Deployment is out of date due to changes in the underlying project contents. Deployment is out of date due to changes in the underlying project contents. You'll need to manually 'Redeploy' the projec

原因1:
导入的jar包路径不对,造成第一个错误,

原因2:
设置右键工程->属性->myeclipse->web->deployment
选use workbenk defaul setting 路径设置正确然后关eclipse,然后开eclipse就可以了