javax.servlet cannot be resolved:
IDEA:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>provided</scope>
</dependency>
Eclipse:
菜单Window-Preferences:
web工程右键Properties:
项目右键Build Path-Configure Build Path: