use -source 5 or higher to enable annotations
pom.xml中加入：

<build>    <plugins>       <plugin>            <groupId>org.apache.maven.plugins</groupId>    <artifactId>maven-compiler-plugin</artifactId>    <version>2.0.2</version>    <configuration>    <source>1.6</source>    <target>1.6</target>    </configuration></plugin>    </plugins> </build>