知识点：jsp servlet，MySQL数据库的基本操作，前端easyui框架。

适合人群：Java初学者、在校学生，（已经学过Java基础语法，对html有简单的了解，熟悉js、jquery语法）。

用到的工具：eclipse、MySQL

看下系统的截图：

package com.ischoolbar.programmer.servlet;

import java.io.IOException;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

import com.ischoolbar.programmer.dao.AttendanceDao;

import com.ischoolbar.programmer.dao.CourseDao;

import com.ischoolbar.programmer.dao.SelectedCourseDao;

import com.ischoolbar.programmer.model.Attendance;

import com.ischoolbar.programmer.model.Course;

import com.ischoolbar.programmer.model.Page;

import com.ischoolbar.programmer.model.SelectedCourse;

import com.ischoolbar.programmer.model.Student;

import com.ischoolbar.programmer.util.DateFormatUtil;

public class AttendanceServlet extends HttpServlet{

/**

*

*/

private static final long serialVersionUID = 1L;

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

doPost(request, response);

}

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

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

if("toAttendanceServletListView".equals(method)){

try {

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

} catch (ServletException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}else if("AddAttendance".equals(method)){

AddAttendance(request,response);

}else if("AttendanceList".equals(method)){

attendanceList(request,response);

}else if("DeleteAttendance".equals(method)){

deleteAttendance(request,response);

}else if("getStudentSelectedCourseList".equals(method)){

getStudentSelectedCourseList(request, response);

}

}

private void deleteAttendance(HttpServletRequest request,

HttpServletResponse response) throws IOException {

// TODO Auto-generated method stub

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

AttendanceDao attendanceDao = new AttendanceDao();

String msg = "success";

if(!attendanceDao.deleteAttendance(id)){

msg = "error";

}

attendanceDao.closeCon();

response.getWriter().write(msg);

}

private void attendanceList(HttpServletRequest request,

HttpServletResponse response) {

// TODO Auto-generated method stub

int studentId = request.getParameter("studentid") == null ? 0 : Integer.parseInt(request.getParameter("studentid").toString());

int courseId = request.getParameter("courseid") == null ? 0 : Integer.parseInt(request.getParameter("courseid").toString());

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

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

Integer currentPage = request.getParameter("page") == null ? 1 : Integer.parseInt(request.getParameter("page"));

Integer pageSize = request.getParameter("rows") == null ? 999 : Integer.parseInt(request.getParameter("rows"));

Attendance attendance = new Attendance();

//获取当前登录用户类型

int userType = Integer.parseInt(request.getSession().getAttribute("userType").toString());

if(userType == 2){

//如果是学生，只能查看自己的信息

Student currentUser = (Student)request.getSession().getAttribute("user");

studentId = currentUser.getId();

}

attendance.setCourseId(courseId);

attendance.setStudentId(studentId);

attendance.setDate(date);

attendance.setType(type);

AttendanceDao attendanceDao = new AttendanceDao();

List<Attendance> attendanceList = attendanceDao.getSelectedCourseList(attendance, new Page(currentPage, pageSize));

int total = attendanceDao.getAttendanceListTotal(attendance);

attendanceDao.closeCon();

response.setCharacterEncoding("UTF-8");

Map<String, Object> ret = new HashMap<String, Object>();

ret.put("total", total);

ret.put("rows", attendanceList);

try {

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

if("combox".equals(from)){

response.getWriter().write(JSONArray.fromObject(attendanceList).toString());

}else{

response.getWriter().write(JSONObject.fromObject(ret).toString());

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

private void AddAttendance(HttpServletRequest request,

HttpServletResponse response) {

// TODO Auto-generated method stub

int studentId = request.getParameter("studentid") == null ? 0 : Integer.parseInt(request.getParameter("studentid").toString());

int courseId = request.getParameter("courseid") == null ? 0 : Integer.parseInt(request.getParameter("courseid").toString());

String type = request.getParameter("type").toString();

AttendanceDao attendanceDao = new AttendanceDao();

Attendance attendance = new Attendance();

attendance.setCourseId(courseId);

attendance.setStudentId(studentId);

attendance.setType(type);

attendance.setDate(DateFormatUtil.getFormatDate(new Date(), "yyyy-MM-dd"));

String msg = "success";

response.setCharacterEncoding("UTF-8");

if(attendanceDao.isAttendanced(studentId, courseId, type,DateFormatUtil.getFormatDate(new Date(), "yyyy-MM-dd"))){

msg = "已签到，请勿重复签到！";

}else if(!attendanceDao.addAttendance(attendance)){

msg = "系统内部出错。请联系管理员！";

}

try {

response.getWriter().write(msg);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

private void getStudentSelectedCourseList(HttpServletRequest request,

HttpServletResponse response) {

// TODO Auto-generated method stub

int studentId = request.getParameter("student_id") == null ? 0 : Integer.parseInt(request.getParameter("student_id").toString());

SelectedCourse selectedCourse = new SelectedCourse();

selectedCourse.setStudentId(studentId);

SelectedCourseDao selectedCourseDao = new SelectedCourseDao();

List<SelectedCourse> selectedCourseList = selectedCourseDao.getSelectedCourseList(selectedCourse, new Page(1, 999));

selectedCourseDao.closeCon();

String courseId = "";

for(SelectedCourse sc : selectedCourseList){

courseId += sc.getCourseId()+ ",";

}

courseId = courseId.substring(0,courseId.length()-1);

CourseDao courseDao = new CourseDao();

List<Course> courseList = courseDao.getCourse(courseId);

courseDao.closeCon();

response.setCharacterEncoding("UTF-8");

try {

response.getWriter().write(JSONArray.fromObject(courseList).toString());

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

点击更多，获取系统文件。