SpringMvc拦截器和手写模拟SpringMvc工作流程源码详解

@Configuration
public class MyConfiguration implements WebMvcConfigurer {
    @Bean
    public LoginInterceptor loginInterceptor(){
        return new LoginInterceptor();
    }
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/test1");
    }
}

@WebFilter("/*")
public class WebTestFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("过滤器前进");
        chain.doFilter(request,response);
        System.out.println("过滤器返回");
    }
    @Override
    public void destroy() {
    }
}

 <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
    </dependency>
    <!--       解析xml文件-->
    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.9</version>
    </dependency>

private ApplicationContext applicationContext; //Spring容器
    @Override
    public void init() throws ServletException {
        String contextConfigLocation = this.getServletConfig().getInitParameter("contextConfigLocation"); //这里获取Web.xml文件中的contextConfigLocation参数，这里为classpath:springmvc.xml。
        applicationContext = new ApplicationContext(contextConfigLocation);//这里为创建Spring容器，从Springmvc.xml文件中读取base-package中的包路径，这里Spring容器会扫描这里的包路径并且生成Controller类型的Bean.
        applicationContext.refresh();
        initHandleMappinng(applicationContext);
    }

  public void initHandleMappinng(ApplicationContext applicationContext){
        if(applicationContext.beanDefinitionConcurrentHashMap.size()==0){
            throw new RuntimeException("Spring容器为空");
        }
        for (Map.Entry<String, BeanDefinition> stringBeanDefinitionEntry : applicationContext.beanDefinitionConcurrentHashMap.entrySet()) {
            Class clazz = stringBeanDefinitionEntry.getValue().getClazz();
            for (Method declaredMethod : clazz.getDeclaredMethods()) {
                boolean annotationPresent = declaredMethod.isAnnotationPresent(RequestMapping.class);
                if(annotationPresent==true){
                    String value = declaredMethod.getAnnotation(RequestMapping.class).value();
                    MyHandle myHandle=new MyHandle(value,declaredMethod,clazz);
                    myHandleList.add(myHandle);
                }
            }
        }
    }

public void excuteDispatch(HttpServletRequest request,HttpServletResponse response){
        MyHandle handle = getHandle(request);
        if(handle==null){
            try {
                response.getWriter().print("404");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        else {
            Method method = handle.getMethod();
            Class<?>[] parameterTypes = method.getParameterTypes();
            Object[] params=new Object[parameterTypes.length];
            Map<String, String[]> parameterMap = request.getParameterMap();
            for (Map.Entry<String, String[]> stringEntry : parameterMap.entrySet()) {
                String key = stringEntry.getKey();
                String value = stringEntry.getValue()[0];
                int i = GetRequestParams(method, key);
                if(i>=0)
                    params[i]=value;
                else {
                    //反射获取的是arg0，官方这里用的不是反射机制
                }
            }
            try {
                Object invoke = method.invoke(handle.getClazz().newInstance(), params);
                PrintWriter writer = response.getWriter();
                writer.print(invoke);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InvocationTargetException e) {
                e.printStackTrace();
            } catch (InstantiationException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

@Controller("mycontroller")
public class MyController {
    @RequestMapping("/test")
    public String test(@RequestParam("name") String name, HttpServletResponse response){
        return name;
    }
}