springboot中@component注解的使用實(shí)例

更新時間：2022年03月23日 15:42:22 作者：天蒙蒙亮

這篇文章主要介紹了springboot中@component注解的使用實(shí)例，具有很好的參考價值，希望對大家有所幫助。如有錯誤或未考慮完全的地方，望不吝賜教

@component注解的使用

配置響應(yīng)頭的內(nèi)容。

方式一

直接在攔截器里配置響應(yīng)頭內(nèi)容。

/**
?* 攔截器--用戶身份確認(rèn)。
?*/
public class RestInterceptor implements HandlerInterceptor {?? ?
?? ?private static final Logger log = LoggerFactory.getLogger(RestInterceptor.class);
?? ?private static final String tokenHeader = "Authorization";
?
?? ?/**?
? ? ? ? ?* ?返回值：true表示繼續(xù)流程（如調(diào)用下一個攔截器或處理器）；false表示流程中斷（如登錄檢查失敗），不會繼續(xù)調(diào)用其他的攔截器或處理器，此時我們需要通過response來產(chǎn)生響應(yīng)；?
?? ? */
?? ?public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
?? ??? ?log.info("攔截請求");
?? ??? ?//響應(yīng)頭
?? ??? ?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("調(diào)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){ //非驗(yàn)證API?
//?? ??? ??? ?return true;//跳過驗(yàn)證
//?? ??? ?}
?? ??? ?//驗(yàn)證
//?? ??? ?String token = request.getHeader(tokenHeader);
//?? ??? ?if(token == null || token.equals("")) {
//?? ??? ??? ?log.info("沒有找到token");
//?? ??? ??? ?throw new BusinessException(ResMsg.CODE_TOKEN_NOTFOUND, "沒有找到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")) {//為兼容老版本的接口
//?? ??? ??? ??? ?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("處理中");
?? ?}
?
?? ?public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
?? ??? ??? ?throws Exception {
?? ??? ?if(ex != null) {
?? ??? ??? ?log.error("接口處理異常:"+ex);
?? ??? ??? ?throw ex;
?? ??? ?}
?? ?}
}

方式二

使用@component注解，將普通JavaBean實(shí)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表示繼續(xù)流程（如調(diào)用下一個攔截器或處理器）；false表示流程中斷（如登錄檢查失?。粫^續(xù)調(diào)用其他的攔截器或處理器，此時我們需要通過response來產(chǎn)生響應(yīng)；?
?? ? */
?? ?public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
?? ??? ?log.info("攔截請求");
?? ??? ? ?
?? ??? ?if(request.getMethod().equals("OPTIONS")){
?? ??? ??? ?response.setStatus(204);
?? ??? ??? ?return true;
?? ??? ?}?? ??? ?
?? ??? ?log.info("調(diào)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("處理中");
?? ?}
?
?? ?public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
?? ??? ??? ?throws Exception {
?? ??? ?if(ex != null) {
?? ??? ??? ?log.error("接口處理異常:"+ex);
?? ??? ??? ?throw ex;
?? ??? ?}
?? ?}
}

定義 SimpleCORSFilter.java 類, 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() {}? ??
}

兩種方式都可以完成響應(yīng)。