我在使用以下 JSP 代码创建表时遇到问题。该错误与我的代码的第 17 行有关。我已经包含了我得到的错误以及我的代码。任何帮助深表感谢！
我的代码
<%@ page import="java.sql.*" %>
<%
String url = "jdbc:odbc:productDSN";
String username="";
String password="";
Connection conn=null;
String classpath = "sun.jdbc.odbc.JdbcOdbcDriver";
try{
Class.forName(classpath);
conn = DriverManager.getConnection(url,username,password);
}catch(Exception exc){
out.println(exc.toString());
}
%>
<%
Statement stm= conn.createStatement();
String query1, query2;
query1="CREATE TABLE product(id char(3) PRIMARY KEY,"+
"name varchar(15),model varchar(5), price float,"+
"manufacturerID integer)";
query2="CREATE TABLE manufacturer("+
"manufacturerID integer PRIMARY KEY,"+
"name varchar(15),address varchar(20), city varchar(20),"+
"state varchar(15), zipCode char(5), phone varchar(15))";
try{
stm.executeUpdate(query1);
stm.executeUpdate(query2);
out.println("Two tables were successfully created.");
}catch(Exception exc){
out.println("These tables exist already.");
}
stm.close();
conn.close();
%>
错误
HTTP Status 500 -
type Exception report
message
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 /example1.jsp at line 17
14:
15: %>
16: <%
17: Statement stm= conn.createStatement();
18: String query1, query2;
19: query1="CREATE TABLE product(id char(3) PRIMARY KEY,"+
20: "name varchar(15),model varchar(5), price float,"+
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:567)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:471)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
root cause
java.lang.NullPointerException
org.apache.jsp.example1_jsp._jspService(example1_jsp.java:82)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.21 logs.
Apache Tomcat/7.0.21