2. 访问 MySQL

2.1 Java —— JDBC

public class JavaVisitMySQL {

  	public static final String URL = "jdbc:mysql://localhost:3306/database";
    public static final String USERNAME = "xxxx";
    public static final String PASSWORD = "xxxx";

    public static void main(String[] args) throws Exception {
        //1. 加载驱动程序
        Class.forName("com.mysql.jdbc.cj.Driver");
        //2. 获得数据库连接
        Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
        //3. 操作数据库，实现增删改查
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT user_name, user_age FROM tbl_user");
        // 如果有数据，rs.next() 返回 true
        while(rs.next()){
            System.out.println(rs.getString("user_name")+" 年龄："+rs.getInt("user_age"));
        }
    }
}

2.2 Golang —— go-sql-driver

下载依赖

• go get -u github.com/go-sql-driver/mysql

package main

import (
	"database/sql"
	"fmt"
	"strings"
	// 需要引入
	_ "github.com/go-sql-driver/mysql"
)

// 数据库配置
const (
	MYSQL_USERNAME = "root"
	MYSQL_PASSWORD = "123456"
	MYSQL_HOSTNAME = "localhost"
	MYSQL_PORT = "3306"
	MYSQL_DB_NAEM = "myblog"
)

// 数据库连接池
var dbPool *sql.DB

func main() {
	// 连接数据库：username:password@tcp(hostname:port)/dbName?charset=utf8
	dbPath := strings.Join([]string{MYSQL_USERNAME,":",MYSQL_PASSWORD,"@tcp(",MYSQL_HOSTNAME,":",MYSQL_PORT,")/",MYSQL_DB_NAEM,"?charset=utf8"},"")
	// 打开数据库
	dbPool, err := sql.Open("mysql", dbPath)
	if err != nil {
		fmt.Println("open mysql failed, err:", err.Error())
		return
	}
	// 关闭连接
	defer dbPool.Close()
	// 验证连接
	if err = dbPool.Ping(); err != nil {
		fmt.Println("ping mysql failed, err:", err.Error())
		return
	}
	fmt.Println("ping mysql success")
	// 读取数据
	sql := "select * from blogs;"
	result, err := dbPool.Query(sql)
	if err != nil {
		fmt.Println("query sql failed, err:", err.Error())
		return
	}
	// 循环读取结果
	row := &struct {
		Id int
		Title string
		Content string
		Author string
	}{}
	for result.Next() {
		err = result.Scan(&row.Id, &row.Title, &row.Content, &row.Author)
		if err != nil {
			fmt.Println("scan data failed, err:", err.Error())
			return
		}
		fmt.Println("row:", row)
	}
}