ERROR String length must be a multiple of four.

java.lang.IllegalArgumentException: String length must be a multiple of four.
at com.alibaba.druid.util.Base64.base64ToByteArray(Base64.java:128) ~[druid-0.2.8.jar:0.2.8]
at com.alibaba.druid.util.Base64.base64ToByteArray(Base64.java:110) ~[druid-0.2.8.jar:0.2.8]
at com.alibaba.druid.filter.config.ConfigTools.decrypt(ConfigTools.java:126) ~[druid-0.2.8.jar:0.2.8]
at com.alibaba.druid.filter.config.ConfigTools.decrypt(ConfigTools.java:54) ~[druid-0.2.8.jar:0.2.8]
at com.alibaba.druid.filter.config.ConfigTools.decrypt(ConfigTools.java:48) ~[druid-0.2.8.jar:0.2.8]
at com.custom.common.jdbc.util.JdbcPasswordCallback.getPassword(JdbcPasswordCallback.java:19) ~[custom-commons-persistent.jar:na]
at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1273) [druid-0.2.8.jar:0.2.8]
at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:1207) [druid-0.2.8.jar:0.2.8]

很可能是字符集的问题造成的，试着改写你文件属性的字符集，或者通过request，response设置你的字符集试下，怎样出现的这个错误可不可以具体描述下呢

大概是Druid对数据库配置的密码进行解密时候的报错。可以参考https://blog.csdn.net/zengmingen/article/details/78832655