JDBC的增删改查基本操作

package JDBC_1;
//演示jdbc所使用的预编译

import java.sql.*;

public class jdbc_2 {
    private static Connection coon = null;

    static {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            coon = DriverManager.getConnection(
                    "jdbc:mysql://127.0.0.1:3306/jdbc_4", "root", "root"
            );
        } catch (Exception e) {
            System.out.println("数据库连接失败");
        }
    }

    public static void main(String[] args) throws Exception {
        System.out.println(coon);
        //数据库操作
        //查询
        select(coon);
        //增加调用
        insert();
        select(coon);
        //修改调用
        update();
        select(coon);
        //删除调用
        delete();
        select(coon);
    }

    //删除用法
    public static void delete() {
        String sql = "delete from user where id =?";
        PreparedStatement ps = null;
        try {
            ps = coon.prepareStatement(sql);
            //后面的数字是表示删除ID为几的行列
            ps.setInt(1, 1);
        } catch (Exception e) {
            System.err.println("SQL预处理失败");
        }
        try {
            ps.execute();
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("删除陈功了");
        }
    }

    //修改
    public static void update() {

        String sql = "update user set nane =?," + " phone=?,em=? where id=? ";
        PreparedStatement ps = null;
        try {
            ps = coon.prepareStatement(sql);
            ps.setString(1, "小六子");
            ps.setString(2, "66666");
            ps.setString(3, "333");
            ps.setInt(4, 6);
            ps.execute();
        } catch (Exception e) {
            System.err.println("sql修改解析异常");
        }
        try {
            ps.execute();
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("修改失败");
        }
    }

    //增加
    public static void insert() {
        String sql = "insert into user (nane,phone,em) value (?,?,?)";
        PreparedStatement ps = null;
        //获取编译对象并对sql语句进行预处理
        try {
            ps = coon.prepareStatement(sql);
            ps.setString(1, "小阿涛");
            ps.setString(2, "175");
            ps.setString(3, "999");
        } catch (Exception e) {
            System.out.println("SQL预处理异常");
        }
        try {
            ps.execute();
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("SQl执行异常");
        }
    }

    public static void select(Connection connection) throws Exception {
        //3:操作数据库
        //3.1查询
        String sql = "select * from user";
        //sql操作器
        //获取sql操作器
        Statement statement = connection.createStatement();
        //3.3使用操作器执行查询并获取结果集
        ResultSet resultSet = statement.executeQuery(sql);
        //3.4解析结果集
        System.out.println("id \t nane \tphone \tem");
        while (resultSet.next()) {
            int id = resultSet.getInt("id");
            String nane = resultSet.getString("nane");
            String phone = resultSet.getString("phone");
            String em = resultSet.getString("em");
            System.out.println(id + "\t" + nane + "\t" + phone + "\t" + em);
        }
    }
}