processquery.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 javax.servlet.http.*;
import java.io.*;
import javax.servlet.*;
import java.sql.*;
import jdbc.*;
import exception.*;

public class ProcessQuery extends HttpServlet
{
	public void doGet(HttpServletRequest req,HttpServletResponse resp) throws IOException
	{
		processRequest(req,resp);
	}
	
	public void doPost(HttpServletRequest req,HttpServletResponse resp) throws IOException
	{
		processRequest(req,resp);
	}
	
	public void processRequest(HttpServletRequest req,HttpServletResponse resp) throws IOException
	{
		String user=req.getParameter("user");
		//保存提交的用户名
		
		
		OutputStream os=resp.getOutputStream();
		DataOutputStream dos=new DataOutputStream(os);
		//获得向MIDlet返回信息的流
		
		int courseNum=-1;
		int[] courseSelected=null;
		String[] courseName=null;
		
		try
		{
			//courseNum=GetSelectedCourses(user,courseSelected,courseName);
			courseNum=getSelectedCourseNum(user);
			courseSelected=getSelectedCourseID(user);
			courseName=getSelectedCourseName(user);
			dos.writeInt(courseNum);
			for(int i=0;i<courseNum;i++)
			{
				dos.writeInt(courseSelected[i]);
				dos.writeUTF(courseName[i]);
			}
		}
		catch(SQLException e)//与数据库联接错误
		{
			dos.writeInt(-3);
			//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(user);
		
		int courseNum=-1;
		int[] courseSelected=null;
		String[] courseName=null;
		
		try
		{
			courseNum=getSelectedCourseNum(user);
			out.println("courseNum="+courseNum);
			courseSelected=getSelectedCourseID(user);
			courseName=getSelectedCourseName(user);
			//courseNum=GetSelectedCourses(user,courseSelected,courseName);
			//out.println(courseNum);
			//out.println(courseSelected[0]);	
			//out.println(courseName[0]);	
			for(int i=0;i<courseNum;i++)
			{
				out.println(courseSelected[i]);
				out.println(courseName[i]);
			}
		}
		catch(SQLException e)//与数据库联接错误
		{
			out.println("SQLException");
		}
		catch(DriverException e)
		{
			out.println("DriverException");
		}
		//catch(TestException e)
		//{
		//	out.println("TestException");
		//}
		finally
		{
			out.close();
		}
		*/
	}
	/*
	protected int GetSelectedCourses(String pUser,int[] courseSelected,String[] courseName) throws SQLException,DriverException
	//protected void GetSelectedCourses(String pUser,PrintWriter out) throws SQLException, IOException
	//测试用代码
	{
		//查询已选课程
		String user=pUser;
		//保存提交的用户名
		
		DatabaseConnection connection=new DatabaseConnection();
		//产生与数据库连接的类的实例，可能抛出SQLException
		connection.connect();
		int courseNum=0;
		//保存选择了的课程的数量
		courseNum=getSelectedCourseNum(user);		
		courseSelected=new int[courseNum];
		//保存选择了的课程的Id数组
		courseName=new String[courseNum];
		//保存选择的课程名称
		courseSelected=getSelectedCourseID(user);
		courseName=getSelectedCourseName(user);
		connection.close();
		return courseNum;
	}
	*/
	protected int getSelectedCourseNum(String pUser) throws SQLException,DriverException
	{
		String user=pUser;
		
		DatabaseConnection connection=new DatabaseConnection();
		connection.connect();
		return connection.getSelectedCourseNum(user);
	}
	
	protected int[] getSelectedCourseID(String pUser) throws SQLException,DriverException
	{
		String user=pUser;
		DatabaseConnection connection=new DatabaseConnection();
		connection.connect();
		return connection.getSelectedCourseID(user);
	}
	
	protected String[] getSelectedCourseName(String pUser) throws SQLException,DriverException
	{
		String user=pUser;
		DatabaseConnection connection=new DatabaseConnection();
		connection.connect();
		return connection.getSelectedCourseName(user);
	}
}