updateclass.java

这是我自己做的一个选课系统

package org.chooseClass.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.chooseClass.database.DBConnect;
import org.hibernate.beans.Student;
import org.hibernate.beans.Chooseclass;
import org.hibernate.beans.Classes;
import org.hibernate.dao.ChooseclassDAO;
import org.hibernate.dao.ClassDAO;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.struts2.util.Constants;

public class UpdateClass extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * Constructor of the object.
	 */
	public UpdateClass() {
		super();
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

          this.doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/xml");
		PrintWriter out = response.getWriter();
		String class_id = request.getParameter("class_id");
		
		
		String stu_id = (String)request.getSession().getAttribute(Constants.USERNAME_KEY);
		
		WebApplicationContext wac=WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
		
		try{
			ChooseclassDAO chooseclassDAO = (ChooseclassDAO)wac.getBean("chooseclassDAO");
			
			boolean isValid = false;
			
			isValid = chooseclassDAO.isValid(stu_id, class_id);
			
			if(isValid) {
				out.print("你已经选了该课程！");
				return;
			}
			
			String isFull = chooseclassDAO.isFull(class_id);
			if(isFull.equals("full")){
					out.print("这们已经选满，请继续选其它课程！");
					return;
			}else{
			    int num = new Integer(isFull)+1;
			    
			    Classes classes = new Classes();
			    
			    classes.setSelectNum(Integer.toString(num));
			    
			    ClassDAO classDAO = (ClassDAO)wac.getBean("classDAO");
			    
			    classDAO.updateClass(classes);
			    
			    Chooseclass chooseclass = new Chooseclass();
			    
			    classes.setClassId(class_id);
			    
			    chooseclass.setClasses(classes);
			    
			    Student student = new Student();
			    
			    student.setStuId(stu_id);
			    
			    chooseclass.setStudent(student);
			
			   
			    out.print("你已经成功选择了这门课");
			    
			    return ;
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	
	}

}