java-jdbc简单应用-优快云博客

本文介绍了一个使用Java JDBC进行数据库操作的示例，包括连接数据库、执行SQL语句、插入、更新、删除记录以及创建新表。同时，示例展示了如何使用ResultSet处理查询结果。

在数据库db3中操作account表，account表只有两个字段id和balcane

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBCDemo2 {
    /**
     * 1.account表 添加一条记录
     * 2.account 修改一条记录
     * 3.account 删除一条记录
     * 4.创建student表
     * */
    public static void main(String[] args){
        Statement stmt = null;
        Connection conn = null;
       try{
           //1.导入驱动jar包
           //2.注册驱动
           Class.forName("com.mysql.cj.jdbc.Driver");
           //3.获取数据库连接对象
           conn = DriverManager.getConnection(
                   "jdbc:mysql://localhost:3306/db3?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC",
                   "root",
                   "root");
           //4.定义sql语句
           String sql = "insert into account values(null , 200)";//添加一条记录
           String sql1 = "update account set balance = 2000 where id = 2;";//修改一条记录
           String sql2 = "delete from account where id = 2;"; //删除一条记录
           String sql3 = "create table student (id int , name varchar(20))";
           //5.获取执行sql对象Statement
           stmt = conn.createStatement();
           //6.执行sql
           int count = stmt.executeUpdate(sql3);//返回影响的行数
           //7.处理结果
           System.out.println(count);
       }catch (ClassNotFoundException e){
           e.printStackTrace();
       }catch (SQLException e){
           e.printStackTrace();
       }finally {
           //8.释放资源
           if(stmt != null){
               try {
                   stmt.close();
               } catch (SQLException e) {
                   e.printStackTrace();
               }
           }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
       }
    }
}

ResultSet的使用

package cn.hds.jdbc;
import java.sql.*;
public class JDBCDeom3 {
    public static void main(String[] args) {
        Statement stmt = null;
        Connection conn = null;
        ResultSet rs = null;
        try {
            //1.导入驱动jar包
            //2.注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //3.获取数据库连接对象
            conn = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/db3?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC",
                    "root",
                    "root");
            //4.定义sql语句
            String sql = "select * from account;";//添加一条记录
            //5.获取执行sql对象Statement
            stmt = conn.createStatement();
            //6.执行sql
            rs = stmt.executeQuery(sql);//返回影响的行数
            //7.处理结果
            while (rs.next()){//7.1让游标向下移动一行
                //7.2 获取数据
                int id = rs.getInt(1);
                int balance = rs.getInt("balance");
                System.out.println(id + "-----" + balance);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            //8.释放资源
            if(rs != null){
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}