《Java程序设计》实验报告（六）之在JSP中操作数据库
| 实验内容及步骤：
package lyx.study.jsp.dao; import lyx.study.jsp.entity.Course; import java.sql.*; import java.util.ArrayList; import java.util.List; public class CourseDao { private Connection conn ; private PreparedStatement pstmt; private ResultSet rs; public List { try { Class.forName("com.mysql.cj.jdbc.Driver"); conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/mysql" + "?serverTimezone=UTC&useUnicode" + "=true&characterEncoding=utf8&useSSL=true", "root", "root"); String sql = "select * from course"; pstmt = conn.prepareStatement(sql); //执行查询用executeQuery() rs = pstmt.executeQuery(); Course course = null; List while(rs.next()) { 实验内容及步骤： course = new Course( rs.getInt(1), rs.getString(2), rs.getString(3), rs.getDouble(4), rs.getString(5), rs.getString(6) ); courseList.add(course); } return courseList; }catch (ClassNotFoundException cfe) { cfe.printStackTrace(); System.out.println("数据库驱动加载失败!"); }catch (SQLException sqle) { sqle.printStackTrace(); System.out.println("获取数据库链接失败!"); } return null; } public Integer insertCourse(Course course) { try { Class.forName("com.mysql.cj.jdbc.Driver"); conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/mysql", "root", "root"); String sql = "insert into course values(?,?,?,?,?,?)"; pstmt = conn.prepareStatement(sql); //执行查询用executeQuery() pstmt.setInt(1,course.getCid()); pstmt.setString(2,course.getCno()); pstmt.setString(3,course.getCname()); pstmt.setDouble(4,course.getCscore()); pstmt.setString(5, course.getCtno()); pstmt.setString(6,course.getCtype()); 实验内容及步骤： int count = pstmt.executeUpdate(); return count; }catch (ClassNotFoundException cfe) { cfe.printStackTrace(); System.out.println("数据库驱动加载失败!"); }catch (SQLException sqle) { sqle.printStackTrace(); System.out.println("获取数据库链接失败!"); } return 0; } } package lyx.study.jsp.entity; import java.util.Objects; public class Course { private Integer cid; private String cno; private String cname; private Double cscore; private String ctno; private String ctype; public Course() { } public Course(Integer cid, String cno, String cname, Double cscore, String ctno, String ctype) { this.cid = cid; this.cno = cno; this.cname = cname; this.cscore = cscore; this.ctno = ctno; this.ctype = ctype; } public Integer getCid() { return cid; 实验内容及步骤： } public void setCid(Integer cid) { this.cid = cid; } public String getCno() { return cno; } public void setCno(String cno) { this.cno = cno; } public String getCname() { return cname; } public void setCname(String cname) { this.cname = cname; } public Double getCscore() { return cscore; } public void setCscore(Double cscore) { this.cscore = cscore; } public String getCtno() { return ctno; } public void setCtno(String ctno) { this.ctno = ctno; } public String getCtype() { return ctype; } public void setCtype(String ctype) 实验内容及步骤： { this.ctype = ctype; } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof Course)) return false; Course course = (Course) o; return Objects.equals(cid, course.cid) && Objects.equals(cno, course.cno) && Objects.equals(cname, course.cname) && Objects.equals(cscore, course.cscore) && Objects.equals(ctno, course.ctno) && Objects.equals(ctype, course.ctype); } @Override public int hashCode() { return Objects.hash(cid, cno, cname, cscore, ctno, ctype); } } package lyx.study.jsp.service; import lyx.study.jsp.dao.CourseDao; import lyx.study.jsp.entity.Course; import java.util.List; public class CourseService { private CourseDao courseDao; public CourseService() { courseDao = new CourseDao(); } //处理查询所有课程的业务 public List { return courseDao.selectAll(); } public Integer addCourse(Course course) { 实验内容及步骤： return courseDao.insertCourse(course); } } package lyx.study.jsp.Servlet; 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 java.io.IOException; @WebServlet("/addCourse") public class AddCourseServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.sendRedirect(req.getContextPath() + "/addCourse.jsp"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } } package lyx.study.jsp.Servlet; import lyx.study.jsp.entity.Course; import lyx.study.jsp.service.CourseService; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.util.List; public class AllCourseServlet extends HttpServlet 实验内容及步骤： { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); CourseService courseService = new CourseService(); List //用的请求作用域：在一次请求内，数据可以用请求域（request）进行流转 req.setAttribute("courseList",courseList); req.getRequestDispatcher("allCourse.jsp").forward(req,resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } } package lyx.study.jsp.Servlet; import lyx.study.jsp.entity.Course; import lyx.study.jsp.service.CourseService; 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 java.io.IOException; @WebServlet("/saveCourse") public class SaveCourseServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String cno = req.getParameter("cno"); 实验内容及步骤： String cname = req.getParameter("cname"); String cscore = req.getParameter("cscore"); String ctno = req.getParameter("ctno"); String ctype = req.getParameter("ctype"); Course course = new Course( 0 , cno , cname, Double.parseDouble(cscore), ctno, ctype); CourseService courseService = new CourseService(); Integer i = courseService.addCourse(course); if (i > 0){ System.out.println("添加成功！"); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } } xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> 实验内容及步骤：
添加Course信息！
<% List if (courseList != null){ %>
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| 实验内容及步骤： |
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| 你的问题：
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