如何在 Clojure 中使用 getInputStream() 获取 POST 请求数据。我在 Reflector 中收到 NullPointerException

Question

这是我从电子邮件中获取消息的功能：

    (defn parse-message [request]
    (let [session (javax.mail.Session/getDefaultInstance (java.util.Properties.) nil)
          msg (javax.mail.internet.MimeMessage. session (.getInputStream (:request request)))])

当我 运行 这时我得到异常：

java.lang.NullPointerException
at clojure.lang.Reflector.invokeNoArgInstanceMember(Reflector.java:301)
at clojure_gae.core$parse_message.invoke(core.clj:161)
at clojure_gae.core$fn__2038.invoke(core.clj:230)
at compojure.core$make_route$fn__1769.invoke(core.clj:113)
at compojure.core$wrap_route_middleware$fn__1765.invoke(core.clj:103)
at compojure.core$if_route$fn__1744.invoke(core.clj:41)
at compojure.core$if_method$fn__1736.invoke(core.clj:27)
at compojure.core$routing$fn__1775.invoke(core.clj:127)
at clojure.core$some.invoke(core.clj:2515)
at compojure.core$routing.doInvoke(core.clj:127)
at clojure.lang.RestFn.applyTo(RestFn.java:139)
at clojure.core$apply.invoke(core.clj:626)
at compojure.core$routes$fn__1779.invoke(core.clj:132)
at clojure.lang.Var.invoke(Var.java:379)
at clojure_gae.listener$_contextInitialized$fn__11.invoke(listener.clj:1)
at ring.util.servlet$make_service_method$fn__2091.invoke(servlet.clj:126)
at clojure_gae.servlet$_service.invoke(servlet.clj:1)
at clojure_gae.servlet.service(Unknown Source)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:128)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:50)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:511)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

任何人都可以告诉我如何解决这个问题以及为什么我会收到此异常。我同时导入了 Java.io InputStream 和 OutStream。将收到的电子邮件中的消息解析为 post 请求的代码或任何其他方式是否有任何问题。谢谢你的帮助。

Answer 1

假设request是一个Ring请求映射，你可以使用(slurp (:body request))读取POST请求体。详情请参阅 https://github.com/ring-clojure/ring/wiki/Concepts#requests。