因为没有spring的包，所有用配置文件
这里配置application.properties的地址
配置项目路径
1.@AutoWired
2.@Controller
3.@RequestMapping
4.@RequestParam
5.@Service
这里暂时没有定义@ResponseBody
使用大量的反射进行操作
public class DDispatcherServlet extends HttpServlet {
private Properties contextConfig=new Properties();
private List classNames=new ArrayList<>();
private Map ioc=new ConcurrentHashMap<>();
private Map handlerMapping=new ConcurrentHashMap<>();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//6.调用，运行阶段
try {
doDispatcher(req,resp);
} catch (Exception e) {
e.printStackTrace();
resp.getWriter().write("500"+Arrays.toString(e.getStackTrace()));
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//6.调用，运行阶段
try {
doDispatcher(req,resp);
} catch (Exception e) {
e.printStackTrace();
resp.getWriter().write("500"+Arrays.toString(e.getStackTrace()));
}
}
private void doDispatcher(HttpServletRequest req, HttpServletResponse resp) throws IOException, InvocationTargetException, IllegalAccessException {
String url = req.getRequestURI();
//处理成相对路径
String contextPath = req.getContextPath();
url=url.replaceAll(contextPath,"").replaceAll("/+","/");
if (!handlerMapping.containsKey(url)){
resp.getWriter().write("404");
}
Method method = handlerMapping.get(url);
//通过反射拿到method所在class
String beanName =toLowerFirstCase( method.getDeclaringClass().getSimpleName());
Map params = req.getParameterMap();
//获取方法的形参列表
Class[] parameterTypes = method.getParameterTypes();
Object[] paramValues= new Object[parameterTypes.length];
//一维是参数索引，二维是参数注解
Annotation[][] annotations = method.getParameterAnnotations();
for (int i = 0; i < parameterTypes.length; i++) {
Class parameterType = parameterTypes[i];
if (parameterType==HttpServletRequest.class){
paramValues[i]=req;
continue;
}else if (parameterType==HttpServletResponse.class){
paramValues[i]=resp;
continue;
}else{
for (Annotation annotation:annotations[i]){
//获取参数上的注解
DRequestParam requestParam = (DRequestParam) annotation;
if (requestParam instanceof DRequestParam){
String[] mapValue = params.get(requestParam.value());
if (mapValue!=null){
//字符串转化
Object value = convert(parameterType,Arrays.toString(mapValue) );
paramValues[i]=value;
}
}
}
}
}
method.invoke(ioc.get(beanName),paramValues);
}
private Object convert(Class type,String value){
value = value.replaceAll("\[|\]","")
.replaceAll("\s",",");
if (Integer.class==type){
return Integer.valueOf(value);
}
return value;
}
@Override
public void init(ServletConfig config) throws ServletException {
//1.加载配置文件
doLoadConfig(config.getInitParameter("contextConfigLocation"));
// 2.扫描相关类
doScanner(contextConfig.getProperty("scanPackage"));
//3.初始化扫描到的类，并放入ioc中
DoInstance();
//4.完成依赖注入
doAutoWired();
//5.初始化HandlerMapping
initHandlerMapping();
System.out.println("D Spring frame is init");
}
private void initHandlerMapping() {
if (ioc.isEmpty()){
return;
}
Set> entries = ioc.entrySet();
for (Map.Entry entry : entries) {
Class clazz = entry.getValue().getClass();
if (!clazz.isAnnotationPresent(DController.class)){
continue;
}
//保存写在类上的url
String baseUrl="/";
if (clazz.isAnnotationPresent(DController.class)){
DRequestMapping requestMapping = clazz.getAnnotation(DRequestMapping.class);
baseUrl += requestMapping.value();
}
//获取所有public的方法
Method[] methods = clazz.getMethods();
for (Method method : methods) {
if (!method.isAnnotationPresent(DRequestMapping.class)){
continue;
}
DRequestMapping methodMapping = method.getAnnotation(DRequestMapping.class);
//如果出现多个斜杆，替换成一个
String url=(baseUrl+"/"+methodMapping.value()).replaceAll("/+","/");
//放入映射容器
handlerMapping.put(url,method);
System.out.println("url："+url+":"+method.toString());
}
}
}
private void doAutoWired() {
if (ioc.isEmpty()){
return;
}
Set> entries = ioc.entrySet();
for (Map.Entry entry : entries) {
//获得一个对象的所有方法
Field[] fields = entry.getValue().getClass().getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(DAutowired.class)){
DAutowired autowired = field.getAnnotation(DAutowired.class);
String beanName = autowired.value().trim();
//如果注解默认值为空，则根据类型注入
if ("".equals(beanName)){
beanName=field.getType().getName();
}
//赋值
try {
field.setAccessible(true);
field.set(entry.getValue(),ioc.get(beanName));
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
}
}
}
private void DoInstance() {
//初始化,为DI做准备
if (classNames.isEmpty()){return;}
for (String className : classNames) {
try {
Class clazz = Class.forName(className);
//加了注解的类需要初始化,这里只举例几个注解
if (clazz.isAnnotationPresent(DController.class)){
Object instance = clazz.getDeclaredConstructor().newInstance();
//类名首字母小写
String beanName = toLowerFirstCase(clazz.getSimpleName());
ioc.put(beanName,instance);
}else if (clazz.isAnnotationPresent(DService.class)){
DService service = clazz.getAnnotation(DService.class);
//1.自定义beanName
// 获得该注解的默认值
String beanName = service.value();
//2.默认类名首字母小写
if ("".equals(beanName.trim())){
beanName = toLowerFirstCase(clazz.getSimpleName());
}
Object instance = clazz.getDeclaredConstructor().newInstance();
//3.根据类型自动注入,扫描该类的所有接口
for (Class i:clazz.getInterfaces()){
//防止使用相同key名
if (ioc.containsKey(i.getName())){
throw new Exception(i.getName()+"该类实例已存在，请更换名字");
}
ioc.put(i.getName(),instance);
}
}else {
continue;
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
private String toLowerFirstCase(String simpleName) {
char[] chars = simpleName.toCharArray();
//大小写字母ASCII码相差32
if (chars[0]>=65&&chars[0]<=90){
//说明是一个大写字母
chars[0] +=32;
}
return String.valueOf(chars);
}
//扫描相关类
private void doScanner(String scanPackage) {
//转化成文件路径:classpath，注意双亲委派机制
URL url = this.getClass().getClassLoader().getResource(scanPackage.replaceAll("\.","/"));
File classpath = new File(url.getFile());
File[] files = classpath.listFiles();
for (File file : files) {
if (file.isDirectory()){
doScanner(scanPackage+"."+file.getName());
}else {
if (!file.getName().endsWith(".class")){continue;}
//得到完整的类名
String className=(scanPackage+"."+file.getName().replace(".class",""));
//保存到容器中
classNames.add(className);
}
}
}
private void doLoadConfig(String contextConfigLocation) {
InputStream fis=null;
//直接从类路径下找到Spring主配置文件所在路径
//将properties文件放到Properties对象中
fis=this.getClass().getClassLoader().getResourceAsStream(contextConfigLocation);
try {
contextConfig.load(fis);
} catch (IOException e) {
e.printStackTrace();
}finally {
if (null!=fis){
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
