examquestiondao.java

本系统是用NetBeans IDE 6.1所写

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package com.online.dao;

import com.online.pojo.Item;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;

public class ExamQuestionDAO {
    
    private static final String GET_EXAM_ITEMS = "SELECT * FROM EItem ";
    
    private DataSource datasource;
    
    public ExamQuestionDAO() {
        
        try {
            Context ctx = new InitialContext();
            datasource = (DataSource) ctx.lookup("jdbc/OnlineExamDB");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    

    public List getExamQuestion() {
        
        List examQuestion = new ArrayList();
        Connection con = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        
        try {
            con = datasource.getConnection();
            ps = con.prepareStatement(GET_EXAM_ITEMS);
            rs = ps.executeQuery();
            while(rs.next()) {
                Item item = new Item(
                        rs.getString("QID"),
                        rs.getString("QUESTION"),
                        rs.getString("OPTION_A"),
                        rs.getString("OPTION_B"),
                        rs.getString("OPTION_C"),
                        rs.getString("OPTION_D"),
                        rs.getString("S_ANSWER")
                        );
                examQuestion.add(item);
            }
        } catch (SQLException se) {
            se.printStackTrace();
        } finally {
            if(rs != null) {
                try { rs.close(); } catch (Exception e) { e.printStackTrace(); }
            }
            if(ps != null) {
                try { ps.close(); } catch (Exception e) { e.printStackTrace(); }
            }
            if(con != null) {
                try { con.close(); } catch (Exception e) { e.printStackTrace(); }
            }
        }
        return examQuestion;
    }
}