<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <encoding>UTF-8</encoding>
                <compilerArguments>
                   <extdirs>src\main\webapp\WEB-INF\lib</extdirs>
                </compilerArguments>
            </configuration>
        </plugin>
        无关配置省略...
    </plugins>
</build>