spring boot中 @component的注解的使用案例

配置响应头的内容。

方式一： 直接在拦截器里配置响应头内容。

/**
 * 拦截器--用户身份确认。
 */
public class RestInterceptor implements HandlerInterceptor {
	
	private static final Logger log = LoggerFactory.getLogger(RestInterceptor.class);
	private static final String tokenHeader = "Authorization";

	/** 
         *  返回值：true表示继续流程（如调用下一个拦截器或处理器）；false表示流程中断（如登录检查失败），不会继续调用其他的拦截器或处理器，此时我们需要通过response来产生响应； 
	 */
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		log.info("拦截请求");
		//响应头
		response.setHeader("Access-Control-Allow-Origin", "*");
		response.setHeader("Access-Control-Allow-Headers", "x-requested-with,content-type,authorization");
		response.setHeader("Access-Control-Allow-Methods", "POST,GET,OPTIONS");
		
		if(request.getMethod().equals("OPTIONS")){
			response.setStatus(204);
			return true;
		}		
		log.info("调用接口:method=" +request.getParameter("method")+",params="+JSON.toJSONString(request.getParameterMap()));
		
//		HandlerMethod handlerMethod = (HandlerMethod)handler;
//		RequestAuth requestAuth = handlerMethod.getMethodAnnotation(RequestAuth.class);
//		if(requestAuth!=null && requestAuth.auth()==false){ //非验证API 
//			return true;//跳过验证
//		}
		//验证
//		String token = request.getHeader(tokenHeader);
//		if(token == null || token.equals("")) {
//			log.info("没有找到token");
//			throw new BusinessException(ResMsg.CODE_TOKEN_NOTFOUND, "没有找到token");
//		} else {
//			JWSObject jwsObject = JWSObject.parse(token);
//			Payload payload = jwsObject.getPayload();
//			JSONObject obj = payload.toJSONObject();
			
//			String roleNames = String.valueOf(obj.get("roleNames"));
//			Authentication auth = new Authentication();
//			if(obj.containsKey("platformId")) {
//				Long platformId = Long.valueOf(String.valueOf(obj.get("platformId")));
//				auth.setPlatformId(platformId);
//			}
//			if(obj.containsKey("userid")) {
//				Long userId = Long.valueOf(String.valueOf(obj.get("userid")));
//				auth.setUserId(userId);
//			}
//			if(obj.containsKey("orgId")) {
//				Long orgId = Long.valueOf(String.valueOf(obj.get("orgId")));
//				auth.setOrgId(orgId);
//			}
//			if(obj.containsKey("orgid")) {//为兼容老版本的接口
//				String orgid = String.valueOf(obj.get("orgid"));
//				orgid = orgid.replace(",", "");
//				Long orgId = Long.valueOf(orgid);
//				auth.setOrgId(orgId);
//			}
//			auth.setRoleNames(roleNames);
//			SecurityContext.setContext(auth);
//			JwtUtil.verify(jwsObject);
//		}
		return true;
	}

	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		//log.info("处理中");
	}

	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		if(ex != null) {
			log.error("接口处理异常:"+ex);
			throw ex;
		}
	}
}

方式二： 使用 @component注解，将普通JavaBean实例化到spring容器中。

public class RestInterceptor implements HandlerInterceptor {
	
	private static final Logger log = LoggerFactory.getLogger(RestInterceptor.class);
	private static final String tokenHeader = "Authorization";

	/** 
         * 返回值：true表示继续流程（如调用下一个拦截器或处理器）；false表示流程中断（如登录检查失败），不会继续调用其他的拦截器或处理器，此时我们需要通过response来产生响应； 
	 */
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
		log.info("拦截请求");
		  
		if(request.getMethod().equals("OPTIONS")){
			response.setStatus(204);
			return true;
		}		
		log.info("调用接口:method=" +request.getParameter("method")+",params="+JSON.toJSONString(request.getParameterMap()));
		 
		return true;
	}

	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		//log.info("处理中");
	}

	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		if(ex != null) {
			log.error("接口处理异常:"+ex);
			throw ex;
		}
	}
}

定义 SimpleCORSFilter.java 类, 使用@component注解

@Component
public class SimpleCORSFilter implements Filter {
    
	public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,content-type,authorization");
        chain.doFilter(req, res);
    }

    public void init(FilterConfig filterConfig) {}

    public void destroy() {}
    
}

两种方式都可以完成响应。