Several ports (8005, 8080, 8009) required by Tomcat v9.0 Server at localhost are already in use. The server may already be running in another process, or a system process may be using the port. To start this server you will need to stop the other process or change the port number(s).
端口被占用了！
解决方法就是要去把占用了端口的工程关掉：
开始->运行->cmd管理员运行->输入 netstat -ano，回车，UDP旁边的一列为IP，找到8080，然后找到对应最后一列的PID
打开任务管理器---服务---关闭相应的PID的进程，重启eclipse，run就行了