게시판 만들기 관련 데이터베이스 오류 발생

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게시판 실습 하려하는 초보입니다.유튜브 동영상을 보면서 따라가던 도중에게시판의 로그인을 하는 과정에서 '데이터베이스 오류가 발생했습니다.' 가 작동하며 로그인이 안되는 오류가 발생해서 조언좀 듣고자 글 써봅니다. 지혜좀 주십시오 ㅠ#수정 : 저의 mysql 버전은 5.7입니다.---------------------------------------------------------------------------------------------------------------------------------저의 코드 내용 및 콘솔 표시입니다.-코드-package user; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.PreparedStatement; public class UserDAO { private Connection conn; private PreparedStatement pstmt; private ResultSet rs; public UserDAO() { try { String dbURL &#61; &#34;jdbc:mysql://localhost:3306/BBS?serverTimezone&#61;UTC&#34;; String dbID &#61; &#34;root&#34;; String dbPassword &#61; &#34;root&#34;; Class.forName(&#34;com.mysql.cj.jdbc.Driver&#34;); conn &#61; DriverManager.getConnection(dbURL, dbID, dbPassword); } catch (Exception e) { e.printStackTrace(); } } public int login(String userID, String userPassword) { String SQL &#61; &#34;SELECT userPassword FROM USER WHERE userID &#61; ?&#34;; try { pstmt &#61; conn.prepareStatement(SQL); pstmt.setString(1, userID); rs &#61; pstmt.executeQuery(); if (rs.next()) { if(rs.getString(1).equals(userPassword)) { return 1; // 로그인 성공 } else return 0; //비밀번호 불일치 } return -1; // 아이디가 없음 } catch (Exception e) { e.printStackTrace(); } return -2; //데이터베이스 오류 } } -콘솔-java.lang.ClassNotFoundException: com.mysql.cj.jdbc.Driver at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1358) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1180) at java.base/java.lang.Class.forName0(Native Method) at java.base/java.lang.Class.forName(Class.java:333) at user.UserDAO.<init>(UserDAO.java:20) at org.apache.jsp.loginAction_jsp._jspService(loginAction_jsp.java:141) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:609) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:810) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1623) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:830) java.lang.NullPointerException at user.UserDAO.login(UserDAO.java:30) at org.apache.jsp.loginAction_jsp._jspService(loginAction_jsp.java:142) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:609) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:810) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1623) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:830) ---------------------------------------------------------------------------------------------------------------------------------- # 우선 오류 나서 해당 오류에 대한 피드백들이 몇가지 있어서 따라하긴 했지만, 똑같은 오류가 작동합니다. 1. dbURL 주소를 바꿔야한다. &#61; String dbURL &#61; &#34;jdbc:mysql://localhost:3306/BBS?serverTimezone&#61;UTC&#34;; 2. class.forName을 이렇게 바꿔야한다. &#61; Class.forName(&#34;com.mysql.cj.jdbc.Driver&#34;); 3. mysql-connector 파일을 최신버전이아닌 해당 버전으로 해야한다. &#61; mysql-connector-java-5.1.48-bin.jar

게시판 만들기 관련 데이터베이스 오류 발생

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