完成一个IDEA web项目（二）登录功能实现
（二）登录功能实现
1. 编写前端页面
若jsp页面中文乱码：在jsp中指定页面显示的编码为GBK
添加page命令
<%@ page language="java" contentType="text/html; charset=GBK" %>
参考：https://www.cnblogs.com/beijiguangyong/archive/2012/03/31/2437124.html
*其他所有出现编码的地方也要改掉
2. 编写login.jsp，并设置为首页
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login.jsp
<%@ page language="java" contentType="text/html; charset=GBK" %> <!DOCTYPE html> <html lang="en"> <head> <meta charset="GBK"> <title>用户登录</title> </head> <body> <form action="${pageContext.request.contextPath}/studentServlet" method="post"> <div class="errorInfo">${error}</div> <p>学号：<input type="text" size="20" name="stuNo"></p> <p>密码：<input type="password" size="20" name="stuPwd"></p> <p><input type="submit" value="登录"></p> </form> </body> </html> -
设置为首页：
web.xml添加
<!-- 设置欢迎页面 --> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list>
3. 编写dao层用户登陆的接口
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StudentDao
public interface StudentDao { //得到要登录的研究生 public Student getLoginStudent(Connection conn,String stuNo) throws SQLException; }
4. 编写dao接口的实现层
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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. 业务层接口
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StudentService
public interface StudentService { /** * 验证是否登录成功 * * @return 登录成功则返回用户对象，无则null */ public Student isLogin(String stuNo, String pwd) throws SQLException; }
6. 业务层实现类
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StudentServiceImpl
public class StudentServiceImpl implements StudentService { private StudentDao studentDao; public StudentServiceImpl() { studentDao = new StudentDaoImpl(); } /** * 验证是否登录成功 * * @return 有登录成功则返回用户对象，无则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. 编写Servlet
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StudentServlet
记得添加@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 { //获取客户端提交的数据 String stuNo = req.getParameter("stuNo"); String stuPwd = req.getParameter("stuPwd"); try { StudentService studentService = new StudentServiceImpl(); Student stu = studentService.isLogin(stuNo, stuPwd); if (stu != null) { //有该用户，存进session，跳转到查看导师页面 HttpSession session = req.getSession(); session.setAttribute(Constants.STUDENT_SESSION, stu); resp.sendRedirect("stu_check_tutor.jsp"); } else { //无该用户，跳转至登录页面，并提示错误信息 req.setAttribute("error", "用户名或密码不正确"); req.getRequestDispatcher("login.jsp").forward(req, resp); System.out.println("结束Servlet...."); } } catch (SQLException e) { e.printStackTrace(); } } }
