mysqlcoursedao.java

一个web service的实例

package com.ibm.ta.dao.mysql;

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 com.ibm.ta.dao.CourseDAO;
import com.ibm.ta.dao.DAOException;
import com.ibm.ta.dao.DAOParameterException;
import com.ibm.ta.dao.DAOUtil;
import com.ibm.ta.webservice.Course;

public class MySQLCourseDAO implements CourseDAO {
	private MySQLDAOFactory factory;

	public MySQLCourseDAO(MySQLDAOFactory factory) {
		this.factory = factory;
	}

	public Course[] selectCourses() throws DAOException {
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		List results = new ArrayList();

		try {
			con = factory.createConnection();

			ps = con
					.prepareStatement("SELECT course_id, course_name from course");
			rs = ps.executeQuery();
			while (rs.next()) {
				Course course = new Course(rs.getLong(1), rs.getString(2));
				results.add(course);
			}
		} catch (SQLException sqle) {
			throw new DAOException(sqle.getMessage(), sqle);
		} finally {
			DAOUtil.closeResources(rs, ps, null, con);
		}
		return (Course[]) results.toArray(new Course[results.size()]);
	}

	public void insertCourse(String name) throws DAOException,
			DAOParameterException {
		Connection con = null;
		PreparedStatement ps = null;

		// Check the parameter
		if (name == null || name.trim().length() == 0) {
			throw new DAOParameterException(
					"Parameter course name is invalid or null");
		}

		try {
			con = factory.createConnection();

			ps = con
					.prepareStatement("INSERT INTO course (course_name) VALUES (?)");
			ps.setString(1, name);

			ps.executeUpdate();
		} catch (SQLException sqle) {
			throw new DAOException(sqle.getMessage(), sqle);
		} finally {
			DAOUtil.closeResources(null, ps, null, con);
		}
	}
}