《MySQL数据库》实训7-3 应用实例开发 答案

实训7-3应用实例开发导入stu.sql，在Ecplise中完成下列操作1.新建Java项目“MySQLDemo”。2.在MySQLDemo中导入连接mysql所需的JAR包mysql-connector-java-8.0.21.jar。3.编写Java程序实现对数据库stu中的数据表course的增删改查操作,并在控制台显示结果。（1）SQLYog中导入数据库stu右键单击左侧资源管理器空白处，选择【执行SQL脚本】在弹出的对话框中选择stu.sql的路径（2）新建Java项目，命名为MySQLDemo打开Ecplise，新建JavaProject（3）Java项目中导入数据库驱动（导入MySQL对应版本号的JAR包）在项目中新建lib目录将mysql-connector-java-8.0.21.jar复制到lib目录下，右键单击该文件右键，BuildPath->AddtoBuildPath（3）连接数据库DBUtil.java(对数据库进行连接)importjava.sql.*;publicclassDBUtil{ privatestaticStringjdbcName="com.mysql.cj.jdbc.Driver"; privatestaticStringdbUrl="jdbc:mysql://localhost:3306/stu?useSSL=false&serverTimezone=UTC"; privatestaticStringdbUserName="root"; privatestaticStringdbPassWord="123456"; //获取连接对象 publicstaticConnectiongetConn()throwsClassNotFoundException,SQLException{ Class.forName(jdbcName); Connectionconn=DriverManager.getConnection(dbUrl,dbUserName,dbPassWord); returnconn; } //释放资源 publicstaticvoidrelease(Statementstmt,Connectionconn){ if(stmt!=null){ try{ stmt.close(); }catch(SQLExceptione){ e.printStackTrace(); } stmt=null; } if(conn!=null){ try{ conn.close(); }catch(SQLExceptione){ e.printStackTrace(); } conn=null; } } publicstaticvoidrelease(ResultSetrs,Statementstmt,Connectionconn){ if(rs!=null){ try{ rs.close(); }catch(SQLExceptione){ e.printStackTrace(); } rs=null; } release(rs,stmt,conn); }}（4）对数据表进行操作Course.java(数据表course对应的实体类)publicclassCourse{ privateStringcno; privateStringcname; privateIntegerstart; privateFloatcredit; publicStringgetCno(){ returncno; } publicvoidsetCno(Stringcno){ o=cno; } publicStringgetCname(){ returncname; } publicvoidsetCname(Stringcname){ ame=cname; } publicIntegergetStart(){ returnstart; } publicvoidsetStart(Integerstart){ this.start=start; } publicFloatgetCredit(){ returncredit; } publicvoidsetCredit(Floatcredit){ this.credit=credit; } publicCourse(){} publicCourse(Stringcno,Stringcname,Integerstart,Floatd){ o=cno; ame=cname; this.start=start; this.credit=d; }}CourseDao.java（包含增删改查操作的方法）importjava.sql.*;publicclassCourseDao{ //查询表格中所有数据 publicstaticvoidselect()throwsException{ Connectionconn=DBUtil.getConn(); Stringsql="select*fromcourse"; PreparedStatementpstmt=(PreparedStatement)conn.prepareStatement(sql); ResultSetrSet=pstmt.executeQuery(); while(rSet.next()){//输出查询结果 Stringcno=rSet.getString("cno"); Stringcname=rSet.getString("cname"); Integerstart=rSet.getInt("start"); Floatcredit=rSet.getFloat("credit"); System.out.println(cno+""+cname+""+start+""+credit); } DBUtil.release(pstmt,conn); } //添加 publicstaticvoidadd(Coursecourse)throwsException{ Connectionconn=DBUtil.getConn(); Stringsql="insertintocoursevalues(?,?,?,?)"; PreparedStatementpstmt=(PreparedStatement)conn.prepareStatement(sql); pstmt.setString(1,course.getCno()); pstmt.setString(2,course.getCname()); pstmt.setInt(3,course.getStart()); pstmt.setFloat(4,course.getCredit()); inti=pstmt.executeUpdate(); if(i>0) select();//执行查询表格操作 else System.out.println("添加失败"); DBUtil.release(pstmt,conn); } //修改 publicstaticvoidupdate(Coursecourse)throwsException{ Connectionconn=DBUtil.getConn(); Stringsql="updatecoursesetcname=?,start=?,credit=?wherecno=?"; PreparedStatementpstmt=(PreparedStatement)conn.prepareStatement(sql); pstmt.setString(1,course.getCname()); pstmt.setInt(2,course.getStart()); pstmt.setFloat(3,course.getCredit()); pstmt.setString(4,course.getCno()); inti=pstmt.executeUpdate(); if(i>0) select();//执行查询表格操作 else System.out.println("修改失败"); DBUtil.release(pstmt,conn); } //删除 publicstaticvoiddelete(Stringcno)throwsException{ Connectionconn=DBUtil.getConn(); Stringsql="deletefromcoursewherecno=?"; PreparedStatementpstmt=(PreparedStatement)conn.prepareStatement(sql); pstmt.setString(1,cno); inti=pstmt.executeUpdate(); if(i>0) select();//执行查询表格操作 else System.out.println("删除失败"); DBUtil.release(pstmt,conn); }}（5）测试Test.java(测试类)importorg.junit.Test;publicclassMySQLTest{ @Test publicvoidt01()throwsException{ //数据查询 CourseDao.select(); } @Test publicvoidt02()throwsException{ //数据添加 Coursecourse=newCourse("07","JavaWeb",2,4.0f); System.out.println("************添加**********"); CourseDao.add(course); } @Test publicvoidt03()throwsException{ //数据修改 Coursecourse=newCourse("07","JSP",2,4.0f); Syst