老师，请教一下，我获取的 servletConfig对象是倒序的，帮忙看看哪里的问题？
Java源码：
package com.gdyj.demo;
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.*;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
@WebServlet(name = "helloServlet", value = "/hello-servlet")
public class HelloServlet extends HttpServlet {
private String message;
/* public void init() {
message = "Hello World!";
}*/
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
// getRequestInfo(request, response);
// getRequestAllKeys(request, response);
// this.getServletInfomation(request, response);
// this.getWebInformation(request, response);
this.getServletConfigInformation(request,response);
}
void getServletConfigInformation(HttpServletRequest request, HttpServletResponse response) throws IOException {
ServletConfig servletConfig = this.getServletConfig();
Enumeration<String> initParamNames = servletConfig.getInitParameterNames();
/* List<String> list = new ArrayList<>();
while(initParamNames.hasMoreElements()) {
list.add(initParamNames.nextElement());
}*/
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.0 Transitional//EN'>");
out.println("<html><HEAD><TITLE>jacymin</TITLE></HEAD><body>");
/* out.println("list: " + list + "<br/>");
out.println("<br/>");*/
while(initParamNames.hasMoreElements()) {
String str = initParamNames.nextElement();
out.println("key: " + str);
out.println(", value: " + servletConfig.getInitParameter(str) + "<br/>");
}
out.println("<br/>");
out.println("<br/>");
out.println("<br/>");
out.println("end!!!<br/>");
out.println("</body></html>");
out.flush();
out.close();
}
}
web.xml：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<context-param>
<param-name>key1</param-name>
<param-value>value01</param-value>
</context-param>
<context-param>
<param-name>key2</param-name>
<param-value>value02</param-value>
</context-param>
<servlet>
<servlet-name>demoServlet</servlet-name>
<servlet-class>com.gdyj.demo.HelloServlet</servlet-class>
<init-param>
<param-name>key001</param-name>
<param-value>value001</param-value>
</init-param>
<init-param>
<param-name>key002</param-name>
<param-value>value002</param-value>
</init-param>
<init-param>
<param-name>key003</param-name>
<param-value>value003</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>demoServlet</servlet-name>
<url-pattern>/demo.do</url-pattern>
</servlet-mapping>
</web-app>
搜狗浏览器输出结果：
换了 Chrome 浏览器，也是一样的：
老师，我在更新用户的时候，提交之后就给我报500异常，是哪里有问题呀
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