Connecting MySQL from JSP

问题

I just set foot on JSP. I started writing simple programs to display dates, system info. Then I tried to connect a MySQL database I have a free hosting account, but I am not able to connect to MySQL database. Here is my code:

<%@ page import="java.sql.*" %> 
<%@ page import="java.io.*" %> 
<html> 
<head> 
<title>Connection with mysql database</title>
</head> 
<body>
<h1>Connection status</h1>
<% 
try {
    String connectionURL = "jdbc:mysql://mysql2.000webhost.com/a3932573_product";
    Connection connection = null; 
    Class.forName("com.mysql.jdbc.Driver").newInstance(); 
    connection = DriverManager.getConnection(connectionURL, "a3932573_dibya", "******");
    if(!connection.isClosed())
         out.println("Successfully connected to " + "MySQL server using TCP/IP...");
    connection.close();
}catch(Exception ex){
    out.println("Unable to connect to database.");
}
%>
</font>
</body> 
</html>

I am getting Message as Connection Status unable to connect to database. I have tested this connection using PHP using the same username, password and database name. Where am I making mistake?

回答1:

Reason is the driver have not been loaded in the libraries, it does not get instantiated in the connection so the connection failed:

try {
            String connectionURL = "jdbc:mysql://host/db";
            Connection connection = null; 
            Class.forName("com.mysql.jdbc.Driver").newInstance(); 
            connection = DriverManager.getConnection(connectionURL, "username", "password");
            if(!connection.isClosed())
                 out.println("Successfully connected to " + "MySQL server using TCP/IP...");
            connection.close();
        }catch(Exception ex){
            out.println("Unable to connect to database"+ex);
        }

Download Driver

回答2:

I‘ve got the same problem. I'm pretty much sure what's wrong with your program: you haven't added .jar to web lib. Copy it and paste into WEB-INF/lib.

Sorry for not using the correct format for posting answers(I'm new here and this is my first anwser:( )

回答3:

Download the right driver :

http://dev.mysql.com/downloads/connector/j/

And add the jar in the classpath of your project.

来源：https://stackoverflow.com/questions/13505833/connecting-mysql-from-jsp

标签

mysql

jsp

database-connection