springboot中@component注解的使用实例

springboot中@component注解的使用实例

目录@component注解的使用方式一方式二@component注解有什么作用用一句话概括

@component注解的使用

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 handlhttp://erMethod = (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,

ModeVtUPLpINOnlAndView 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 VtUPLpINOn{

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。

@component注解有什么作用

用一句话概括

被@Component注解标识的类，会被纳入Spring容器中统一管理，好处是什么？一句话概括：你不用自己new了！

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