studentservlet.java

学生成绩管理系统JPA做的

package com.fengmanfei.student.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.fengmanfei.student.entity.ClassEO;
import com.fengmanfei.student.entity.CourseEO;
import com.fengmanfei.student.entity.StudentEO;
import com.fengmanfei.student.util.Pagination;

public class StudentServlet extends HttpServlet {

	private static final long serialVersionUID = -5398247075729048377L;

	private EntityManagerFactory emf;

	@Override
	public void init() throws ServletException {
		emf = Persistence.createEntityManagerFactory("student");
	}

	@SuppressWarnings("unchecked")
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		String action = request.getParameter("action");

		EntityManager em = emf.createEntityManager();

		try {
			if ("list".equals(action)) {
				// 每页显示 5 条记录
				final int pageSize = 5;
				// 当前页数
				int pageNum = 1;

				try {
					// 获取当前页数。如果没有输入或者格式错误，默认为 1
					pageNum = Integer.parseInt(request.getParameter("pageNum"));
				} catch (Exception e) {}

				// 获取记录总数
				int recordCount = ((Long) em.createQuery(
						" select count(*) from StudentEO ").getSingleResult())
						.intValue();

				// 计算总页数
				int pageCount = (recordCount + pageSize - 1) / pageSize;

				// 查询当前页内的记录
				List<StudentEO> studentList = em.createQuery(
						" from StudentEO order by id asc ").setFirstResult(
						(pageNum - 1) * pageSize).setMaxResults(pageSize)
						.getResultList();

				// 第一页 上一页 下一页 最后一页 等导航信息
				String pagination = Pagination.getPagination(pageNum,
						pageCount, recordCount, request.getContextPath()
								+ "/servlet/StudentServlet?action=list");

				request.setAttribute("pagination", pagination);
				request.setAttribute("studentList", studentList);

				request.getRequestDispatcher("/listStudent.jsp").forward(
						request, response);

			} else if ("initAdd".equals(action)) {

				List<ClassEO> classList = em.createQuery(" from ClassEO ")
						.getResultList();

				List<CourseEO> courseList = em.createQuery(" from CourseEO ")
						.getResultList();

				request.setAttribute("classList", classList);
				request.setAttribute("courseList", courseList);

				request.getRequestDispatcher("/addStudent.jsp").forward(
						request, response);

			} else if ("add".equals(action)) {

				EntityTransaction trans = em.getTransaction();

				trans.begin();

				String name = request.getParameter("name");
				String sex = request.getParameter("sex");
				String age = request.getParameter("age");
				String birthday = request.getParameter("birthday");
				String temporary = request.getParameter("temporary");

				StudentEO studentEO = new StudentEO();

				studentEO.setAge(Integer.parseInt(age));

				Date date = null;

				try {
					date = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);
				} catch (Exception e) {
				}

				studentEO.setBirthday(date);
				studentEO.setCreateDate(new Date());
				studentEO.setName(name);
				studentEO.setSex(sex);
				studentEO.setTemporary("true".equals(temporary));

				/**
				 * 设置 班级
				 */
				int classId = Integer.parseInt(request.getParameter("classId"));
				ClassEO classEO = em.find(ClassEO.class, classId);
				studentEO.setClassEO(classEO);

				/**
				 * 设置 选修课
				 */
				String[] courseId = request.getParameterValues("courseId");
				for (int i = 0; courseId != null && i < courseId.length; i++) {
					CourseEO courseEO = em.find(CourseEO.class, Integer
							.parseInt(courseId[i]));
					studentEO.getCourses().add(courseEO);
				}

				em.persist(studentEO);

				trans.commit();

				request.setAttribute("msg", "学生 " + studentEO.getName()
						+ " 添加成功。");

				request.setAttribute("studentEO", studentEO);
				request.getRequestDispatcher("/addStudentSuccess.jsp").forward(
						request, response);

			} else if ("edit".equals(action)) {

				List<ClassEO> classList = em.createQuery(" from ClassEO ")
						.getResultList();

				List<CourseEO> courseList = em.createQuery(" from CourseEO ")
						.getResultList();

				int studentId = Integer.parseInt(request
						.getParameter("studentId"));

				StudentEO studentEO = em.find(StudentEO.class, studentId);

				request.setAttribute("classList", classList);
				request.setAttribute("courseList", courseList);

				request.setAttribute("studentEO", studentEO);

				request.getRequestDispatcher("/addStudent.jsp").forward(
						request, response);

			} else if ("save".equals(action)) {

				EntityTransaction trans = em.getTransaction();

				trans.begin();

				int studentId = Integer.parseInt(request
						.getParameter("studentId"));

				String name = request.getParameter("name");
				String sex = request.getParameter("sex");
				String age = request.getParameter("age");
				String birthday = request.getParameter("birthday");
				String temporary = request.getParameter("temporary");

				StudentEO studentEO = em.find(StudentEO.class, studentId);

				Date date = null;

				try {
					date = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);
				} catch (Exception e) {
				}

				studentEO.setAge(Integer.parseInt(age));
				studentEO.setBirthday(date);
				// studentEO.setCreateDate(new Date());
				studentEO.setName(name);
				studentEO.setSex(sex);
				studentEO.setTemporary("true".equals(temporary));

				/**
				 * 设置 班级
				 */
				int classId = Integer.parseInt(request.getParameter("classId"));
				ClassEO classEO = em.find(ClassEO.class, classId);
				studentEO.setClassEO(classEO);

				/**
				 * 设置 选修课
				 */
				studentEO.getCourses().clear();
				String[] courseId = request.getParameterValues("courseId");
				for (int i = 0; courseId != null && i < courseId.length; i++) {
					CourseEO courseEO = em.find(CourseEO.class, Integer
							.parseInt(courseId[i]));
					studentEO.getCourses().add(courseEO);
				}

				em.persist(studentEO);

				trans.commit();

				request.setAttribute("msg", "学生 " + studentEO.getName()
						+ " 修改成功。");

				request.setAttribute("studentEO", studentEO);
				request.getRequestDispatcher("/addStudentSuccess.jsp").forward(
						request, response);

			} else if ("delete".equals(action)) {

				EntityTransaction trans = em.getTransaction();

				trans.begin();

				int studentId = Integer.parseInt(request
						.getParameter("studentId"));

				StudentEO studentEO = em.find(StudentEO.class, studentId);

				em.remove(studentEO);

				trans.commit();

				request.setAttribute("msg", "学生 " + studentEO.getName()
						+ " 删除成功。");

				request.setAttribute("studentEO", studentEO);
				request.getRequestDispatcher("/addStudentSuccess.jsp").forward(
						request, response);

			}

		} finally {
			em.close();
		}

	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doGet(request, response);
	}

	@Override
	public void destroy() {
		emf.close();
	}

}