无法使用属性文件在Java中连接到MySql

Question

I Encountered a really strange problem I don't know how to handle.

My app connect to MySQL DB to fetch data, until yesterday I had the connection details hard coded in the code , and everything worked fine.

IE:

connect = DriverManager.getConnection("jdbc:mysql://10.0.0.188:3306", "dudug", "qazqaz");

I have decided to make my application more modular , and have an option to change/set the connection details, and store it in a property file.

Now when I use the following code:

Class.forName("com.mysql.jdbc.Driver");

// setup the connection with the DB.

String user = props.getProperty("SqlUserName");
String pass = props.getProperty("SqlPassword");
String port = String.valueOf(props.getProperty("SqlPort"));
String addr = props.getProperty("SqlAddress");
connect =  DriverManager.getConnection("\"jdbc:mysql://" + addr + ":" + port + "\",\"" + user + "\",\"" + pass + "\"");

, I get an error message like this :

java.sql.SQLException: No suitable driver found for "jdbc:mysql://10.0.0.188:3306?user=dudug&password=qazqaz"
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)

when debugging, both of the output connection strings are the same:

"jdbc:mysql://10.0.0.188:3306", "dudug", "qazqaz"

Only when I use the modular string I get a problem.

Anyone got any idea ?

Thnaks,

Dave.

UPDATE:

when is use this:

DriverManager.getConnection("jdbc:mysql://" + props.getProperty("SqlAddress") + ":" + String.valueOf(props.getProperty("SqlPort")) 
+ "," + props.getProperty("SqlUserName") + "," + props.getProperty("SqlPassword"));

or this:

String user = props.getProperty("SqlUserName");
String pass = props.getProperty("SqlPassword");
String port = String.valueOf(props.getProperty("SqlPort"));
String addr = props.getProperty("SqlAddress");

connect =  DriverManager.getConnection("jdbc:mysql://" + addr + ":" + port + "," + user + "," + pass);

its just gets stuck, posting no error message.

Answer 1

The problem is, that you are trying to build the parameters list of the getConnection() method.

"\"jdbc:mysql://" + addr + ":" + port + "\",\"" + user + "\",\"" + pass + "\"");

evaluates to

"jdbc:mysql://10.0.0.188:3306","dudug","qazqaz"

This is one String , even if it looks like a normal parameters list. Eg this gets called:

DriverManager.getConnection("\"jdbc:mysql://10.0.0.188:3306\",\"dudug\",\"quazquaz\"");

and not

DriverManager.getConnection("jdbc:mysql://10.0.0.188:3306", "dudug", "qazqaz");

What you want to do is:

String url = "jdbc:mysql://" + addr + ":" + port;
DriverManager.getConnection(url, user, password);

Answer 2

下载mysql-connector-java.jar并将其添加到您的类路径中。