processselect.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 ProcessSelect 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
	{
		//更新用户选课内容
		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
		
		InputStream is=req.getInputStream();
		DataInputStream dis=new DataInputStream(is);
		//获得MIDlet发送的信息的流
		
		int courseNum=dis.readInt();
		//保存用户选择的课程数目
		
		int courseSelected[]=new int[courseNum];
		//保存用户选择的课程的Id
		
		for(int i=0;i<courseNum;i++)
			courseSelected[i]=dis.readInt();
			
		try
		{
			UpdateSelectedCourses(user,courseNum,courseSelected);
			dos.writeInt(1);
			//返回提示信息
		}
		catch(DriverException e)
		{
			dos.writeInt(-3);
			//驱动错误属于数据库错误
		}
		catch(SQLException e)//访问数据库错误
		{
			dos.writeInt(-1);
			//返回提示信息
		}
		catch(QuotaException e)
		{
			dos.writeInt(-5);
			/*
			int [] courseID=e.getCourseID();
			int i=0;
			while(courseID[i]!=0)
				i++;
			dos.writeInt(i);
			for(;i>0;i--)
				dos.writeInt(courseID[i-1]);
			*/
			//返回已满人数课程
		}
		finally
		{
			dos.close();
		}
		
		
		//测试用代码
		/*
		int courseNum=2;
		int courseSelected[]=new int[courseNum];
		courseSelected[0]=1;
		courseSelected[1]=3;
		//courseSelected[2]=3;
		PrintWriter out=resp.getWriter();
		out.println(user);
		out.println("courseNum="+courseNum);
		out.println("course1="+courseSelected[0]);
		out.println("course2="+courseSelected[1]);
		//out.println("course3="+courseSelected[2]);
		try
		{
			UpdateSelectedCourses(user,courseNum,courseSelected);
			out.println("ok");
		}
		catch(DriverException e)
		{
			out.println(-3);
		}
		catch(SQLException e)//访问数据库错误
		{
			out.println("SQLException");
		}
		catch(QuotaException e)
		{
			int [] courseID=e.getCourseID();
			int i=0;
			while(courseID[i]!=0)
				i++;
			out.println(i);
			for(;i>0;i--)
				out.println(courseID[i-1]);
			//返回已满人数课程
		}
		finally
		{
			out.close();
		}
		*/
	}
	
	protected void UpdateSelectedCourses(String user,int courseNum,int[] courseSelected) throws SQLException,DriverException,QuotaException
	{	
		DatabaseConnection connection=new DatabaseConnection();
		//产生与数据库连接的类的实例，可能抛出SQLException
		connection.connect();
		connection.updateSelectedCourse(user,courseSelected,courseNum);
		//可能抛出SQLException
		connection.close();
	}
	
}