Recently because of the need to write a project interface, need to connect the remote Oracle database, at the beginning because I only locally installed MySQL, so use is connected to a local MySQL, it has tested the general interface in tomcat, can run, but then change the database, so want to install a local Oracle test, the installation is an afternoon with a night, so that the tragic history of share.Install the Oracle students believe the unloading Oracle (this sentence sounds bad, but the real operation of the people will not feel strange), basically every time you install Oracle will appear this or that problem, free to uninstall Oracle has become very important, because the uninstall is not clean will lead to the next installation o不成功,别胡说,直接走台阶。