大家帮我看一下是什么错误!!

取得连接的时候的错误.
错误信息:
java.sql.SQLException: I/O例外です。: Connection refused(DESCRIPTION=(TMP=)(VSNNUM=168821248)(ERR=12519)(ERROR_STACK=(ERROR=(CODE=12519)(EMFI=4))))
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:333)
at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:404)
at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java:468)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:314)
at java.sql.DriverManager.getConnection(DriverManager.java:525)
at java.sql.DriverManager.getConnection(DriverManager.java:171)
at common.dbcon.ConnectionPool.makeNewConnection(ConnectionPool.java:296)
at common.dbcon.ConnectionPool.run(ConnectionPool.java:260)
at java.lang.Thread.run(Thread.java:595)