我在 jps 下面有一個帶有源和目標下拉列表的代碼以及一個將調用 servlet 的按鈕“執行”。服務員將根據選定的值執行一些操作。JSP代碼：<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title/> </head> <form action="MySourceEnv" method="POST"> <select name="SourceEnv" > <option>10.100.10.11</option> <option>10.100.10.12</option> </select> </form> <form action="MyDestEnv" method="POST"> <select name="DestEnv" > <option>10.100.10.11</option> <option>10.100.10.12</option> </select> </form> <body> <button onclick="location.href = 'http://localhost:7500/Project_1/JavaServlet';" id="RedirectButton" > Execute</button> </body></html> 服務程序代碼：import java.io.*;import javax.servlet.*;import javax.servlet.http.*;public class JavaServletClass extends HttpServlet { public void init() throws ServletException { } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String SourceEnvParam = request.getParameter("SourceEnv"); out.println("<h1>" + SourceEnvParam + "</h1>"); LogicMethod(SourceEnvParam); } private void LogicMethod(String SourceEnvParam) throws IOException { // Some logic here } public void destroy() { }}當單擊執行按鈕并調用 servlet 時，我將request.getParameter("SourceEnv") 的值設為 Null。我在這里做什么錯了？
從 JSP 調用 servlet 時 request.getParameter 中的空值
慕的地8271018
2021-08-13 16:15:21