JDBC原生态连接数据操作的问题. - 黑马程序员技术交流社区

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 Jdbc {
public static void main(String[] args) throws SQLException {
PreparedStatement pst = null;
ResultSet rs = null;
Scanner sin = new Scanner(System.in);
boolean flag = true;
// 数据库连接
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/jdbc", "root", "123456");
} catch (SQLException | ClassNotFoundException e1) {
e1.printStackTrace();
}
// 数据库操作
System.out.println("=================================");
System.out.println(" 0 结束 1 查询（女） 2 查询（男） 3 添加 4 删除 ");
System.out.println("=================================");
while (flag) {
System.out.println("请输入操作序号");
switch (sin.next()) {
case "0":
flag = false;
break;
case "1":
try {
pst = conn
.prepareStatement("select * from t_user where sex='女'");
rs = pst.executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}
if(rs != null) {
while (rs.next()) {
String str = "ID：" + rs.getString(1) + " 姓名：" + rs.getString(2)
+ " 性别：" + rs.getString(3);
System.out.println(str);
}
}
break;
case "2":
try {
pst = conn
.prepareStatement("select * from t_user where sex='男'");
rs = pst.executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}
if(rs != null) {
while (rs.next()) {
String str = "ID：" + rs.getString(1) + " 姓名：" + rs.getString(2)
+ " 性别：" + rs.getString(3);
System.out.println(str);
}
}
break;
case "4":
System.out.println("请输入学号：");
try {
pst = conn
.prepareStatement("delete from t_user where id=?");
pst.setInt(1, Integer.valueOf(sin.next()));
int result = pst.executeUpdate();
if(result != 0) {
System.out.println("删除成功！");
}
} catch (SQLException e) {
e.printStackTrace();
}
if(rs != null) {
while (rs.next()) {
String str = "ID：" + rs.getString(1) + " 姓名：" + rs.getString(2)
+ " 性别：" + rs.getString(3);
System.out.println(str);
}
}
break;
case "3":
try {
pst = conn
.prepareStatement("insert t_user(id,name,sex) values(?,?,?)");
System.out.println("请输入学号：");
pst.setInt(1,Integer.valueOf(sin.next()));
System.out.println("请输入姓名：");
pst.setString(2,sin.next());
System.out.println("请输入性别：");
pst.setString(3,sin.next());
int result = pst.executeUpdate();
if(result != 0) {
System.out.println("增加成功！");
}
} catch (SQLException e) {
e.printStackTrace();
}
if(rs != null) {
while (rs.next()) {
String str = "ID：" + rs.getString(1) + " 姓名：" + rs.getString(2)
+ " 性别：" + rs.getString(3);
System.out.println(str);
}
}
break;
default:
System.out.println("输入无效，请重新输入！");
}
}
conn.close();
pst.close();
rs.close();
sin.close();
}
}

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