java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

You need to add the "Maven Dependency" in the Deployment Assembly

• right click on your project and choose properties.
• click on Deployment Assembly.
• click add
• click on "Java Build Path Entries"
• select Maven Dependencies"
• click Finish.

Rebuild and deploy again

Note: This is also applicable for non maven project.

Two possible answers:

1- You did not include spring-beans and spring-context jars in your lib. If you are using maven (which will help a lot) those two lines will be enough

<dependency>
 <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
   <version>3.1.0.RELEASE</version>
</dependency>
<dependency>
 <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
   <version>3.1.0.RELEASE</version>
</dependency>

2- The necessary jars are in your classpath but are not deployed on tomcat.

I had the same problem with Idea Intellij and Spring 4. I fixed the problem and I wanted to share the answer with you.

I use tomcat 7 / idea intellij 13 / spring 4.

pom.xml dependencies:

  <properties>
    <spring.version>4.0.5.RELEASE</spring.version>
  </properties>

  <dependencies>     
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
enter code here
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.2</version>
    </dependency>
        <dependency>
      <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.4</version>
    </dependency>
  </dependencies>

In idea Intellij, you need to go to File -> Project Settings -> Artifacts.

Then

clean -> rebuild the project -> build the artifact, and everything will be ok.