Question

我有一个config.properties文件，其中存储了数据库的凭据，但是当我尝试从connection.jsp读取它时，它给了我“NullPointerException”。

我在eclipse中运行以下代码时遇到上述错误 -

config.properties： -

jdbc.url= jdbc:mysql://localhost:3306/mysqldb
jdbc.driver = com.mysql.jdbc.Driver
jdbc.username= root
jdbc.password= root

connection.jsp： -

<%@ page import="java.util.Properties" %>
<%@ page import= "java.sql.* " %> 

<%
 Properties properties=new Properties();    
    properties.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("config.properties"));
    //InputStream in =  getClass().getResourceAsStream("config.properties");    
    String url=properties.getProperty("jdbc.url");
    String driver=properties.getProperty("jdbc.driver");
    String username=properties.getProperty("jdbc.username");
    String password=properties.getProperty("jdbc.password");
    Class.forName("com.mysql.jdbc.Driver");
    Connection con= DriverManager.getConnection(url,username,password); 
%>

emp_id.jsp（从数据库打印数据）： -

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
        pageEncoding="ISO-8859-1"%>
        <%@ page import="java.util.Properties" %>
    <%@page import="java.sql.*" %>
    <%@page import="java.sql.Connection" %>
    <%@ page import="java.io.*" %> 
    <%@ include file= "connection.jsp" %>

    <%
            String query15="select emp_id from employees";
            Statement st15=con.createStatement();
            ResultSet rs15=st15.executeQuery(query15);
            while(rs15.next())
            {
            System.out.print(rs15.getString(1));        
            }

    %>

我收到此错误消息： -

HTTP Status 500 - An exception occurred processing JSP page /connection.jsp at line 8


type Exception report

message An exception occurred processing JSP page /connection.jsp at line 8

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 /connection.jsp at line 8

5: Properties properties=new Properties();
6:  File file = new File("config.properties");
7:  System.out.println(file.getAbsolutePath());
8:  properties.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("config.properties"));
9:  //InputStream in =  getClass().getResourceAsStream("config.properties");
10:     
11:     


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:579)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)


root cause
java.lang.NullPointerException
    java.util.Properties$LineReader.readLine(Properties.java:434)
    java.util.Properties.load0(Properties.java:353)
    java.util.Properties.load(Properties.java:341)
    org.apache.jsp.test_jsp._jspService(test_jsp.java:136)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)


note The full stack trace of the root cause is available in the Apache Tomcat/8.0.44 logs.

我有一个config.properties文件，其中存储了数据库的凭据，但是当我尝试执行它时，给了我“NullPointerException”

0 个答案: