The project cannot be built until build path errors are resolved

错误信息:The PRoject cannot be built until build path errors are resolved 错误原因:曾经引入了一个不需要的jar包,然后删除了。关掉eclipse再次打开时,就报这个错误 解决方法:右键工程,选择build path->configure build path,弹出的窗口里面选择libraries选项卡,删除jar包,然后选择自己电脑上的jar包,右键build path->Add To build path,即可解决问题