2013-04-03 51 views
0

我正在尝试创建一个将插入通过表单提交的记录的JSP。但是,我试图确保它连接,并使用mySQL select语句来检索数据。我发布了下面的错误。我不知道为什么我得到这个错误。到目前为止,我有这个使用JSP提交表单提交

<%@ page import ="java.sql.*" %> 
<% 
String url = "jdbc:mysql//sql.njit.edu:3306/user"; 
String user = "u"; 
String pass = "p"; 
String classPath = "com.mysql.jdbc.Driver"; 
Connection conn = null; 
Statement stmt = null; 
ResultSet rs = null; 

try{ 
    Class.forName(classPath); 
    conn = DriverManager.getConnection(url, user, pass); 
} catch(Exception e){ 
    e.printStackTrace(); 
} 

stmt = conn.createStatement(); 

String query = "SELECT * FROM Music"; 

try{ 
    rs = stmt.executeQuery(query); 
    while(rs.next()){ 
     out.println(rs.getString("song")); 
    } 
}catch(SQLException e){ 
    e.printStackTrace(); 
} 
finally { 
    try { 
     if (stmt != null) 
      stmt.close(); 
     if (rs != null) 
      rs.close(); 
     if (conn != null) 
      conn.close(); 
    }catch (SQLException e) { 
     e.printStackTrace(); 
    } 
} 
%> 

我收到以下错误

Stacktrace: 
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451) 
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373) 
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:321) 
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:257) 
javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 

root cause 

java.lang.NullPointerException 
org.apache.jsp.insert_jsp._jspService(insert_jsp.java:64) 
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98) 
javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:321) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:257) 
javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 

回答

0

你的JDBC URL格式错误。它应该像

jdbc:mysql//sql.school.edu:3306/user 
+0

我仍然得到错误。 – user1709294

+0

那么,不要在catch中打印堆栈跟踪,而是打印catch块标识符(在获取conn期间sat'失败)并找出失败的位置。这会给你更多的见解。 –