spring侵入代码的各种方式整理汇总

spring提供了很多方式更改代码的一些值，虽然非常方便，滥用容易不受控制，对代码阅读，后续维护产生一定的难度，这里整理下方式。

一 修改函数入参

argumentResolver

@Componentpublic class HandlerMethodArgumentResolverDemo implements HandlerMethodArgumentResolver {    @Override    public boolean supportsParameter(MethodParameter methodParameter) {        if (methodParameter != null && methodParameter.getParameterType() == String.class && methodParameter.getParameterIndex() == 1) {            return true;        }        return false;    }

    @Override    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {        System.out.println("HandlerMethodArgumentResolverDemo");        return "set argument by HandlerMethodArgumentResolverDemo";    }}

@SpringBootConfigurationpublic class ConfigDemo extends WebMvcConfigurerAdapter {    @Autowired    IntercepterDemo intercepterDemo;    @Override    public void addInterceptors(InterceptorRegistry registry) {        registry.addInterceptor(intercepterDemo).addPathPatterns("/**");//配置拦截的路径，可以传多个参数        /*registry.addInterceptor(authorityInterceptor).addPathPatterns("/**");*/    }    @Autowired    HandlerMethodArgumentResolverDemo handlerMethodArgumentResolverDemo;    @Override    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {        argumentResolvers.add(handlerMethodArgumentResolverDemo);    }}

二 interceptor

@Componentpublic class IntercepterDemo implements HandlerInterceptor {    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {        response.addHeader("interceptaddhader","preintercepter");        System.out.println("IntercepterDemo preintecepter");        return true;    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {        response.addHeader("interceptaddhader","postintercepter");        if(modelAndView != null){            modelAndView.addObject("addObject");        }        System.out.println("IntercepterDemo postintecepter");    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {        System.out.println("IntercepterDemo afterCompletion");    }}

上一个例子的 ConfigDemo 注册了这个intercepter

三.aop的方式

spring-aop ,aspectJ ,这个比较常用,先不说了

四 listener

普通web工程加listener:

Listener接口分类

1ServletContextListener监听ServletContext对象

> ServletContextAttributeListener监听对ServletContext属性的操作，比如增加、删除、修改

> HttpSessionListener监听Session对象

> HttpSessionActivationListener监听HTTP会话的active和passivate情况，passivate是指非活动的session被写入持久设备（比如硬盘），active相反。

> HttpSessionAttributeListener监听Session中的属性操作

> ServletRequestListener监听Request对象

> ServletRequestAttributeListener监听Requset中的属性操作

定义类 : public class CountListener implements HttpSessionListener

配置 监听器:

1. <listener>
2. <listener-class>web.CountListener</listener-class>
3. </listener>

springboot 配置listener,举两个例子

@WebListenerpublic class ServletRequestListener implements javax.servlet.ServletRequestListener {    public void  requestDestroyed(ServletRequestEvent sre) {        System.out.println("listner "+sre.getServletContext().getAttributeNames().toString());    }}

//仅仅发布服务时被调用一次@WebListenerpublic class ServletContextListenerDemo implements ServletContextListener {    public void contextInitialized(ServletContextEvent sce) {        System.out.println("listner "+sce.getServletContext().getAttributeNames().toString());    }

    public  void contextDestroyed(ServletContextEvent sce) {    }}

@SpringBootApplication@ServletComponentScan(basePackages = "com.learn.filtertest") public class MvntestApplication {    public static void main(String[] strings){        SpringApplication.run(MvntestApplication.class,strings);    }}

五 filter

每个请求只执行一次的filter

@Componentpublic class OncePerRequestFilterDemo extends OncePerRequestFilter {    @Override    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {        httpServletResponse.addHeader("qzltest","yes");        System.out.println("OncePerRequestFilterDemo ,request uri is : " + httpServletRequest.getRequestURI());        filterChain.doFilter(httpServletRequest,httpServletResponse);    }}六 RequestBodyAdvice   ReqponseBodyAdvice

@ControllerAdvicepublic class RequestBodyAdviceDemo implements RequestBodyAdvice {    @Override    public boolean supports(MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {        return true;    }

    @Override    public HttpInputMessage beforeBodyRead(HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) throws IOException {        //httpInputMessage.getBody().        System.out.println("RequestBodyAdviceDemo request body advice beforebodyread " + methodParameter.getMethod().getName());        return httpInputMessage;    }

    @Override    public Object afterBodyRead(Object o, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {        System.out.println("RequestBodyAdviceDemo request body advice afterbodyread " + methodParameter.getMethod().getName());        return o;    }

    @Override    public Object handleEmptyBody(Object o, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {        System.out.println("RequestBodyAdviceDemo request body advice handler empty body " + methodParameter.getMethod().getName());        Class clazz = methodParameter.getParameterType();        if (clazz.equals(String.class)){            return "auto generate";        }        return o;    }}

@ControllerAdvicepublic class ResponseBodyAdviceDemo implements ResponseBodyAdvice {    @Override    public boolean supports(MethodParameter methodParameter, Class aClass) {        return methodParameter.getMethodAnnotations().length >= 1;    }

    @Override    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {        if(serverHttpResponse.getHeaders().containsKey("qzltest")){            System.out.println("ResponseBodyAdviceDemo response contains header qzl ,request uri is : " + serverHttpRequest.getURI());        }        if (o != null && o instanceof String){            return " add by class ResponseFilterDemo , string: "+ (String) o;        }        return o;    }}

原文地址：https://www.cnblogs.com/thinkqin/p/11812082.html