ArrayList求助
求大神帮助小弟下，
开始定义了DaoVote类
package dao;
import java.sql.*;
import java.util.*;
import vo.Vote;
public class VoteDao {
private Connection conn=null;
public void initConnection() throws Exception{
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/school","root","mysqladmin");
}
public ArrayList<Vote> getAllVotes() throws Exception{
ArrayList<Vote> al=new ArrayList<Vote>();
initConnection();
String sql="select teacherno,teachername,vote from t_vote";
Statement stat=conn.createStatement();
ResultSet rs=stat.executeQuery(sql);
while(rs.next()){
Vote vote=new Vote();
vote.setTeacherno(rs.getString("teacherno"));
vote.setTeachername(rs.getString("teachername"));
vote.setVotenumber(rs.getInt("vote"));
al.add(vote);
}
conn.close();
return al;
}
public void updateVotes(String[] teacherno)throws Exception{
initConnection();
String sql="update t_vote set vote=vote+1 where teacherno=?";
PreparedStatement ps=conn.prepareStatement(sql);
for(int i=0;i<teacherno.length;i++){
ps.setString(1,teacherno[i]);
ps.executeUpdate();
}
conn.close();
}
}
在JSP中使用
VoteDao vdao=new VoteDao();
ArrayList<Vote> votes=vdao.getAllVotes();
for(int i=0;i<votes.size();i++){
Vote vote=(Vote)votes.get(i);
总是出现错误，
org.apache.jasper.JasperException: An exception occurred processing JSP page /display.jsp at line 51
48: // String teachername = rs.getString("teachername");
49: //int vote = rs.getInt("vote");
50: VoteDao vdao=new VoteDao();
51: ArrayList<Vote> votes=vdao.getAllVotes();
52: for(int i=0;i<votes.size();i++){
53: Vote vote=(Vote)votes.get(i);
54: ArrayList??
[解决办法]
这个是jsp最终编译后会变成servlet和html，这个51行的报错有可能是java servlet里面的51行。不代表jsp中的51行，请楼主贴下全的jsp代码。
org.apache.jasper.JasperException: An exception occurred processing JSP page /display.jsp at line 51
