尝试解决:

1. 监听服务和database instance没有起起来。

开启方法：开始—程序—管理工具—服务，打开服务面板,启动如下图2个服务

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2.Oracle本地的配置文件可能被自己不小心改了，检查一下（如果检查服务开了，还是不行）

我的目录：D:\app\renco\product\11.2.0\dbhome_1\NETWORK\ADMIN，一般后面几层目录名都一样的

请添加图片描述

listener.ora内容

# listener.ora Network Configuration File: D:\app\renco\product\11.2.0\dbhome_1\network\admin\listener.ora
# Generated by Oracle configuration tools.SID_LIST_LISTENER =(SID_LIST =(SID_DESC =(SID_NAME = CLRExtProc)(ORACLE_HOME = D:\app\renco\product\11.2.0\dbhome_1)(PROGRAM = extproc)(ENVS = "EXTPROC_DLLS=ONLY:D:\app\renco\product\11.2.0\dbhome_1\bin\oraclr11.dll")))LISTENER =(DESCRIPTION_LIST =(DESCRIPTION =(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))))ADR_BASE_LISTENER = D:\app\renco

sqlnet.ora内容

# sqlnet.ora Network Configuration File: D:\app\renco\product\11.2.0\dbhome_1\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.# This file is actually generated by netca. But if customers choose to 
# install "Software Only", this file wont exist and without the native 
# authentication, they will not be able to connect to the database on NT.SQLNET.AUTHENTICATION_SERVICES= (NTS)NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

tnsnames.ora内容（重要！！！！）

# tnsnames.ora Network Configuration File: D:\app\zhouml17060\product\11.2.0\client_1\NETWORK\ADMIN\tnsnames.ora
# Generated by Oracle configuration tools.LISTENER_ORCL =(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))ORACLR_CONNECTION_DATA =(DESCRIPTION =(ADDRESS_LIST =(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521)))(CONNECT_DATA =(SID = CLRExtProc)(PRESENTATION = RO)))ORCL =(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = orcl)))

我之前就是连公司数据库，使用其他人的tnsnames.ora文件把我自己的替换了，导致本地的配置没了。

增加了本地配置后，就连接成功了。