(ioc.isEmpty()){ return; } for(Map.Entry<String, Object> entry: ioc.entrySet()){ //获取所有字段 Field[] fields = entry.getValue().getClass().getDeclaredFields(); for(Field field: fields){ if(!field.isAnnotationPresent(Autowired.class)){ continue; } Autowired autowired = field.getAnnotation(Autowired.class); String beanName = autowired.value().trim(); if("".equals(beanName)){ beanName = field.getType().getName(); } //即使是private也要进行强制注入 field.setAccessible(true); //开始赋值 field.set(entry.getValue(), io