大数据之路week05--day01（JDBC 初识之实现一个系统 实现用户选择增删改查 未优化版本）

要求，实现用户选择增删改查。

给出mysql文件，朋友们可以自己运行导入到自己的数据库中：

/*
Navicat MySQL Data Transfer

Source Server         : mysql
Source Server Version : 50557
Source Host           : 127.0.0.1:3306
Source Database       : school

Target Server Type    : MYSQL
Target Server Version : 50557
File Encoding         : 65001

Date: 2019-12-02 21:20:56
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for t_student
-- ----------------------------
DROP TABLE IF EXISTS `t_student`;
CREATE TABLE `t_student` (
  `sid` int(11) NOT NULL,
  `sname` varchar(10) NOT NULL,
  `gender` varchar(2) NOT NULL,
  `Classid` int(11) NOT NULL,
  PRIMARY KEY (`sid`),
  UNIQUE KEY `UK_SNAME` (`sname`),
  KEY `UF_SCLASS` (`Classid`),
  CONSTRAINT `UF_SCLASS` FOREIGN KEY (`Classid`) REFERENCES `t_class` (`cid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of t_student
-- ----------------------------
INSERT INTO `t_student` VALUES ('', '埼玉', '男', '');
INSERT INTO `t_student` VALUES ('', '李宏灿', '男', '');
INSERT INTO `t_student` VALUES ('', '娘口三三', '男', '');
INSERT INTO `t_student` VALUES ('', '路飞', '男', '');
INSERT INTO `t_student` VALUES ('', '齐博源', '男', '');
INSERT INTO `t_student` VALUES ('', '比较好', '男', '');
INSERT INTO `t_student` VALUES ('', '赵以浩', '男', '');
INSERT INTO `t_student` VALUES ('', '大雄', '男', '');

系统实现代码：

 package MySQL测试连接;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Scanner;

 /**
  *
  * 创建时间：2019年12月2日 上午10:11:28
  *
  * 项目名称：MySQL_Test
  *
  * @author WYH
  *
  * @version 1.0
  *
  * @since JDK 1.8.0
  *
  *        文件名称：Test5.java
  *
  *        类说明：
  *            对数据库操作的增删改查系统1.0版本
  */

 public class Test5 {
     private static Connection conn = null;
     private static PreparedStatement ps = null;
     private static ResultSet rs = null;

     // 添加
     public static void insertSql(String sql, Connection conn, int sid,
             String sname, String gender, int Classid) {
         try {
             ps = conn.prepareStatement(sql);
             ps.setInt(1, sid);
             ps.setString(2, sname);
             ps.setString(3, gender);
             ps.setInt(4, Classid);
             int i = ps.executeUpdate();
             System.out.println("有" + i + "记录被影响,成功添加一条数据！");
         } catch (Exception e) {
             System.out.println("添加失败！！");
         }

     }

     // 查询
     public static void selectSql(String SelectSql, Connection conn) {
         try {
             ps = conn.prepareStatement(SelectSql);
             // ps.setString(1, "男");
             rs = ps.executeQuery();
             System.out.println("学号\t\t姓名\t性别\t所在班级");
             while (rs.next()) {
                 System.out.println(rs.getString(1) + "\t" + rs.getString(2)
                         + "\t" + rs.getString(3) + "\t" + rs.getString(4));
             }
         } catch (Exception e) {
             System.out.println("查询失败!!");
         }

     }

     // 删除
     public static void deleteSql(String DeleteSql, Connection conn, int sid1) {
         try {
             ps = conn.prepareStatement(DeleteSql);
             ps.setInt(1, sid1);
             int j = ps.executeUpdate();
             System.out.println("有" + j + "条数据被影响,成功的删除" + sid1 + "数据");
         } catch (Exception e) {
             System.out.println("删除失败!!");
         }
     }

     // 更新
     public static void updateSql(String UpdateSql, Connection conn,
             String sname2, int sid2) {
         try {
             ps = conn.prepareStatement(UpdateSql);
             ps.setString(1, sname2);
             ps.setInt(2, sid2);
             int i = ps.executeUpdate();
             System.out.println("有" + i + "条数据被影响,成功更新数据。。");
         } catch (Exception e) {
             System.out.println("更新失败!!");
         }
     }

     public static void start() {
         boolean flag = true;
         Scanner sc = new Scanner(System.in);
         System.out.println("===========欢迎使用t_student表的操作系统===========");
         while (flag) {
             System.out.println("1、添加数据\n2、查询数据\n3、更新数据\n4、删除数据\n5、退出");
             System.out.print("请选择您需要的操作:");
             int choice = sc.nextInt();

             switch (choice) {
             case 1:
                 // 添加数据
                 String sql = "insert into t_student(sid,sname,gender,Classid) values(?,?,?,?)";
                 System.out.print("请输入您要添加学号:");
                 int sid = sc.nextInt();

                 System.out.print("请输入您添加学生的姓名:");
                 String sname = sc.next();

                 System.out.print("请输入您添加学生的性别:");
                 String gender = sc.next();

                 System.out.print("请输入您添加学生的班级号:");
                 int Classid = sc.nextInt();
                 insertSql(sql, conn, sid, sname, gender, Classid);

                 System.out.println("添加后的数据为:");
                 selectSql("select * from t_student", conn);
                 System.out.println();
                 System.out.println();
                 break;

             case 2:
                 // 查询数据
                 String SelectSql = "select * from t_student";
                 selectSql(SelectSql, conn);
                 System.out.println();
                 System.out.println();
                 break;

             case 3:
                 // 更新数据
                 String UpdateSql = "update t_student set sname=? where sid=? ";
                 System.out.print("请输入要更新姓名的学生学号:");
                 int sid2 = sc.nextInt();

                 System.out.print("请输入要更新该学号的新姓名:");
                 String sname2 = sc.next();
                 updateSql(UpdateSql, conn, sname2, sid2);

                 System.out.println("更新后的数据为:");
                 selectSql("select * from t_student", conn);
                 System.out.println();
                 System.out.println();
                 break;

             case 4:
                 // 删除
                 String DeleteSql = "delete from t_student where sid=?";
                 System.out.print("请输入要删除的学生学号:");
                 int sid1 = sc.nextInt();
                 deleteSql(DeleteSql, conn, sid1);

                 System.out.println("删除后的数据为:");
                 selectSql("select * from t_student", conn);
                 System.out.println();
                 System.out.println();
                 break;
             case 5:
                 System.out.println("谢谢使用");
                 flag = false;
                 break;
             default:
                 System.out.println("输入有误。。请重新输入");
                 System.out.println();
                 System.out.println();
                 break;
             }
         }

     }

     public static void main(String[] args) {
         try {
             Class.forName("com.mysql.jdbc.Driver");
             conn = DriverManager.getConnection(
                     "jdbc:mysql://127.0.0.1:3306/school", "root", "root");
             System.out.println(conn);
             start();

         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         } catch (SQLException e) {
             e.printStackTrace();
         } finally {
             if (rs != null) {
                 try {
                     rs.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
             if (ps != null) {
                 try {
                     ps.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
             if (conn != null) {
                 try {
                     conn.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }
         }

     }

 }

运行结果：