报错:BASE64Encoder cannot be resolved to a type

解决方法:
1.选中项目,右击选择Java Build Path,在Libraries中,选择JRE System Libraries,选择Access rules,点击Edit

2.点击Add添加rule,Resolution选择Accessible,Rule Pattern填**(如果**依旧不能解决,填sun/**即可)

报错:BASE64Encoder cannot be resolved to a type