IntelliJ IDEA 无法解析导入 javax.servlet.*;

Question

所以我让我的项目运行良好，我决定安装一个新的硬盘驱动器 （SSD），现在我无法让它正常运行。

我正在使用 Intellij，并且所有这些导入都有问题。

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

他们说无法解析符号。

在我的web.xml中，我也有这个。

<filter>
    <filter-name>LoginFilter</filter-name>
    <filter-class>com.mkyong.LoginFilter</filter-class>
</filter>

它指出

com.mkyong.LoginFilter is not assignable to javax.servlet.Filter

我将包括我的网络.xml以防万一有人需要它。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
id="WebApp_ID" version="2.5">

<display-name>JavaServerFaces</display-name>

<resource-ref>
<description>MySQL Datasource example</description>
<res-ref-name>jdbc/mkyongdb</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>


<!-- Change to "Production" when you are ready to deploy -->
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>

<!-- Welcome page -->
<welcome-file-list>
<welcome-file>faces/default.xhtml</welcome-file>
</welcome-file-list>

<!-- JSF mapping -->
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>

  <!-- Map these files with JSF -->
 <servlet-mapping>
  <servlet-name>Faces Servlet</servlet-name>
  <url-pattern>/faces/*</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
   <servlet-name>Faces Servlet</servlet-name>
   <url-pattern>*.jsf</url-pattern>
 </servlet-mapping>

<servlet-mapping>
  <servlet-name>Faces Servlet</servlet-name>
  <url-pattern>*.faces</url-pattern>
</servlet-mapping>

<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.xhtml</url-pattern>
</servlet-mapping>

<filter>
    <filter-name>LoginFilter</filter-name>
    <filter-class>com.mkyong.LoginFilter</filter-class>
</filter>
<!-- Set the login filter to secure all the pages in the /secured/* path of the application  -->
<filter-mapping>
    <filter-name>LoginFilter</filter-name>
    <url-pattern>/secured/*</url-pattern>
</filter-mapping>

<!-- By default go to secured welcome page -->
<welcome-file-list>
    <welcome-file>secured/welcome.xhtml</welcome-file>
</welcome-file-list>

</web-app>

这就是我现在犯的错误。

   javax.servlet.ServletException: Servlet.init() for servlet Faces Servlet threw exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:534)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2381)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2370)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)
root cause

java.lang.IllegalStateException: Application was not properly initialized at startup, could not    find Factory: javax.faces.context.FacesContextFactory
javax.faces.FactoryFinder$FactoryManager.getFactory(FactoryFinder.java:800)
javax.faces.FactoryFinder.getFactory(FactoryFinder.java:302)
javax.faces.webapp.FacesServlet.init(FacesServlet.java:186)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:534)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2381)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2370)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)

起初我也在使用 apache tomcat 8，然后我认为这可能是问题所在，我将其更改为 7 然后更改为 6。如果您需要其他任何内容，请告诉我！

这是POM.xml根据要求。

  <project xmlns="http://maven.apache.org/POM/4.0.0" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
 http://maven.apache.org/maven-v4_0_0.xsd">

 <modelVersion>4.0.0</modelVersion>
 <groupId>com.mkyong.common</groupId>
 <artifactId>JavaServerFaces</artifactId>
 <packaging>war</packaging>
 <version>1.0-SNAPSHOT</version>
 <name>JavaServerFaces Maven Webapp</name>
 <url>http://maven.apache.org</url>

<repositories>
 <repository>
   <id>java.net.m2</id>
   <name>java.net m2 repo</name>
   <url>http://download.java.net/maven/2</url>
 </repository>
</repositories>

<dependencies>

  <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-web</artifactId>
      <version>3.2.5.RELEASE</version>
  </dependency>

<!-- MySQL database driver -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.9</version>
</dependency>

<!-- Spring framework --> 
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring</artifactId>
    <version>2.5.6</version>
</dependency>

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>2.5.6</version>
</dependency>


<!-- For Servlet Container like Tomcat -->
<!-- http://download.java.net/maven/2 -->
<dependency>
  <groupId>com.sun.faces</groupId>
  <artifactId>jsf-api</artifactId>
  <version>2.1.0-b03</version>
</dependency>



<!-- EL 2.2 to support method parameter in EL -->
<dependency>
  <groupId>org.glassfish.web</groupId>
  <artifactId>el-impl</artifactId>
  <version>2.2</version>
</dependency>


<!-- http://repo1.maven.org/maven2/ -->
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>jstl</artifactId>
  <version>1.2</version>
</dependency>

  <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.1</version>
  </dependency>

  <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
  </dependency>


</dependencies>


 <build>
   <finalName>JavaServerFaces</finalName>

  <plugins>
     <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-compiler-plugin</artifactId>
       <version>2.3.1</version>
       <configuration>
           <source>1.6</source>
           <target>1.6</target>
       </configuration>
   </plugin>
</plugins>

Answer 1

我发现了同样的问题，今天刚刚解决。尽管我已经在pom.xml中声明了javax.servlet-api，但仍然存在问题。然后，我通过将javax.servlet-api:3.10.jar文件添加到项目的类路径中来修复它。

Answer 2

servlet-api.jar是服务器的一部分(在这里是Tomcat)。您需要在POM中声明对该jar的引用，并在“provided”范围中标记它，或者(如果出于某种原因您没有使用maven)您需要将它添加到您的类路径中(项目中web模块的库)。

重新安装高清后，您的Tomcat安装forder或maven存储库可能会有所不同。这似乎是一个环境问题。

Answer 3

正如上面有人提到的 - 这些库是应用程序服务器的一部分，因此它们不应该像 Spring 等其他库那样部署到服务器。您需要将它们作为提供的资源引用。

如果您的项目没有使用Maven（即教程等），您可以转到项目结构设置/Modules/模块/依赖项。。在依赖项列表下面是一个小加号（），您可以在其中选择“库”，然后将显示带有应用程序服务器库的弹出窗口。应按照随后提供的内容进行选择。