如何使用JDBC连接XAMPP MySQL本地数据库？

I have this Tetris game written in Java, which uses DB to record high scores. It worked ok as long as I was using remote MySQL DB, but now I'm trying to set up localhost DB using XAMPP MySQL and it keeps going like "SQLException: Communications link failure" at command:

我有这个用Java编写的俄罗斯方块游戏,它使用DB来记录高分。只要我使用远程MySQL数据库就可以正常工作,但现在我正在尝试使用XAMPP MySQL设置localhost数据库,并且它在命令中继续像“SQLException:Communications link failure”:

con = java.sql.DriverManager.getConnection("jdbc:mysql://localhost/score", user, psw);

I guess it's either wrong URL or DB configuration, but I really don't know what to check. Any ideas?

我想这是错误的URL或数据库配置,但我真的不知道要检查什么。有任何想法吗?

EDIT: My friend has fixed my problem by replacing "localhost" in URL by "127.0.0.1" (which was quite embarrassing as you can surely imagine :P ).

编辑:我的朋友已修复我的问题,将URL中的“localhost”替换为“127.0.0.1”(这非常令人尴尬,因为你可以想象:P)。

So question is: Why is XAMPP not able to translate "localhost" into IP address and how to fix it?

所以问题是:为什么XAMPP无法将“localhost”转换为IP地址以及如何修复它?

3 个解决方案

#1

Why is XAMPP not able to translate "localhost" into IP address and how to fix it?

为什么XAMPP无法将“localhost”转换为IP地址以及如何修复它?

This is not a XAMPP problem nor a programming problem. This is more a DNS problem.

这不是XAMPP问题,也不是编程问题。这更像是一个DNS问题。

To start, do you have a %SystemRoot%/system32/drivers/etc/hosts file with the following line as first line? (thus, after all comments, but before any other host declarations)

首先,您是否有一个%SystemRoot%/ system32 / drivers / etc / hosts文件,第一行是以下行? (因此,在所有评论之后,但在任何其他主持人声明之前)

127.0.0.1 localhost

Update: as per the comments I've Googled a bit and it look like that the MySQL JDBC driver doesn't eat IPv6 addresses at all. In other words, you'll need to change ::1 to 127.0.0.1. But I also found this topic which mentions that you can use the following JVM argument to fix this problem:

更新:根据评论我已经谷歌搜索了一下,看起来MySQL JDBC驱动程序根本不吃IPv6地址。换句话说,您需要将:: 1更改为127.0.0.1。但我也发现这个主题提到您可以使用以下JVM参数来解决此问题:

java -Djava.net.preferIPv4Stack=true

#2

I tried and got a successful connection. First create a database in phpmyadmin - eg. 'mydb' and then in code put connection.url with this value

我试过并成功连接。首先在phpmyadmin中创建一个数据库 - 例如。 'mydb'然后在代码中将connection.url与此值放在一起

'jdbc:mysql://localhost:3306/mydb'

If you don't create a database first it wont connect

如果您不首先创建数据库,它将不会连接

#3

In MySql you have to allow access for your user from localhost explicitly. Here is an example (taken from here):

在MySql中,您必须允许显式地从localhost访问您的用户。这是一个例子(取自这里):

mysql> grant usage on *.* to amarokuser@localhost identified by 'amarokpasswd';
mysql> grant all privileges on amarokdb.* to amarokuser@localhost ;

#1