如何从JSP页面调用servlet？

发布于 2024-10-05 21:40:04 字数 2399 浏览 3 评论 0 原文

可能的重复：
从 JSP 文件调用 servlet

我使用以下代码来调用 index.jsp 的 >conn.java（servlet）。有用。

<%@page import= "java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<%@ page import= "aa.conn" %>
<jsp:useBean id= "conne" class= "conn" scope= "session"/>
<jsp:setProperty name= "conne" property= "*"/>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP</title>

    </head>
    <body>
       <link rel="stylesheet" href="rowcolor.css" type="text/css">
      <%

      conne.con(request, response);
     ArrayList newlist=null;
    newlist=(ArrayList)request.getAttribute("data1");
    int noofrows=(Integer)newlist.get(0);
    int q = noofrows / 5;
    if(noofrows%5!=0)
        q+=1;
    out.println("Pages --->>>");
         for (int t = 1; t <= q; t++) {
            out.println("<a href=index.jsp?id=" + t + " name=" + t + "id=" + t + ">");
            out.println("  " + t);
            out.println("</a>");
        }
     conne.disp(request, response);
     conne.dispgraphtab(request, response);
      %>




    </body>
</html>

但是，下面的代码不起作用。我想从 graphcon.jsp 调用 NewServlet。

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<%@ page import= "aa.NewServlet" %>
<jsp:useBean id= "co" class= "NewServlet" scope= "session"/>
<jsp:setProperty name= "co" property= "*"/>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>

    </body>
</html>

这段代码有什么问题？错误是：

exception
javax.servlet.ServletException: java.lang.InstantiationException: NewServlet
root cause 
java.lang.InstantiationException: NewServlet

原文

Possible Duplicate:
Calling a servlet from JSP file

I have used following code to call a conn.java (servlet) from index.jsp. It works.

<%@page import= "java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<%@ page import= "aa.conn" %>
<jsp:useBean id= "conne" class= "conn" scope= "session"/>
<jsp:setProperty name= "conne" property= "*"/>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP</title>

    </head>
    <body>
       <link rel="stylesheet" href="rowcolor.css" type="text/css">
      <%

      conne.con(request, response);
     ArrayList newlist=null;
    newlist=(ArrayList)request.getAttribute("data1");
    int noofrows=(Integer)newlist.get(0);
    int q = noofrows / 5;
    if(noofrows%5!=0)
        q+=1;
    out.println("Pages --->>>");
         for (int t = 1; t <= q; t++) {
            out.println("<a href=index.jsp?id=" + t + " name=" + t + "id=" + t + ">");
            out.println("  " + t);
            out.println("</a>");
        }
     conne.disp(request, response);
     conne.dispgraphtab(request, response);
      %>




    </body>
</html>

But, this following code doesn't work. I want to call NewServlet from graphcon.jsp.

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<%@ page import= "aa.NewServlet" %>
<jsp:useBean id= "co" class= "NewServlet" scope= "session"/>
<jsp:setProperty name= "co" property= "*"/>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>

    </body>
</html>

What is the problem with this code? The error is:

exception
javax.servlet.ServletException: java.lang.InstantiationException: NewServlet
root cause 
java.lang.InstantiationException: NewServlet

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随波逐流 2024-10-12 21:40:04

把你的问题说清楚。首先描述您想要做什么，然后描述您为完成您想要做的事情而遵循的步骤，然后描述您的步骤中出现的问题。我想您想要的是将您的请求重定向到一个 servlet。为此，请使用 sendredirect 函数。

回复收藏 0 原文

折戟 2024-10-12 21:40:04

如果您想从 JSP 文件调用 Servlet，请执行以下操作：

在 JSP 文件中

<html>
    <head></head>
    <body>
        <form  action="/dataBase/DBInit" method="post">    // here call Servlet
            Design
        </form>
        <%       Logic         %>
    </body>
</html>

在 Web.xml 中

<servlet>
    <servlet-name>dbname</servlet-name>
    <servlet-class>com.db.DBInit</servlet-class>     // Servlet Path Define Here
</servlet>
<servlet-mapping>
    <servlet-name>dbname</servlet-name>
    <url-pattern>/DBInit</url-pattern>
</servlet-mapping>

If you want to call Servlet from the JSP file then do this:

In JSP File

<html>
    <head></head>
    <body>
        <form  action="/dataBase/DBInit" method="post">    // here call Servlet
            Design
        </form>
        <%       Logic         %>
    </body>
</html>

In Web.xml

<servlet>
    <servlet-name>dbname</servlet-name>
    <servlet-class>com.db.DBInit</servlet-class>     // Servlet Path Define Here
</servlet>
<servlet-mapping>
    <servlet-name>dbname</servlet-name>
    <url-pattern>/DBInit</url-pattern>
</servlet-mapping>

回复收藏 0 原文

~没有更多了~