我正在使用Spring Boot Filters，并且要求在我的Filter中使用我的一个服务。
以下是我正在使用的代码：
@WebFilter(urlPatterns = {"/getDocs" })
public class AuthenticationFilter implements Filter{
private static Logger logger = Logger.getLogger(AuthenticationFilter.class);
@Autowired
private UserVerificationService userVerificationService;
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest arg0, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
logger.info("checking token in filter");
HttpServletRequest request = (HttpServletRequest) arg0;
DocVerificationRequestWrapper myRequestWrapper = new DocVerificationRequestWrapper((HttpServletRequest) request);
String body = myRequestWrapper.getBody();
logger.info("body = "+body);
Token token = null;
try {
JSONObject jsonObj = new JSONObject(body);
JSONObject tokenObj = (JSONObject) jsonObj.get("token");
Gson gson = new Gson();
token = gson.fromJson(tokenObj.toString(), Token.class);
logger.info("Got Token Object = "+token);
logger.info(" Token = "+token.get_id());
logger.info(" Token Access Token = "+token.getAccessToken());
logger.info(" Token Role Id = "+token.getRoleId());
if(null != token) {
String verStatus = userVerificationService.verifyUser(token);
logger.info("verStatus = "+verStatus);
if(verStatus != null && verStatus.equalsIgnoreCase("success"))
chain.doFilter(request, response);
else
logger.error("Invalid token");
}else {
logger.error("token missing.");
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
}
我解析了RequestWrapper返回的正文并将其转换为令牌对象。但是当从UserVerificationService类调用verifyUser方法时，我得到了空指针异常，它声明UserVerificationService bean没有初始化。
这是我得到的异常堆栈跟踪：
15:31:38.017 [http-nio-8080-exec-3] INFO c.c.d.filters.AuthenticationFilter - Got Token Object = com.ct.docverification.model.Token@5fc79544
15:31:38.017 [http-nio-8080-exec-3] INFO c.c.d.filters.AuthenticationFilter - Token = null
15:31:38.017 [http-nio-8080-exec-3] INFO c.c.d.filters.AuthenticationFilter - Token Access Token = f2830dee-7f5d-44c5-ac7b-e7a32f8baa9f
15:31:38.017 [http-nio-8080-exec-3] INFO c.c.d.filters.AuthenticationFilter - Token Role Id = [1.0]
15:31:38.022 [http-nio-8080-exec-3] ERROR o.s.boot.web.support.ErrorPageFilter - Forwarding to error page from request [/getDocs] due to exception [null]
java.lang.NullPointerException: null
at com.ct.docverification.filters.AuthenticationFilter.doFilter(AuthenticationFilter.java:68)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:115)
at org.springframework.boot.web.support.ErrorPageFilter.access$000(ErrorPageFilter.java:59)
at org.springframework.boot.web.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:90)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
我是否需要在弹簧启动配置中单独注册过滤器？或任何建议，如何解决这个问题？
答案 0 :(得分：0)
我通过使用webapplicationcontext和servletContext懒惰初始化userService解决了这个问题，如下所示：
public void doFilter(ServletRequest arg0, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
logger.info("checking token in filter");
HttpServletRequest request = (HttpServletRequest) arg0;
DocVerificationRequestWrapper myRequestWrapper = new DocVerificationRequestWrapper((HttpServletRequest) request);
String body = myRequestWrapper.getBody();
Token token = null;
try {
JSONObject jsonObj = new JSONObject(body);
JSONObject tokenObj = (JSONObject) jsonObj.get("token");
Gson gson = new Gson();
token = gson.fromJson(tokenObj.toString(), Token.class);
if(null != token) {
//here initialising the userVerificationService
if(userVerificationService==null){
ServletContext servletContext = request.getServletContext();
WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
userVerificationService = webApplicationContext.getBean(UserVerificationService.class);
}
String verStatus = userVerificationService.verifyUser(token);
logger.info("verStatus = "+verStatus);
if(verStatus != null && verStatus.equalsIgnoreCase("success")) {
chain.doFilter(request, response);
}else
logger.error("Invalid token");
}else {
logger.error("token missing.");
}
} catch (JSONException e) {
logger.error("exception in authetication filter " + e);
}
}