一:ORA-12505
问题
Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: Listener refused the connection with the following error: ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
TNS：监听器当前不知道连接描述符中给出的SID
解决方法:
例如，正确的jdbc字符串应该是...... jdbc:oracle:thin:@myserver:1521/XE 但是我使用的jdbs字符串是...... jdbc:oracle:thin:@myserver:1521:XE （注意：之间1521和XE应该是/）