问题:
Your lDE is missing natures to properly support your projects.Some extensions on the Eclipse Marketplace can be installed to support those natures
com.genuitec.eclipse.ast.deploy.core.deploymentnature
com.genuitec.eclipse.j2eedt.core.webnature
解决:
https://www.cnblogs.com/interdrp/p/18127992
参考:https://blog.csdn.net/Eileennnnnn/article/details/132881357
解决:因为Eclipse2019默认支持的是Java 1.8。通过重新配置JDK环境变量为1.8即可。
参考:https://blog.csdn.net/WYZSC/article/details/6176036
解决:保证WEB-INF/lib跟tomcat的common/lib下的JAR包没有重复的包即可!
将项目的web-inf/lib下的servlet-api.jar删掉!ok
参考:https://blog.csdn.net/ChlatZed/article/details/78858100
https://jingyan.baidu.com/article/3a2f7c2e32d60e67afd611bf.html
eclipse 2020版本竟然没有tomcat server!!!选项
https://blog.csdn.net/mimosa2008/article/details/123476790
https://mp.csdn.net/mp_blog/creation/editor/81136652