Java connect to MySQL

Use of the environment

• jdk 1.8
• mysql 8.0
• idea 2019

Specific process

1, custom installation mysql, you need to check Connector / J.

You can then install directory C:\Program Files (x86)\MySQL\Connector J 8.0to find the next

mysql-connector-java-8.0.15.jar jar package, that is connected to the driver java mysql.

2, will be copied to the jre lib directory driver.

That is, mysql-connector-java-8.0.15.jarcopied to

C:\Program Files\Java\jdk1.8.0_211\jre\lib in

3, using the idea to create a new empty ordinary java project

Then File -> Project Structure, or Ctrl+Alt+Shift+Sopen the window as shown below:

4, a new data table in the database

/*
Navicat MySQL Data Transfer

Source Server         : @localmysql
Source Server Version : 80015
Source Host           : localhost:3306
Source Database       : javademo

Target Server Type    : MYSQL
Target Server Version : 80015
File Encoding         : 65001

Date: 2019-05-28 16:25:05
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for student
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(255) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `age` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '张三', '165');
INSERT INTO `student` VALUES ('2', '历史', '45');
INSERT INTO `student` VALUES ('3', '浮点', '32');
INSERT INTO `student` VALUES ('4', '法法', '54');

5, the preparation of the database connection java code

package com.tuweiwei;

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

public class demo01 {
    public static void main(String[] args) {

        // Connection 是java.sql包下的类，表示数据库连接
        Connection conn;
        // 驱动程序名
        String driver = "com.mysql.cj.jdbc.Driver";
        // 指定要连接的数据库，这里我的数据库名为 javademo
        String jdbcUrl = "jdbc:mysql://localhost:3306/javademo?serverTimezone=UTC";
        // 数据库用户名
        String userName = "root";
        // 数据库密码
        String userPwd = "111111";

        try {
            // 加载驱动程序
            Class.forName(driver);
            // 连接数据库
            conn = DriverManager.getConnection(jdbcUrl, userName, userPwd);
            if (!conn.isClosed()) {
                System.out.println("Succeeded connecting to the Database!");
            }
            // java.sql包的Statement类，表示数据库的语句
            Statement statement = conn.createStatement();
            // 真实的SQL代码
            String sql = "select * from t_test_user";
            // java.sql包的ResultSet类，表示数据库的查询结果集
            ResultSet rs = statement.executeQuery(sql);
            String name = null;
            String age = null;
            while (rs.next()) {
                name = rs.getString("name");
                age = rs.getString("age");
                System.out.println(name+"\t"+age);
            }
            rs.close();
            conn.close();
        }
        catch (Exception e){
            System.out.println(e);
        }
    }
}

Problems encountered

1, the driver package is installed mysql com.mysql.jdbc.Driver be changed after 8.0 com.mysql.cj.jdbc.Driver

2、java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time

Area Error prompt system can execute commands in mysql:
SET Global TIME_ZONE = '+ 8:00'
or add serverTimezone = UTC parameter in the database-driven url