choiceitemdbdao.java

纯JAVA代码的考试系统

package org.fangsoft.testcenter.dao.db;

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 org.fangsoft.testcenter.dao.ChoiceItemDao;
import org.fangsoft.testcenter.model.ChoiceItem;

public class ChoiceItemDBDao implements ChoiceItemDao {
	private static final ChoiceItemDBDao cdao=new ChoiceItemDBDao();
	public static final ChoiceItemDBDao getInstance(){
		return cdao;
	}
	private void close(Connection conn) {
		if (conn != null)
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
	}

	// implement findByQid
	private static final String sql_findByQid = "select * from CHOICE where Q_ID=?";

	public List<ChoiceItem> findByQid(int Q_id) {
		Connection conn = null;
		List<ChoiceItem> chList = new ArrayList<ChoiceItem>();
		try {
			conn = ConnectionFactory.getConnection();
			PreparedStatement ps = conn.prepareStatement(sql_findByQid);
			ps.setInt(1, Q_id);
			ResultSet rs = ps.executeQuery();
			while (rs.next()) {
				ChoiceItem ch = new ChoiceItem();
				ch.setId(rs.getInt("C_ID"));
				ch.setName(rs.getString("NAME"));
				ch.setCorrect(rs.getInt("CORRECT") > 0 ? true : false);
				chList.add(ch);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			this.close(conn);
		}
		return chList;
	}

	// implement insert
	private static final String sql_insert = "inert into CHOICE(C_ID,Q_ID,NAME,CORRECT) values(?,?,?,?)";

	public void insert(ChoiceItem choice) {
		Connection conn = null;
		try {
			conn = ConnectionFactory.getConnection();
			conn.setAutoCommit(false);
			PreparedStatement stmt = conn
					.prepareStatement("select SEQ_CHOICE.nextval from dual");
			ResultSet rs = stmt.executeQuery();
			int C_id = 0;
			if (rs.next())
				C_id = rs.getInt(1);
			PreparedStatement ps = conn.prepareStatement(sql_insert);
			ps.setInt(1, C_id);
			ps.setInt(2, choice.getId());
			ps.setString(3, choice.getName());
			ps.setInt(4, choice.isCorrect() == true ? 1 : 0);
			ps.executeUpdate();
			conn.commit();
		} catch (SQLException e) {
			e.printStackTrace();
			try {
				conn.rollback();
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		} finally {
			this.close(conn);
		}
	}

	// implement update
	private static final String sql_update = "update CHOICE set Q_ID=?,NAME=?,CORRECT=? where C_ID=?";

	public void update(ChoiceItem choice) {
		Connection conn = null;
		try {
			conn = ConnectionFactory.getConnection();
			PreparedStatement ps = conn.prepareStatement(sql_update);
			ps.setInt(1, choice.getId());
			ps.setString(2, choice.getName());
			ps.setInt(3, choice.isCorrect() == true ? 1 : 0);
			ps.setInt(4, choice.getId());
			ps.executeUpdate();
			choice.setId(0);
		} catch (SQLException e) {
			e.printStackTrace();
			try {
				conn.rollback();
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		} finally {
			this.close(conn);
		}
	}

	// implement delete
	private static final String sql_delete = "delete from CHOICE where Q_ID=?";

	public void delete(int Q_id) {
		Connection conn = null;
		try {
			conn = ConnectionFactory.getConnection();
			PreparedStatement ps = conn.prepareStatement(sql_delete);
			ps.setInt(1, Q_id);
			ps.executeUpdate();
		} catch (SQLException e) {
			e.printStackTrace();
			try {
				conn.rollback();
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		} finally {
			this.close(conn);
		}
	}
	public static void main(String[] args){
		List<ChoiceItem> item=new ArrayList<ChoiceItem>();
		ChoiceItemDBDao c=new ChoiceItemDBDao();
		item=c.findByQid(1);
		//c.deleteByTrID(2);
		for(int i=0;i<item.size();i++){
		System.out.println(item.get(i).getId()+","+item.get(i).getName());
		}
		
	}
}