课堂签到APP

package database; import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import java.util.ArrayList; import utils.ClassTool; import utils.PassTool; import model.AnClass; /** 用户相关操作，数据库处理 */ public class DbUser { private Connection con = null; public DbUser() { con = DbMain.getInatance().getConnect(); } /** 学生登录（str/1-succ,-1用户名密码不对,-2登录失败，服务器错误） */ public String stuLogin(String name, String pass, boolean need_class) { String raw_pass = pass; pass = PassTool.getMD5(pass); Statement stmt = null; ResultSet res = null; String sql = ""; String result = ""; try { stmt = con.createStatement(); sql = "select pass from user_s where name='" + name + "'"; res = stmt.executeQuery(sql); /* 这里做代码简化，为方便理解，部分资源不进行释放 */ if (!res.next()) {// 用户不存在，注册用户并返回 int state = stuRegister(stmt, name, raw_pass);// 这里必须使用原生密码 if (state < 0) return state + ""; } else { if (!pass.equals(res.getString("pass"))) // 密码不对 return "-1"; if (!need_class) // 不需要返回课程表 return "1"; } // 检索课表并返回 sql = "select real_name from user_s where name='" + name + "'"; res = stmt.executeQuery(sql); if (res.next()) {// 查到课表，则返回课程表 String real = res.getString("real_name"); sql = "select class,time,place,teacher from info_c where student='" + name + "'"; res = stmt.executeQuery(sql); ArrayList<AnClass> list = new ArrayList<AnClass>(); while (res.next()) { String cls_name = res.getString("class"); int time = res.getInt("time"); String place = res.getString("place"); String teacher = res.getString("teacher"); if (teacher == null) teacher = "";// 此列可能为空 AnClass cls = new AnClass("", cls_name, place, time, teacher); list.add(cls); } result = "{\"name\":\"" + real + "\",\"table\":" + ClassTool.getClassJson(list) + "}"; } stmt.close(); res.close(); } catch (Exception ex) { System.out.println("登录异常"); result = "-2"; } return result; } /** 教师登录（str/1-succ,-1用户名密码不对,-2登录失败，服务器错误） */ public String teaLogin(String name, String pass, boolean need_class) { pass = PassTool.getMD5(pass); Statement stmt = null; ResultSet res = null; String sql = ""; String result = ""; try { stmt = con.createStatement(); sql = "select * from user_t where name='" + name + "' and pass='" + pass + "'"; res = stmt.executeQuery(sql); if (res.next()) { // 登录成功 if (need_class) {// 返回课程表 String real = res.getString("real_name"); sql = "select class,time,place from info_c where teacher='" + real + "'"; res = stmt.executeQuery(sql); ArrayList<AnClass> list = new ArrayList<AnClass>(); while (res.next()) { String cls_name = res.getString("class"); int time = res.getInt("time"); String place = res.getString("place"); AnClass cls = new AnClass("", cls_name, place, time, ""); list.add(cls); } result = "{\"name\":\"" + real + "\",\"table\":" + ClassTool.getClassJson(list) + "}"; } else { result = "1"; } } else { result = "-1"; } stmt.close(); res.close(); } catch (Exception ex) { System.out.println("登录异常"); result = "-2"; } return result; } /** 教师注册（str/1-succ,-1已经注册,-2注册失败，服务器错误，-3匹配失败） */ public String teaRegister(String name, String pass, String real) { pass = PassTool.getMD5(pass); Statement stmt = null; ResultSet res = null; String sql = ""; try {// 是否账号重复 stmt = con.createStatement(); sql = "select * from user_t where name='" + name + "' or real_name='" + real + "'"; res = stmt.executeQuery(sql); if (res.next()) { stmt.close(); res.close(); return "-1"; } } catch (Exception ex) {// 都报错了，就不必close了 return "-2"; } try {// 注册 sql = "insert into user_t values('" + name + "','" + pass + "','" + real + "')"; int num = stmt.executeUpdate(sql); stmt.close(); res.close(); if (num != 0) // 修改成功 return "1"; return "-2"; } catch (Exception e) { System.out.println("注册异常"); return "-2"; } } /** * 学生注册，1成功，-1失败。 */ private int stuRegister(Statement stmt, String name, String pass) { try { // 模拟登陆，获取课表 ArrayList<AnClass> list = ClassTool.getClassTable(name, pass); String real = ClassTool.getRealName(); if (list == null || list.size() == 0)// 登录失败 return -1; // 写入注册信息到数据库 String sql = "insert into user_s values('" + name + "','" + PassTool.getMD5(pass) + "','" + real + "')"; stmt.executeUpdate(sql); // 写入课程信息到数据库 for (int i = 0; i < list.size(); i++) { AnClass cls = list.get(i); sql = "insert into info_c values('" + name + "','','" + cls.getName() + "','" + cls.getTime() + "','" + cls.getPlace() + "','" + cls.getId() + "')"; stmt.executeUpdate(sql); } // 补充教师信息到课程信息中/*我真是太机智了*/ sql = "update info_c set teacher=" + "(select teacher from final_class " + "where class_id=id)where student=" + name; stmt.executeUpdate(sql); return 1; } catch (Exception e) { return -2; } } }