JSP程序之前一台电脑可以运行，但是另一台电脑就不行

Question

程序如下

 5.public class DBConBean {

    private static final String URL = "jdbc:mysql://127.0.0.1:3306/bank";
    private static final String USER = "root";
    private static final String PASSWORD = "";

    private static Connection conn = null;
    Statement stat = null;
    PreparedStatement pstat = null;
    ResultSet rs = null;
    int rs_1 = 0;

    public static Connection getConnection() {
        try {
            //加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //获得数据库连接
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return conn;
    }

    public ResultSet query (String sql) {
        try {
            conn = getConnection();
37.         stat = conn.createStatement();
            rs = stat.executeQuery(sql);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return rs;
    }

报错如下
type Exception report

message java.lang.NullPointerException

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

java.lang.NullPointerException
com.zy.dao.DBConBean.query(DBConBean.java:37)
org.apache.jsp.Page_005fuser_jsp._jspService(Page_005fuser_jsp.java:161)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:439)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
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/7.0.65 logs.
求大神解答

Answer 1

断点一下看看conn是不是为空，如果为空就可以往2个方向找错误，1，有没有jdbc的驱动包，2、用户名密码和URL是不是对，你这里可以在本地用数据库的客户端看看能不能脸上，有没有这个数据库。