尝试使用JSP页面连接到MySql时出现错误

Question

I am unable to connect to MySql using JSP page. This is my connection query -

<%
String driver = "com.mysql.jdbc.Driver";
Class.forName("Driver").newInstance();
Connection con=null;
ResultSet rst=null;
Statement stmt=null;
con=DriverManager.getConnection("jdbc:mysql://10.1.11.103:3306/jiradb40","opsrptusr", "opsrptusr");
stmt=con.createStatement();

String query = "(select * from jiraissue limit 2)";
%>

I have placed jar file in lib folder still getting the error.

Any help is well appreciated.

---

Exception report

 message An exception occurred processing JSP page /Worklog.jsp at line 5

 description The server encountered an internal error that prevented it from fulfilling this request.

 exception 
 org.apache.jasper.JasperException: An exception occurred processing JSP page /Worklog.jsp at line 5

2: <%@page import="java.text.DecimalFormat" %>
3:  <%
4: String driver = "com.mysql.jdbc.Driver";
5: Class.forName("Driver").newInstance();
6: Connection con=null;
7: ResultSet rst=null;
8: Statement stmt=null;

Answer 1

This is incorrect:

Class.forName("Driver").newInstance();

That's trying to find a class called Driver in the default package.

You potentially want:

Class.forName(driver).newInstance();

... but even that shouldn't be required:

• Just using Class.forName() should initialize the class, which would then register itself with DriverManager

• You don't need to use Class.forName anyway now, if you're working with a fairly modern JRE. From the docs for DriverManager :

  Applications no longer need to explictly load JDBC drivers using Class.forName(). Existing programs which currently load JDBC drivers using Class.forName() will continue to work without modification.

Note that as a matter of style, there's no point in declaring variables and giving them an initial value of null , only to assign a new value immediately. Just use:

Connection con = DriverManager.getConnection(...);
Statement stmt = con.createStatement();
// ...