我从另一个调用此代码的jsp代码中获取datetime1，datetime2，moteid作为输入。这工作正常，脚本 1.sh 工作正常。当我运行此代码时，它显示HTTP状态500错误
<%@page import="java.io.BufferedReader"%>
<%@page import="java.io.InputStreamReader"%>
<%@page import="java.io.File"%>
<%@page import="java.util.Map"%>
<%@page import="com.sixpanview.fileReader"%>
<%@page import="java.util.Calendar"%>
<%@page import="java.text.SimpleDateFormat"%>
<%@page import="java.text.DateFormat"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<%
String id = request.getParameter("moteid");
String[] temp = id.split(":");
String moteid = temp[0];
String datetime1 = temp[1];
String datetime2 = temp[2];
String moteId = temp[3];
String sh = "sh";
String rep = "/root/NetBeansProjects/JavaApplication/web/1.sh";
String cpid = """ + moteid + """;
String mm = datetime1;
String nn = datetime2;
String kk = moteId;
String[] cmdarr = new String[]{sh, rep, moteid, mm, nn, kk};
File file=new File("/root/NetBeansProjects/JavaApplication/web");
ProcessBuilder pb = new ProcessBuilder(cmdarr);
pb.directory(file);
Process p = pb.start();
p.waitFor();
%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<iframe src="report.pdf" width="100%" height="700px"/>
</body>
</html>
它的显示
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 /pdf1jsp.jsp at line 23
20: <head>
21: <%
22: String id = request.getParameter("moteid");
23: String[] temp = id.split(":");
24: String moteid = temp[0];
25: String datetime1 = temp[1];
26: String datetime2 = temp[2];
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:521)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
java.lang.NullPointerException
org.apache.jsp.pdf1jsp_jsp._jspService(pdf1jsp_jsp.java:80)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.35 logs.
22： String id = request.getParameter（"moteid"）;
这里的 id 是空的，这就是在 23 行上抛出 NPE 的原因：
字符串[] temp = id.split（"："）;