数据库增删改查

import java.sql.*;

public class Renewal { // 创建类
static Connection con; // 声明Connection对象
static PreparedStatement sql; // 声明PreparedStatement对象
static ResultSet res; // 声明ResultSet对象

public Connection getConnection() {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/db?useSSL=false&serverTimezone=GMT","root","020714");
} catch (Exception e) {
e.printStackTrace();
}
return con;
}

public static void main(String[] args) {
Renewal c = new Renewal(); // 创建本类对象
con = c.getConnection(); // 调用连接数据库方法
try {
sql = con.prepareStatement("select * from tb_stu"); // 查询数据库
res = sql.executeQuery(); // 执行SQL语句
System.out.println("执行增加、修改、删除前数据:");
while (res.next()) {
String id = res.getString(1);
String name = res.getString("name");
String sex = res.getString("sex");
String birthday = res.getString("birthday"); // 遍历查询结果集
System.out.print("编号：" + id);
System.out.print(" 姓名：" + name);
System.out.print(" 性别:" + sex);
System.out.println(" 生日：" + birthday);
}
sql = con.prepareStatement("insert into tb_stu(name,sex,birthday) values(?,?,?)");
sql.setString(1, "阿杰"); // 预处理添加数据
sql.setString(2, "男");
sql.setString(3, "2001-03-08");
sql.executeUpdate();
sql = con.prepareStatement("update tb_stu set birthday "
+ "= ? where id = ? ");
sql.setString(1, "2012-12-02"); // 更新数据
sql.setInt(2, 1); // 更新数据
sql.executeUpdate();
Statement stmt = con.createStatement();
stmt.executeUpdate("delete from tb_stu where id = 9");//删除
// 查询修改数据后的tb_stu表中数据
sql = con.prepareStatement("select * from tb_stu");
res = sql.executeQuery(); // 执行SQL语句
System.out.println("执行增加、修改、删除后的数据:");
while (res.next()) {
String id = res.getString(1);
String name = res.getString("name");
String sex = res.getString("sex");
String birthday = res.getString("birthday");
System.out.print("编号：" + id);
System.out.print(" 姓名：" + name);
System.out.print(" 性别:" + sex);
System.out.println(" 生日：" + birthday);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}