报错现象:

处理过程:
1、先是查看了Project Structure,发现设置的都是1.8
2、然后又查看了Settings->Build,Execution,Deployment->Compiler->Java Compiler,发现设置的也是8
3、修改pom文件,在project下添加如下配置,问题解决:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>
</build>