Java连接Mysql常用命令及模板

查看table内容：

select * from table_name
select * from table_name [ where condition ]
           

创建table：

create table admin (`time` date ,`pl` varchar(6));
create table root like admin;
           

增删改查：

delete from userlist where id="";
update a1 set `8`='user1' where `date`=date(date_add(now(),interval 0 day));
update a2 set `8` = null;
alter table admin add column t int;
delete from user2 where `time`=2018-12-23 and `pl`='a3' and `t`=null;
           

java连接mysql模板：

package com;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.*;
import java.util.Calendar;
import java.util.GregorianCalendar;
import com.cnt;
import com.sun.javafx.binding.StringFormatter;

public class class_name extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        PrintWriter out=response.getWriter();
        response.setContentType("text");
        try {
            Connection con;
            Statement stmt;
            ResultSet rs;
            Class.forName("com.mysql.jdbc.Driver");
            String dbUrl = "jdbc:mysql://localhost:3306/database_name?serverTimezone=GMT%2B8";
            String dbUser = "XXX";
            String dbPwd = "******";
            con = java.sql.DriverManager.getConnection(dbUrl, dbUser, dbPwd);
            stmt = con.createStatement();
            rs=stmt.executeQuery("select * from table_name");
            while (rs.next()){
            /*
                balabalabala
            */
            }
            rs.close();
            stmt.close();
            con.close();
        } catch (
                Exception e) {
            out.println(e.getMessage());
        }
    }
}