javax.servlet cannot be resolved

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：