编译错误：包 javax.servlet 不存在

Question

I have a package in which I import javax.servlet.* and javax.servlet.http.* When I try to compile it in command prompt I get the error

package javax.servlet does not exist

I use JDK 1.7.0 and Tomcat 6.0.

Answer 1

You need to add the path to Tomcat's /lib/servlet-api.jar file to the compile time classpath.

javac -cp .;/path/to/Tomcat/lib/servlet-api.jar com/example/MyServletClass.java

The classpath is where Java needs to look for imported dependencies. It will otherwise default to the current folder which is included as . in the above example. The ; is the path separator for Windows; if you're using an Unix based OS, then you need to use : instead.

If you're still facing the same complation error, and you're actually using Tomcat 10 or newer, then you should be migrating the imports in your source code from javax.* to jakarta.* .

import jakarta.servlet.*;
import jakarta.servlet.http.*;

See also:

• jakarta.servlet.ServletException: Class [com.practice.MyServlet] is not a Servlet
• How do I import the javax.servlet / jakarta.servlet API in my Eclipse project?
• What exactly is Java EE?

Answer 2

If you are working with maven project, then add following dependency to your pom.xml

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.0.1</version>
    <scope>provided</scope>
</dependency>

Answer 3

Is it a JSP or Servlet?

Well, these two packages aren't actually built into Java like java.io is. Instead, they come with the Servlet-capable Web server (eg Tomcat). So before the Java compiler will be able to compile our Servlet, we need to let it know where to find the classes in these two packages.

The classes required are normally stored in a file called servlet.jar. The exact location of this file will depend on the particular Web server software you use, but in the case of Tomcat you can find it in the lib subdirectory of the main Tomcat installation directory (eg d:\\Program Files\\Apache Group\\jakarta-tomcat-3.2.3\\lib\\servlet.jar). For the Java compiler to be able to compile Servlets, you need to add this file to your Java class path. By default, Java looks for classes in the current directory (".") only. Thus, "." is the default class path. If you change the class path to include the servlet.jar file (".;d:...\\lib\\servlet.jar" under Windows, ".:/usr/.../lib/servlet.jar" in Unix), then the Servlet should compile just fine.

You can specify a class path to use when you run javac.exe as follows:

d:\\javadev> javac -classpath ".;d:\\Program Files\\Apache Group\\ jakarta-tomcat-3.2.3\\lib\\servlet.jar" MyServlet.java

Or in Linux javac uses : instead of ;

server1> javac -classpath ".:./servlet/servlet.jar" MyServlet.java

Answer 4

In a linux environment the soft link apparently does not work. you must use the physical path. for instance on my machine I have a softlink at /usr/share/tomacat7/lib/servlet-api.jar and using this as my classpath argument led to a failed compile with the same error. instead I had to use /usr/share/java/tomcat-servlet-api-3.0.jar which is the file that the soft link pointed to.

Answer 5

This is what solved the problem for me:

<dependency>
    <groupId>javax.servlet.jsp</groupId>
    <artifactId>jsp-api</artifactId>
    <version>2.2</version>
    <scope>provided</scope>
</dependency>

Answer 6

Copy the file " servlet-api.jar " from location YOUR_INSTILLATION_PATH\\tomcat\\lib\\servlet-api.jar and Paste the file into your Java Directory YOUR_INSTILLATION_PATH\\Java\\jdk1.8.0_121\\jre\\lib\\ext

this will work (tested).

Answer 7

JSP and Servlet are Server side Programming. As it comes as an built in package inside a Server like Tomcat. The path may be like wise

C:\Program Files\Apache Software Foundation\Tomcat 6.0\lib\jsp-api.jar
C:\Program Files\Apache Software Foundation\Tomcat 6.0\lib\servlet-api.jar

Just you want to Do is Add this in the following way

Right Click> My Computer>Advanced>Environment Variables>System variables

Do> New..> Variable name:CLASSPATH
           Variable value:CLASSPATH=.;C:\Program Files\Apache Software Foundation\Tomcat 6.0\lib\servlet-api.jar;

Answer 8

Add servlet-api.jar into your classpath. It will be available into Tomcat's lib folder.

Answer 9

This is what I found. Adding /usr/local/apache-tomcat-7.0.64/lib/servlet-api.jar in my environment variable as CLASSPATH on Mac.

if using bash: ~/.bash_profile $CLASSPATH=/usr/local/apache-tomcat-7.0.64/lib/servlet-api.jar

if using zsh: ~/.zshrc export CLASSPATH="usr/local/apache-tomcat-7.0.64/lib/servlet-api.jar"

Force it work right now, run source .bash_profile (or .zshrc) or one can restart computer and it works for the current user.

Answer 10

Even after trying suggested solution, it was not solving my problem because there where many instance of java path were entered by me.

1. I removed all java related path (different version java) from "Path, JAVA_HOME, JRE_HOME" and created from fresh.

2. i have set (path may changes as per different installation)
   a. JAVA_HOME as C:\\Program Files\\Java\\jdk1.8.0_191
   b.JRE_HOME as C:\\Program Files\\Java\\jdk1.8.0_191\\jre\\lib
   c. add binary file path in path: C:\\Program Files\\Java\\jdk1.8.0_191\\bin
   d. CLASSPATH as C:\\apache-tomcat-7.0.93\\lib

3. never try in the same command prompt if its already open while doing changes/creting system/user variables. close it and open new one.

Reference Image:

Answer 11

This happens because java does not provide with Servlet-api.jar to import directly, so you need to import it externally like from Tomcat , for this we need to provide the classpath of lib folder from which we will be importing the Servlet and it's related Classes.

For Windows you can apply this method:

1. open command prompt
2. type

 javac -classpath "C:\Program Files\Apache Software Foundation\Tomcat 9.0\lib\*;" YourFileName.java 
     

3. It will take all jar files which needed for importing Servlet, HttpServlet ,etc and compile your java file.

4. You can add multiple classpaths Eg.

javac -classpath "C:\Users\Project1\WEB-INF\lib\*; C:\Program Files\Apache Software Foundation\Tomcat 9.0\lib\*;" YourFileName.java

Answer 12

http://www.java2s.com/Code/JarDownload/javax.servlet/javax.servlet.jar.zip

Download zip file from the location and place it into following path after unziping files

%JAVA_HOME%/jre/lib/ext/

place files in the without any directory

Answer 13

The possible solution (Tested on ubuntu )

1. Open Terminal type geany .bashrc
2. Go to the top and paste this
   export CLASSPATH=$CLASSPATH:/web/apache-tomcat-8.5.39/lib/servlet-api.jar
3. Now save and close
4. Try running the program now.