java 异常修改

org.apache.jasper.JasperException: Exception in JSP: /cklogin.jsp:118: <%
9: Class.forName("org.gjt.mm.mysql.Driver"); 
10: String url="jdbc:mysql://localhost:3306/storage?user=root&password=root&useUnicode=true&characterEncoding=GB2312";
11: Connection conn= DriverManager.getConnection(url); 
12: Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
13: request.setCharacterEncoding("gb2312");
14: String username=request.getParameter("username");
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:355)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause javax.servlet.ServletException: com/mysql/jdbc/StringUtils
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:841)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:774)
org.apache.jsp.cklogin_jsp._jspService(cklogin_jsp.java:98)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause java.lang.NoClassDefFoundError: com/mysql/jdbc/StringUtils
com.mysql.jdbc.NonRegisteringDriver.parseURL(NonRegisteringDriver.java:441)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:259)
java.sql.DriverManager.getConnection(DriverManager.java:582)
java.sql.DriverManager.getConnection(DriverManager.java:207)
org.apache.jsp.cklogin_jsp._jspService(cklogin_jsp.java:53)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
怎么处理错误，应该是个小错误，这个是别人给我的一个毕业设计，我想想练一下，希望高手帮一下。