在IDEA上实现简单的JDBC增删查改操作

在IDEA上实现简单的JDBC的增删查改操作，总的分为以下几步：
1.加载驱动
2.创建链接
3.写sql语句
4.得到statement对象
5.执行sql语句
6.处理结果集
7.关闭资源
下面开始详细的讲代码构成：
1.加载驱动

Class.forName("com.mysql.jdbc.Driver");

2.创建链接

connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/datename?useSSL=true&characterEncoding=utf-8&user=root&password=root");

datename为要连接数据库的名称，user为数据库用户名，password为数据库密码

以上两步是最基础的语句，大部分要操作数据库的都需要写这两个语句。

实现查找

import java.sql.*;

public class Test {
    public static void main(String[] args) {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        try{
            //1.加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2.创建连接
            connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/hjj?useSSL=true&characterEncoding=utf-8&user=root&password=123456");
            System.out.println("创建连接成功");
            //3.写sql
            String sql = "select * from tb_user";
            //4.得到statement对象
            preparedStatement = connection.prepareStatement(sql);
            //5.执行sql
            resultSet = preparedStatement.executeQuery();
            //6.处理结果集
            while (resultSet.next()){
                System.out.println(resultSet.getInt(1));
                System.out.println(resultSet.getString(2));
                System.out.println(resultSet.getString(3));
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //7.关闭资源
            try{
                connection.close();
            }catch (Exception e){
                e.printStackTrace();
            }
            try{
                preparedStatement.close();
            }catch (Exception e){
                e.printStackTrace();
            }
            try{
                resultSet.close();
            }catch (Exception e){
                e.printStackTrace();
            }
        }

    }

实现增加

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class Add {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try{
            //1.加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2.创建连接
            conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/hjj?useSSL=true&characterEncoding=utf-8&user=root&password=123456");
            System.out.println("增加操作");
            //3.写sql
            String sql = "insert into tb_user(username,password) "+"values('hjj1',1234)";
            //4.创建statement对象
            stmt = conn.createStatement();
            //5.执行sql
            stmt.executeUpdate(sql);
            //6.处理结果集
            System.out.println("成功插入数据");
        }catch (Exception e ){
            e.printStackTrace();
        }finally {
            try{
                stmt.close();
                conn.close();
            }catch (Exception e ){
                e.printStackTrace();
            }
        }

    }
}

实现修改

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class change {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try{
            //1.加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2.创建连接
            conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/hjj?useSSL=true&characterEncoding=utf-8&user=root&password=123456");
            System.out.println("修改");
            //4.创建statement对象
            stmt = conn.createStatement();
            //3.写sql
            String sql = "update tb_user set username='hhh' where username='hjj'";
            //5.执行sql
            stmt.executeUpdate(sql);
            //6.处理结果集
            System.out.println("修改成功");
        }catch (Exception e ){
            e.printStackTrace();
        }finally {
            try{
                stmt.close();
                conn.close();
            }catch (Exception e ){
                e.printStackTrace();
            }
        }
    }
}

实现删除

import java.awt.desktop.SystemEventListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class delete {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try{
            //1.加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2.创建连接
            conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/hjj?useSSL=true&characterEncoding=utf-8&user=root&password=123456");
            System.out.println("删除");
            //4.创建statement对象
            stmt = conn.createStatement();
            //3.写sql
            String sql = "delete from tb_user where username='hhh'";
            //5.执行sql
            stmt.executeUpdate(sql);
            //6.处理结果集
            System.out.println("成功删除");
        }catch (Exception e ){
            e.printStackTrace();
        }finally {
            try{
                stmt.close();
                conn.close();
            }catch (Exception e ){
                e.printStackTrace();
            }
        }
    }
}

在IDEA上实现简单的JDBC增删查改大部分代码都是类似的
，只需要修改SQL语句即可。