아이디 비밀번호 찾기하는데 자꾸 java.lang.NullPointerException 오류가 떠요,,

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아이디비밀번호찾기 find.jsp<%@ page language="java" contentType="text/html; charset=EUC-KR" pageEncoding="EUC-KR"%> 아이디비밀번호찾기

아이디찾기

비밀번호찾기

find_pro_id.jsp <%@ page language="java" contentType="text/html; charset=EUC-KR" pageEncoding="EUC-KR"%> <%@page import="com.user.MemberDAO" %> <%@page import="com.user.MemberUser" %> <% request.setCharacterEncoding("euc-kr"); MemberDAO dao = MemberDAO.getInstance(); String userid; userid = dao.Find_id(muser); String userirum = request.getParameter("userirum"); String usertel = request.getParameter("usertel"); String useremail = request.getParameter("useremail"); if(userid == null){ %> 아이디찾기 <% }else{ %> <%} %> find_pro_pwd.jsp <%@ page language="java" contentType="text/html; charset=EUC-KR" pageEncoding="EUC-KR"%> <%@page import="com.user.MemberDAO" %> <%@page import="com.user.MemberUser" %> <% request.setCharacterEncoding("euc-kr"); MemberDAO dao = MemberDAO.getInstance(); String pwd=null; pwd = dao.Find_pwd(muser); if(pwd ==null){ %> 아이디찾기 <% }else{ %> <%} %> MemberDAO.java package com.user; import java.sql.*; import javax.naming.*; import javax.sql.DataSource; public class MemberDAO { public static final int MEM_NONEXIST = 0; public static final int MEM_EXIST = 1; public static final int MEM_JOIN_SUCCESS = 1; public static final int MEM_JOIN_FAIL = 0; public static final int MEM_LOGIN_SUCCESS = 1; public static final int MEM_LOGIN_PW_NOT = 0; public static final int MEM_LOGIN_NOT = -1; private static MemberDAO dao; private DataSource ds; private Connection con; private Context cnt; private PreparedStatement pstmt; private ResultSet rs; public MemberDAO() { //생성자 , 싱글톤 패턴으로 하기 위해 생성자를 private로 설정 try { cnt = new InitialContext(); ds = (DataSource)cnt.lookup("java:comp/env/jdbc/mysql"); } catch (Exception e) { } } //싱글톤 public static MemberDAO getInstance() { if(dao == null ) dao = new MemberDAO(); return dao; } public int insertMember(MemberUser muser) { int n = 0; PreparedStatement pstmt = null; String sql = "insert into member" + "(userid, pwd, userirum, useremail, sample4_postcode ,sample4_roadAddress ,userAddress , usertel)" + "values(?,?,?,?,?,?,?,?)"; try { con = ds.getConnection(); System.out.println("con 연결:" + con); pstmt = con.prepareStatement(sql); pstmt.setString(1, muser.getUserid()); pstmt.setString(2, muser.getPwd()); pstmt.setString(3, muser.getUserirum()); pstmt.setString(4, muser.getUseremail()); pstmt.setString(5, muser.getSample4_postcode()); pstmt.setString(6, muser.getSample4_roadAddress()); pstmt.setString(7, muser.getUserAddress()); pstmt.setString(8, muser.getUsertel()); pstmt.executeUpdate(); n = MemberDAO.MEM_JOIN_SUCCESS; }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(pstmt !=null) pstmt.close(); if(con !=null) con.close(); }catch(Exception e){ e.printStackTrace(); } } return n; } //회원아이디로검색 public int checkid(String userid) { int n = 0; Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; String sql ="select userid from member where userid = ?"; try { con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1, userid); rs = pstmt.executeQuery(); if(rs.next()) { n = MemberDAO.MEM_EXIST; }else { n= MemberDAO.MEM_NONEXIST; } }catch(Exception e) { e.printStackTrace(); }finally { try { if(pstmt != null)pstmt.close(); if(con != null)con.close(); }catch(Exception e) { e.printStackTrace(); } } return n; } //로그인 public int memberCheck(String userid, String pwd){ int n = 0; String rPwd; Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; String sql = "select pwd from member where userid = ?"; try{ con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1, userid); rs=pstmt.executeQuery(); if(rs.next()){ rPwd = rs.getString("pwd"); if(rPwd.equals(pwd)){ n = MemberDAO.MEM_LOGIN_SUCCESS; // 로그인 성공 }else{ n = MemberDAO.MEM_LOGIN_PW_NOT; // 비밀번호가 틀림 } }else{ n = MemberDAO.MEM_LOGIN_NOT; //회원이 아님. } }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(rs !=null) rs.close(); if(pstmt !=null) pstmt.close(); if(con !=null)con.close(); }catch(Exception e){ e.printStackTrace(); } } return n; } public MemberUser getMember(String userid){ MemberUser muser = null; Connection con = null; PreparedStatement pstmt =null; ResultSet rs = null; String sql = "select * from member where userid = ?"; try{ con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1,userid); rs = pstmt.executeQuery(); if(rs.next()){ muser = new MemberUser(); muser.setUserid(rs.getString("userid")); muser.setPwd(rs.getString("pwd")); muser.setUserirum(rs.getString("irum")); muser.setUseremail(rs.getString("useremail")); muser.setSample4_postcode(rs.getString("sample4_postcode")); muser.setSample4_roadAddress(rs.getString("sample4_roadAddress")); muser.setUserAddress(rs.getString("userAddress")); muser.setUsertel(rs.getString("usertel")); } }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(rs !=null) rs.close(); if(pstmt !=null) pstmt.close(); if(con !=null)con.close(); }catch(Exception e){ e.printStackTrace(); } } return muser; } public int updateMember(MemberUser muser){ int n = 0; Connection con = null; PreparedStatement pstmt =null; String sql = "update member set userirum=?, useremail=?, userAddress=? where userid=?"; try{ con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1, muser.getUserirum()); pstmt.setString(2, muser.getUseremail()); pstmt.setString(3, muser.getUserAddress()); pstmt.setString(4, muser.getUserid()); n=pstmt.executeUpdate(); }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(pstmt !=null) pstmt.close(); if(con !=null)con.close(); }catch(Exception e){ e.printStackTrace(); } } return n; } //try catch 안에다가 에러나는 구문을 넣어주거나 //해당 메서드 명 옆에 throws exception을 붙힘 오류 떠서 예외처리해야됨 public String Find_id(MemberUser muser) throws Exception { String userid = null; String sql ="select userid from member where userirum=? and useremail=? and usertel=?"; try { con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1, muser.getUserirum()); pstmt.setString(1,muser. getUseremail()); pstmt.setString(1, muser.getUsertel()); System.out.println("이름" + muser.getUserid()); System.out.println("이메일" + muser.getUseremail()); System.out.println("전번" + muser.getUsertel());; rs=pstmt.executeQuery(); while(rs.next()) { userid = rs.getString(userid); System.out.println(userid); } }finally { con.close(); pstmt.close(); rs.close(); } return userid; } public String Find_pwd(MemberUser muser) throws Exception { String pwd =null; String sql ="select pwd from member where userirum=? and pwd=? and useremail=?"; try { con = ds.getConnection(); pstmt = con.prepareStatement(sql); pstmt.setString(1, muser.getUserirum()); pstmt.setString(2, muser.getUserid()); pstmt.setString(3, muser.getUseremail()); rs=pstmt.executeQuery(); while(rs.next()) { pwd = rs.getString(pwd); System.out.println(pwd); } }finally { con.close(); pstmt.close(); rs.close(); } return pwd; } } 아이디를 찾으면 오류가 뜹니다 HTTP Status 500 – Internal Server Error Type Exception Report Message An exception occurred processing [jsp/find_pro_id.jsp] at line [19] Description The server encountered an unexpected condition that prevented it from fulfilling the request. Exception org.apache.jasper.JasperException: An exception occurred processing [jsp/find_pro_id.jsp] at line [19] 16: MemberDAO dao = MemberDAO.getInstance(); 17: 18: String userid; 19: userid = dao.Find_id(muser); 20: 21: String userirum = request.getParameter("userirum"); 22: String usertel = request.getParameter("usertel"); Stacktrace: org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:607) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:481) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) Root Cause javax.servlet.ServletException: java.sql.SQLException: No value specified for parameter 2 org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:667) org.apache.jsp.jsp.find_005fpro_005fid_jsp._jspService(find_005fpro_005fid_jsp.java:189) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:458) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) Root Cause java.sql.SQLException: No value specified for parameter 2 com.mysql.jdbc.SQLError.createSQLException(SQLError.java:965) com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898) com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887) com.mysql.jdbc.SQLError.createSQLException(SQLError.java:861) com.mysql.jdbc.PreparedStatement.checkAllParametersSet(PreparedStatement.java:2211) com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:2191) com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:2121) com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1941) org.apache.tomcat.dbcp.dbcp2.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:122) org.apache.tomcat.dbcp.dbcp2.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:122) com.user.MemberDAO.Find_id(MemberDAO.java:240) org.apache.jsp.jsp.find_005fpro_005fid_jsp._jspService(find_005fpro_005fid_jsp.java:145) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:458) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) Note The full stack trace of the root cause is available in the server logs. Apache Tomcat/9.0.12 비밀번호를 찾으면 테이블에 있는 값을 똑같이 입력해도 찾질 못하네요

black_p · Answer

NPE는 NULL을 가진 객체를 사용하려고 했기 때문에 나오는 에러입니다.그렇기에 500페이지가 나오네요그중에 19번 DAO 쪽에서 에러가 났다고합니다.거기서 널값을 받는 부분이 생긴거같은데 로그 찍으면서 확인해보시거나 쿼리문쪽을 확인해보세요

아제발요살려주세요 · Answer

답변 너무 감사합니다 null 값을 받는부분을 null을 없앴는데도 불구하고 계속 userid &#61;dao.find_id(muser);쪽에 에러가 나네요,java.lang.NullPointerException이 쪽에서도 계속 오류가 나고 ㅜㅜ 쿼리에 null값이 있긴 한데 find에서 가져오는 값이 아닌 값인데도 관련이 있는건가요?코딩 배운지 얼마 안돼서 어디가 잘못된건지 잘 모르겠네요,,

black_p · Answer

애초에 npe에러가 난 시점은 널값을 사용하려 했기 때문에 나는 예외입니다.쿼리문에서 널값을 가지고와서 사용하다가 난 에러같네요보통 이때 반환값이 문자열이라면 데이터베이스에서 가지고온 객체를 null체크해서 빈 문자열을 넣어주는 방식으로 처리가 가능합니다. 혹은 npe 예외를 잡는 try catch를 이용해 에러메세지를 만들어서 반환해주던가요

귀신님 · Answer

Find_id 메서드에서Sql에 사용되는 파라미터 입력이 모두 1번째 파라미터로 설정되어있네요.

아이디 비밀번호 찾기하는데 자꾸 java.lang.NullPointerException 오류가 떠요,,

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