javascript - 如何将参数从ajax发送到servlet-6ren

javascript - 如何将参数从ajax发送到servlet

转载作者：行者123 更新时间：2023-11-30 12:36:28

我正在尝试使用 servlet 和 ajax/javascript 添加 2 个数字。我收到 java.lang.NumberFormatException: 并且值为空。我能知道如何将参数从 ajax 传递到 servlet 吗？

SumWithAjaxServlet.java

public class SumWithAjaxServlet extends HttpServlet  {
     protected void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException
        {
            PrintWriter out = response.getWriter();

            System.out.println("n1 : "+request.getParameter("n1"));
            System.out.println("n2 : "+request.getParameter("n2"));

            int num1 = Integer.parseInt(request.getParameter("n1"));
            int num2 = Integer.parseInt(request.getParameter("n2"));
            out.println(num1+num2+"");
        }
}

index.jsp

<script type="text/javascript">
  function calc() 
{ 
    var xmlHttp = new XMLHttpRequest(); 
    var value1 = document.getElementById("n1").value; 
    var value2 = document.getElementById("n2").value; 

    xmlHttp.open("POST", "SumWithAjaxServlet", true); 
    xmlHttp.send(value1 + "," + value2); 

    var result = document.getElementById("result"); 
    result.innerHTML = xmlHttp.responseText; 
}
</script> 
<body>
<form id='calcForm'>
        <table border="3">
            <tr>
                <td>Enter 1st number :</td>
                <td><input type="text" name="n1" id="n1"></td>
            </tr>
            <tr>
                <td>Enter 2nd number :</td>
                <td><input type="text" name="n2" id="n2"></td>
            </tr>
            <tr>
                <td>Result :</td>
                <td><input type="text" value="" id="result"></td>
            </tr>
            <tr>
                <td>&nbsp;</td>
                <td><input type="button" id="calculate" value="calculate"
                    onclick="calc()" /></td>
            </tr>
        </table>
    </form>
</body>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app>

    <servlet>
        <servlet-name>SumWithAjaxServlet</servlet-name>
        <servlet-class>SumWithAjaxServlet</servlet-class>
    </servlet>

    <servlet-mapping>
            <servlet-name>SumWithAjaxServlet</servlet-name>
            <url-pattern>/SumWithAjaxServlet</url-pattern>
    </servlet-mapping>

   <welcome-file-list>  
        <welcome-file>index.jsp</welcome-file>  
   </welcome-file-list> 

</web-app>