java 连接MySQL数据库提取信息示例

快来打我* 2022-06-06 11:38 185阅读 0赞

import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.Scanner;
    
    public class 作业{
        public static void main(String[] args) {
            try {
                Class.forName("com.mysql.jdbc.Driver");
                Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/hair?useUnicode=true&characterEncoding=utf8","root","123456");
                String updateSql = "update student set 总分=英语+JavaSE程序设计+初级日语";
                PreparedStatement pst = conn.prepareStatement(updateSql);
                int zf = pst.executeUpdate();
                if (zf > 0)
                {
                    System.out.println("总分计算成功!");
                }
                System.out.println("************************");
                String showAll = "select * from student";
                PreparedStatement pst1 = conn.prepareStatement(showAll);
                ResultSet rs = pst1.executeQuery();
                while (rs.next())
                {
                    for (int i = 1;i <= 9;i++)
                    {
                        System.out.print(rs.getString(i)+" ");
                    }
                    System.out.println();
                }
                System.out.println("************************");
                String showFild = "select * from student where 英语<60 or JavaSE程序设计<60 or 初级日语 <60";
                PreparedStatement pst2 = conn.prepareStatement(showFild);
                ResultSet rsshouFild = pst2.executeQuery();
                while (rsshouFild.next())
                {
                    for (int i = 1;i <= 9;i++)
                    {
                        System.out.print(rsshouFild.getString(i)+" ");
                    }
                    System.out.println();
                }
                System.out.println("************************");
    
    
                System.out.println("Now you will alowed to import a line:");
    
                String insertLine = "insert into student(Id,学号,姓名,性别) values(?,?,?,?)";
    
                PreparedStatement pstInsert=conn.prepareStatement(insertLine);
    
                Scanner sc = new Scanner(System.in);
                System.out.println("请输入学生ID：");
                String id=sc.next();
                System.out.println("请输入学生学号：");
                String number=sc.next();
                System.out.println("请输入学生姓名：");
                String name=sc.next();
                System.out.println("请输入学生性别：");
                String sex=sc.next();
    
                pstInsert.setString(1, id);
                pstInsert.setString(2, number);
                pstInsert.setString(3, name);
                pstInsert.setString(4, sex);
                int y = pstInsert.executeUpdate();
                if(y>0)
                {
                    System.out.println("插入数据成功！");
                }
                System.out.println("************************");
    
    
                String updateBoyOld = "update student set 年龄=年龄+1 where 性别 ='男'";
                PreparedStatement pstupdateBoyOld = conn.prepareStatement(updateBoyOld);
                int boyplus = pstupdateBoyOld.executeUpdate();
                if (boyplus > 0)
                {
                    System.out.println("所有男学生年龄加 1成功！");
                }
                System.out.println("************************");
    
    
                String deleteSql="delete from student where 学号=?";
                PreparedStatement pstDelete=conn.prepareStatement(deleteSql);
                pstDelete.setString(1,"1005");
                int e = pstDelete.executeUpdate();
                if (e>0)
                {
                    System.out.println("删除成功！");
                }
                System.out.println("************************");
    
    
                String updateSoreDesc = "select * from student order by 总分 desc";
                PreparedStatement pstSoreDesc = conn.prepareStatement(updateSoreDesc);
                ResultSet rsSoreDesc = pstSoreDesc.executeQuery();
                while (rsSoreDesc.next())
                {
                    for (int i = 1;i <= 9;i++)
                    {
                        System.out.print(rsSoreDesc.getString(i)+" ");
                    }
                    System.out.println();
                }
    
            } catch (ClassNotFoundException e) {
    
                e.printStackTrace();
            } catch (SQLException e) {
    
                e.printStackTrace();
            }
    
    
        }
    
    }