Pl/SQL developer solves table garbled characters

Pl/SQL developer open the table garbled. In pl/SQL developer, view the table structure. The table structure comments are all ???, It is normal to view the table structure directly in the cmd window, which indicates that it is a problem with pl/SQL developer settings. An error is reported when you open developer. The reason is that the language set is not set on the client. Query the oracle server language Machine in cmd. select userenv ('language') from dual. The query result is SIMPLIFIED CHINESE_CHINA.ZHS16GBK. Add the window system environment variable NLS_LANG and set the value to SIMPLIFIED CHINESE_CHINA.ZHS16GBK. Do not discard SIMPLIFIED. Otherwise, an error is returned.