2020.10.24
一、今日学习内容
今天完成了Javaweb和数据库连接，课程录入的代码
aaa.jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> <style> .a{ margin-top: 20px; } .b{ font-size: 20px; width: 160px; color: white; background-color: greenyellow; } </style> </head> <body> <% Object message = request.getAttribute("message"); if(message!=null && !"".equals(message)){ %> <script type="text/javascript"> alert("<%=request.getAttribute("message")%>"); </script> <%} %> <div align="center"> <h1 style="color: red;">课程信息录入</h1> <a href="index.jsp">返回主页</a> <form action="${pageContext.request.contextPath }/addServlet" method="post" onsubmit="return check()"> <div class="a"> 课程名称<input type="text" id="name" name="name"/> </div> <div class="a"> 任课教师<input type="text" id="teacher" name="teacher" /> </div> <div class="a"> 上课地点<input type="text" id="classroom" name="classroom" /> </div> <div class="a"> <button type="submit" class="b">保 存<tton> </div> <tr> <td>学历：</td> <td> <input type="radio"name="degree"value="专科">专科 <input type="radio"name="degree"value="本科"checked>本科 <input type="radio"name="degree"value="硕士研究生">硕士研究生 <input type="radio"name="degree"value="博士研究生">博士研究生 <input type="radio"name="degree"value="其他">其他 </td> </tr> </form> </div> <script type="text/javascript"> function check() { var name = document.getElementById("name");; var teacher = document.getElementById("teacher"); var classroom = document.getElementById("classroom"); //非空 if(name.value == '') { alert('课程名称为空'); name.focus(); return false; } if(teacher.value == '') { alert('教师为空'); teacher.focus(); return false; } if(classroom.value == '') { alert('上课地点为空'); classroom.focus(); return false; } //教师 if(teacher.value != '王建民' && teacher.value != '王辉' && teacher.value != '刘丹' && teacher.value != '刘立嘉' && teacher.value != '杨子光'){ alert('教师名称错误'); return false; } //教室 if(!/^基教/.test(classroom.value) && !/^一教/.test(classroom.value) && !/^二教/.test(classroom.value) && !/^三教/.test(classroom.value)) { alert('上课地点错误'); return false; } } </script type="text/javascript">
DBUtil:
package DBUtil; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class DBUtil { public static String db_url = "jdbc:mysql://localhost:3306/test?serverTimezone=UTC"; public static String db_user = "root"; public static String db_pass = "08301016"; public static Connection getConn () { Connection conn = null; try { Class.forName("com.mysql.cj.jdbc.Driver"); conn = DriverManager.getConnection(db_url, db_user, db_pass); } catch (Exception e) { e.printStackTrace(); } return conn; }//end getConn public static void close (Statement state, Connection conn) { if (state != null) { try { state.close(); } catch (SQLException e) { e.printStackTrace(); } } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } public static void close (ResultSet rs, Statement state, Connection conn) { if (rs != null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if (state != null) { try { state.close(); } catch (SQLException e) { e.printStackTrace(); } } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } public static void main(String[] args) throws SQLException { Connection conn = getConn(); PreparedStatement pstmt = null; ResultSet rs = null; String sql ="select * from mmm"; pstmt = conn.prepareStatement(sql); rs = pstmt.executeQuery(); if(rs.next()){ System.out.println("连接成功"); }else{ System.out.println("连接失败"); } } }
Dao:
package Dao; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import DBUtil.DBUtil; import domain.Course; public class CourseDao { /** * 添加 * @param course * @return */ public boolean add(Course course) { String sql = "insert into mmm(name, teacher, classroom) values('" + course.getName() + "','" + course.getTeacher() + "','" + course.getClassroom() + "')"; Connection conn = DBUtil.getConn(); Statement state = null; boolean f = false; int a = 0; try { state = conn.createStatement(); state.executeUpdate(sql); } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.close(state, conn); } if (a > 0) { f = true; } return f; } }
domain:
package domain; public class Course { private String name; private String teacher; private String classroom; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getTeacher() { return teacher; } public void setTeacher(String teacher) { this.teacher = teacher; } public String getClassroom() { return classroom; } public void setClassroom(String classroom) { this.classroom = classroom; } public Course() {} public Course(String name, String teacher, String classroom) { this.name = name; this.teacher = teacher; this.classroom = classroom; } }
Servlet:
package servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import Dao.CourseDao; import domain.Course; /** * Servlet implementation class AddServlet */ @WebServlet("/addServlet") public class AddServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public AddServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub request.setCharacterEncoding("utf-8"); String name =request.getParameter("name"); String teacher = request.getParameter("teacher"); String classroom =request.getParameter("classroom"); Course course = new Course(name, teacher, classroom); CourseDao cd = new CourseDao(); //添加后消息显示 if(cd.add(course)) { request.getRequestDispatcher("aaa.jsp").forward(request,response); } else { request.getRequestDispatcher("aaa.jsp").forward(request,response); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
二、遇到的问题
对于代码中各个类的含义还不清楚，jsp中各部分的含义也不理解。
三、明日计划
继续学习Javaweb，了解各个函数代表的含义
