SpringBoot 发布到Tomcat运行报错原因之一
IntelliJ IDEA搭建SpringBoot应用: https://www.cnblogs.com/winner-0715/p/6666302.html
SpringBoot发布到独立的tomcat中运行: https://blog.****.net/qq_28988969/article/details/78135768
1、当版本号为：
1.5.6.RELEASE
可以以在Tomcat7中运行
2、当版本号为：
2.0.3.RELEASE
在Tomcat8中运行正常
在Tomcat7中会报异常：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'defaultValidator' defined in class path resource [org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.validation.beanvalidation.LocalValidatorFactoryBean]: Factory method 'defaultValidator' threw exception; nested exception is java.lang.NoClassDefFoundError: javax/el/ELManager
原因： tomcat7中的el-api，版本太低