我正在尝试使用Apache Tomcat 7.0.56从Netbeans 8.0.1运行我的Web应用程序，一旦我提交登录表单，我就会收到以下错误：
Firefox can't establish a connection to the server at localhost:8084. - The site could be temporarily unavailable or too busy. Try again in a few moments. - If you are unable to load any pages, check your computer's network connection. - If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.
我的其他应用程序工作得很好，它似乎就是这个。我不知道为什么会发生这种情况。
有人能弄明白出了什么问题吗？
这是我的Apache Tomcat日志：
Using CATALINA_BASE: "C:\Program Files\apache-tomcat-7.0.56"
Using CATALINA_HOME: "C:\Program Files\apache-tomcat-7.0.56"
Using CATALINA_TMPDIR: "C:\Program Files\apache-tomcat-7.0.56\temp"
Using JRE_HOME: "C:\Program Files\Java\jdk1.7.0_40"
Using CLASSPATH: "C:\Program Files\apache-tomcat-7.0.56\bin\bootstrap.jar;C:\Program Files\apache-tomcat-7.0.56\bin\tomcat-juli.jar"
Listening for transport dt_shmem at address: tomcat_shared_memory_id
Dec 11, 2014 1:49:13 PM org.apache.catalina.core.AprLifecycleListener init
INFO: Loaded APR based Apache Tomcat Native library 1.1.31 using APR version 1.4.8.
Dec 11, 2014 1:49:13 PM org.apache.catalina.core.AprLifecycleListener init
INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].
Dec 11, 2014 1:49:14 PM org.apache.catalina.core.AprLifecycleListener initializeSSL
INFO: OpenSSL successfully initialized (OpenSSL 1.0.1h 5 Jun 2014)
Dec 11, 2014 1:49:15 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-apr-8080"]
Dec 11, 2014 1:49:15 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-apr-8009"]
Dec 11, 2014 1:49:15 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 2409 ms
Dec 11, 2014 1:49:15 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Dec 11, 2014 1:49:15 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.56
Dec 11, 2014 1:49:15 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Program Files\apache-tomcat-7.0.56\conf\Catalina\localhost\coursework.xml
Dec 11, 2014 1:49:16 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deployment of configuration descriptor C:\Program Files\apache-tomcat-7.0.56\conf\Catalina\localhost\coursework.xml has finished in 1,706 ms
Dec 11, 2014 1:49:16 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\docs
Dec 11, 2014 1:49:17 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\docs has finished in 265 ms
Dec 11, 2014 1:49:17 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\examples
Dec 11, 2014 1:49:17 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\examples has finished in 759 ms
Dec 11, 2014 1:49:17 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\host-manager
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\host-manager has finished in 231 ms
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\manager
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\manager has finished in 292 ms
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\ROOT
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory C:\Program Files\apache-tomcat-7.0.56\webapps\ROOT has finished in 196 ms
Dec 11, 2014 1:49:18 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-apr-8080"]
Dec 11, 2014 1:49:18 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-apr-8009"]
Dec 11, 2014 1:49:18 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 3599 ms
Dec 11, 2014 1:49:19 PM org.apache.coyote.http11.AbstractHttp11Processor process
INFO: Error parsing HTTP request header
Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.
Dec 11, 2014 1:49:22 PM org.apache.catalina.startup.HostConfig undeploy
INFO: Undeploying context [/coursework]
Dec 11, 2014 1:49:22 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Program Files\apache-tomcat-7.0.56\conf\Catalina\localhost\coursework.xml
Dec 11, 2014 1:49:22 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deployment of configuration descriptor C:\Program Files\apache-tomcat-7.0.56\conf\Catalina\localhost\coursework.xml has finished in 554 ms
Dec 11, 2014 1:49:22 PM org.apache.catalina.util.LifecycleBase start
INFO: The start() method was called on component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/coursework]] after start() had already been called. The second call will be ignored.