（二）登錄功能實現
1. 編寫前端頁面
若jsp頁面中文亂碼：在jsp中指定頁面顯示的編碼為GBK
添加page命令
<%@ page language="java" contentType="text/html; charset=GBK" %>
參考：https://www.cnblogs.com/beijiguangyong/archive/2012/03/31/2437124.html
*其他所有出現編碼的地方也要改掉
2. 編寫login.jsp，並設置為首頁
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login.jsp
<%@ page language="java" contentType="text/html; charset=GBK" %> <!DOCTYPE html> <html lang="en"> <head> <meta charset="GBK"> <title>用戶登錄</title> </head> <body> <form action="${pageContext.request.contextPath}/studentServlet" method="post"> <div class="errorInfo">${error}</div> <p>學號：<input type="text" size="20" name="stuNo"></p> <p>密碼：<input type="password" size="20" name="stuPwd"></p> <p><input type="submit" value="登錄"></p> </form> </body> </html> -
設置為首頁：
web.xml添加
<!-- 設置歡迎頁面 --> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list>
3. 編寫dao層用戶登陸的接口
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StudentDao
public interface StudentDao { //得到要登錄的研究生 public Student getLoginStudent(Connection conn,String stuNo) throws SQLException; }
4. 編寫dao接口的實現層
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StudentDaoImpl
package dao.student; import dao.BaseDao; import domain.Student; import org.junit.Test; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class StudentDaoImpl implements StudentDao { @Override public Student getLoginStudent(Connection conn, String stuNo) throws SQLException { PreparedStatement ps = null; ResultSet rs = null; Student stu = null; if (conn != null) { String sql = "select * from student where stu_no=?"; Object[] params = {stuNo}; rs = BaseDao.executeQuery(conn, sql, params, ps, rs); if (rs.next()) { stu = new Student(); stu.setStuNo(rs.getString(1)); stu.setPassword(rs.getString(2)); stu.setStuName(rs.getString(3)); stu.setSpecialty(rs.getString(4)); stu.setSex(rs.getBoolean(5)); stu.setBirth(rs.getDate(6)); stu.setPhone(rs.getString(7)); stu.setEmail(rs.getString(8)); stu.setGradSchoolCode(rs.getString(9)); stu.setGradSchoolName(rs.getString(10)); stu.setGradSpecCode(rs.getString(11)); stu.setGradSpecName(rs.getString(12)); } BaseDao.closeResource(null, ps, rs); } return stu; } }
5. 業務層接口
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StudentService
public interface StudentService { /** * 驗證是否登錄成功 * * @return 登錄成功則返回用戶對象，無則null */ public Student isLogin(String stuNo, String pwd) throws SQLException; }
6. 業務層實現類
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StudentServiceImpl
public class StudentServiceImpl implements StudentService { private StudentDao studentDao; public StudentServiceImpl() { studentDao = new StudentDaoImpl(); } /** * 驗證是否登錄成功 * * @return 有登錄成功則返回用戶對象，無則null */ @Override public Student isLogin(String stuNo, String pwd) { Connection conn = null; Student stu = null; try { conn = BaseDao.getConnection(); stu = studentDao.getLoginStudent(conn, stuNo); if (stu != null) { if (!pwd.equals(stu.getPassword())) stu = null; } } catch (SQLException e) { e.printStackTrace(); } finally { BaseDao.closeResource(conn, null, null); } return stu; } }
7. 編寫Servlet
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StudentServlet
記得添加@WebServlet注解
@WebServlet("/studentServlet") public class StudentServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //獲取客戶端提交的數據 String stuNo = req.getParameter("stuNo"); String stuPwd = req.getParameter("stuPwd"); try { StudentService studentService = new StudentServiceImpl(); Student stu = studentService.isLogin(stuNo, stuPwd); if (stu != null) { //有該用戶，存進session，跳轉到查看導師頁面 HttpSession session = req.getSession(); session.setAttribute(Constants.STUDENT_SESSION, stu); resp.sendRedirect("stu_check_tutor.jsp"); } else { //無該用戶，跳轉至登錄頁面，並提示錯誤信息 req.setAttribute("error", "用戶名或密碼不正確"); req.getRequestDispatcher("login.jsp").forward(req, resp); System.out.println("結束Servlet...."); } } catch (SQLException e) { e.printStackTrace(); } } }