mysql - I want to display record getting value from database where id=id (insert value into database from getter method not work) in java -

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this question has answer here:

i create java file name attend.java

public class attend { string attend_id,studname,owner;  public string getowner() {     return owner; }  public void setowner(string owner) {     this.owner = owner;  }public string getstudname() {     return studname; }  public void setstudname(string studname) {     this.studname = studname; }  public string getattend_id() {     return attend_id; }  public void setattend_id(string attend_id) {     this.attend_id = attend_id; }} ;

other file dao file attenddao.java

, public class attenddao {public static list<attend> getallrecords(){     list<attend> list=new arraylist<attend>();         //attend u1=null;      try{         connection con=dbconnector.getconnection();         preparedstatement ps=con.preparestatement("select attend_id,studname,owner attend_detail owner=?");         attend u1 = null;         //system.out.println(u1.getowner());         ps.setstring(1,u1.getowner());         resultset rs=ps.executequery();         while(rs.next()){             attend u=new attend();             u.setattend_id(rs.getstring("attend_id"));             u.setstudname(rs.getstring("studname"));             u.setowner(rs.getstring("owner"));             list.add(u);         }     }catch(sqlexception e1){system.out.println("sql error:"+e1);     }catch(exception e){system.out.println(e);}     return list;     //} }},

i want owner value database if owner="xyz@xyz.com" display rows data

this database , value.. database name attend_detail.

attend_id  studname     owner  atn001     abcd       xyz@xyz.com atn002     efgh       null

this jsp view.jsp

<body> <%@page import="com.attend.detail.attenddao,com.attend.detail.attend,java.util.*"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>  <div class="container">  <h1>attendance list</h1>  <%  list<attend> list=attenddao.getallrecords();  request.setattribute("list",list);  %>   <div class="table-responsive" width="100%">  <table id="mytable" class="display table table-bordered" width="99%" >  <thead>         <tr>           <th>attend_id</th>           <th>student_id</th>            <th>owner</th>       </tr>       </thead>       <tbody>     <c:foreach items="${list}" var="u">         <tr>           <td>${u.getattend_id()}</td>           <td>${u.getstudentid()}</td>          <td>${u.getowner()}</td>         </tr>        </c:foreach>      </tbody>        </table>     </div></body>

it shows nullpointerexception how solve it.. please rply.

you need assign value after attend u1 = null, initialize null.

    attend u1 = null;      //system.out.println(u1.getowner());     ps.setstring(1,u1.getowner());

so, basically, u1 has null , need assign attend object correct issue.





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