我使用 tomcat server 7 和 Mysql 在 jelastic 上部署了我的 jsp Web 应用程序。我的代码在我的本地服务器上运行良好，但是在我将它部署到 jelastic 上之后，它给出了以下错误：
org.apache.jasper.JasperException：在第 11 行处理 JSP 页面 /loginService.jsp 时发生异常
8：字符串错误=空；9: String sql = "SELECT * FROM login_details WHERE user_id='"+user_id+"'"; 10:11:ResultSet 结果 = statement.executeQuery(sql); 12: if(result.next()){ 13: if(result.getString("password").contentEquals(password)){ 14: session.setAttribute("user_session_id", user_id);
堆栈跟踪：org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470) org.apache.jasper.servlet.JspServlet.serviceJspFile( JspServlet.java:390) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 根本原因
java.lang.NullPointerException org.apache.jsp.loginService_jsp._jspService(loginService_jsp.java:91) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet .java:728) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) org.apache.jasper.servlet.JspServlet .service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:728)