jdk7使用0.1.18版本有问题

[zebe1989]

com.aliyun.openservices aliyun-log-logback-appender 0.1.18 com.aliyun.openservices aliyun-log-producer 0.3.8 jar-with-dependencies

因为项目中大量使用JDK7，在 0.1.18 版本时会出问题，错误信息如下：

at ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type com.aliyun.openservices.log.logback.LoghubAppender

Caused by: java.lang.UnsupportedClassVersionError: com/aliyun/openservices/log/logback/LoghubAppender : Unsupported major.minor version 52.0

10:03:07,112 |-ERROR in ch.qos.logback.core.joran.spi.Interpreter@30:88 - ActionException in Action for tag [appender] ch.qos.logback.core.joran.spi.ActionException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type com.aliyun.openservices.log.logback.LoghubAppender