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

@Component
public 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";
    }
}

@SpringBootConfiguration
public 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

@Component
public 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

@WebListener
public 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
@WebListener
public 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

@Component
public 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

@ControllerAdvice
public 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;
    }
}

@ControllerAdvice
public 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;
    }
}