前言:

前后分离时,我们要定义好统一的接口返回格式
eg:{“code”:0 ,“message”:“成功”,“data”:null}
返回格式与业务不相关且重复构建结果会产生大里冗余代码, 那么该怎么去抽离出来?
可以考虑将包含某些标记的方法或者类的结果进行重写,我们可以使用ResponseBodyAdvice来实现,当然也可作为加密解密的一种实现方式

思路

1.定义标识,可以定义一个注解作为标识

@Target({ElementType.TYPE,ElementType.METHOD})
@Documented
@Retention(RetentionPolicy.RUNTIME)
public @interface WebResponseResultAdvice {

}

2.对Controller或者method打上标识

  @RequestMapping("/webResultAdvice")
    @WebResponseResultAdvice
    public Object testWebResult(String param) {
        return demoService.testGlobalResult(param);
    }

3.请求时判断是否存在该标识,可以利用拦截器

public class ResponseResultInterceptor extends HandlerInterceptorAdapter {
    private final static String WEB_RESULT_BUILD_TAG = "webResultBuildTag";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = (HandlerMethod)handler;
            //获取class
            Class<?> classType = handlerMethod.getBeanType();
            //获取method
            Method method = handlerMethod.getMethod();
            if (classType.isAnnotationPresent(WebResponseResultAdvice.class) ||
                    method.isAnnotationPresent(WebResponseResultAdvice.class)) {
                request.setAttribute(WEB_RESULT_BUILD_TAG,true);
            }
        }
        return true;
    }
}

springboot可以统一配置在mvcconfig中

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        InterceptorRegistration interceptorRegistration = registry.addInterceptor(new ResponseResultInterceptor());
        interceptorRegistration.addPathPatterns("/**");
    }
}

4.对结果重新写入

@ControllerAdvice
public class BaseWebResultHandler implements ResponseBodyAdvice {
    private final static String WEB_RESULT_BUILD_TAG = "webResultBuildTag";

    @Override
    public boolean supports(MethodParameter methodParameter, Class aClass) {
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes)RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = requestAttributes.getRequest();
        Object attribute = request.getAttribute(WEB_RESULT_BUILD_TAG);
        return attribute == null ? false:true;
    }

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        return JSON.toJSONString(WebResultDto.buildSuccessResult(o));
    }
}