java - 使用 servlet 显示系统属性

Question

我正在使用 servlet 作为新手，我一直在尝试获取桌面应用程序，并尝试看看当我使用 servlet 时它们如何出现，使用 system.getproperty 方法，如果我点击提交按钮，我会收到一条空白消息。

这是我的jsp代码。

<form action="checkservlet" method="get">
<input type="submit" value="submit"/><br/>
</form>

这是我的 servlet 代码

package com.check.pack;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * Servlet implementation class checkservlet
 */
@WebServlet("/checkservlet")
public class checkservlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public checkservlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html");
        PrintWriter write = response.getWriter();
        Mulizwa Mcheck = new Mulizwa();
    }

}

这是我的类(class)代码

package com.check.pack;
import java.util.*;

public class Mulizwa {

     public static void main(String[] args) {
            Properties prop = System.getProperties();
            Set<Object> keySet = prop.keySet();
            for(Object obj : keySet){
                System.out.println("System Property: {"+obj.toString()+","+System.getProperty(obj.toString())+"}");
            }
        }
}

我不是专家，但我来这里是为了学习，如果我点击提交按钮，我对上面的代码有何期望，我需要在浏览器中查看有关系统属性(如操作系统名称、java 版本等)的响应。

Answer 1

首先，您需要在 Mulizwa 类中编写一个函数，该函数可能返回系统属性的字符串，而不是在标准输出上打印属性的 main 方法，如下所示

 public String getPropertyString (){
            Properties prop = System.getProperties();

StringBuilder propertyString = new StringBuilder();
            Set<Object> keySet = prop.keySet();
            for(Object obj : keySet){
                propertyString.append("System Property: {"+obj.toString()+","+System.getProperty(obj.toString())+"}");
            }

return propertyString.toString();
}

然后在 servlet 的 doPost 方法中，

PrintWriter write = response.getWriter();
        Mulizwa mCheck = new Mulizwa();
write.write(mCheck.getPropertyString());