processallcourse.java

这是一个可以在手机客户端运行的选课系统 这个是客户端

package course.select;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import jdbc.*;
import java.sql.*;
import exception.*;

/**
 * @version 	1.0
 * @author
 */
public class ProcessAllcourse extends HttpServlet implements Servlet {

	/**
	* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
	*/
	public void doGet(HttpServletRequest req, HttpServletResponse resp)
		throws ServletException, IOException {
			processRequest(req,resp);
	}

	/**
	* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
	*/
	public void doPost(HttpServletRequest req, HttpServletResponse resp)
		throws ServletException, IOException {
			processRequest(req,resp);
	}

	/**
	 * @param req
	 * @param resp
	 */
	private void processRequest(HttpServletRequest req, HttpServletResponse resp) throws IOException
		// TODO 自动生成方法存根
	{
		OutputStream os=resp.getOutputStream();
		DataOutputStream dos=new DataOutputStream(os);
		//获得向MIDlet返回所有信息的流
		
		try
		{
			DatabaseConnection connection=new DatabaseConnection();
			//产生与数据库连接的类的实例，可能抛出SQLException
			connection.connect();
			String [] allCourse=new String[connection.getTotalCourseNum()];
			int [] courseID=connection.getAllCourse(allCourse);
			//获得表示所用课程的字符串数组
			
			connection.close();
			dos.writeInt(allCourse.length);
			//返回所有课程数量
			for(int i=0;i<allCourse.length;i++)
			{
				dos.writeInt(courseID[i]);
				dos.writeUTF(allCourse[i]);
			}
			//返回课程信息	
		}
		catch(SQLException e)
		{
			dos.writeInt(-3);
			//-3代表连接数据库错误
//			返回提示信息
		}
		catch(DriverException e)
		{
			dos.writeInt(-3);
		}
		finally
		{
			dos.close();
		}
		
		//调试用代码
		/*
		PrintWriter out=resp.getWriter();
		out.println("ok");

		*/
	}

}