文档介绍:在用PL/SQLDeveloper连接数据库时出现“ORA-12541:TNS:无监听程序”错误。1、发现下面错误:TNSLSNRfor32-bitWindows:Version-Productionon20-9月-200810:25:26Copyright(c)1991,2005,:\oracle\product\\work\admin\写入D:\oracle\product\\work\log\写入D:\oracle\product\\work\trace\跟踪级别当前为0以pid=1704开始监听:(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1ipc)))监听该对象时出错:(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=)(PORT=1521)))TNS-12545:因目标主机或对象不存在,连接失败TNS-12560:TNS:协议适配器错误TNS-00515:因目标主机或对象不存在,连接失败  32-bitWindowsError:49:Unknownerror不再监听:(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1ipc)))2、查看Oracle的listener是否启动C:\DocumentsandSettings\mengzhaoliang>lsnrctlstatusLSNRCTLfor32-bitWindows:Version-Productionon20-9月-200810:50:44Copyright(c)1991,2005,(DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))TNS-12541:TNS:无监听程序TNS-12560:TNS:协议适配器错误TNS-00511:无监听程序  32-bitWindowsError:2:Nosuchfileordirectory正在连接到(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=)(PORT=1521)))TNS-12535:TNS:操作超时TNS-12560:TNS:协议适配器错误TNS-00505:操作超时  32-bitWindowsError:60:Unknownerror原来没有启动listener,用“lsnrctlstart”命令也不能启动。C:\DocumentsandSettings\mengzhaoliang>lsnrctlstartLSNRCTLfor32-bitWindows:Version-Productionon20-9月-200810:52:16Copyright(c)1991,2005,:请稍候...TNSLSNRfor32-bitWindows:Version-Production系统参数文件为D:\oracle\product\\work\admin\写入D:\oracle\pr