新手有关问题：servlet中设定的值怎么在JSP中显示
日期：2014-05-18 浏览次数：20596 次
新手问题：servlet中设定的值如何在JSP中显示
小弟正在学习JSP，想在java中设定一个值，在jsp画面中显示出来，代码如下，又明白的麻烦请指点一下。
--index.jsp
<%@ page contentType= "text/html; charset=UTF-8 " %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN ">
<html>
<head>
<title> CATOFTOM </title>
<meta http-equiv= "Content-Type " content= "text/html; charset=Shift_JIS ">
</head>
<body>
<form action= "index " method= "get ">
<table>
<tr>
<td> number1: </td>
<td> <input type= "text " name= "num1 " size= "20 ">
</td>
<tr>
<td> number2: </td>
<td> <input type= "text " name= "num2 " size= "20 ">
</td>
<tr>
<td> total: </td>
<td> <%=request.getAttribute( "total ") %>
</td>
<td>
</td>
</tr>
<tr>
<td colspan= "2 ">
<input type= "submit " name= "action " value= "add ">
<input type= "submit " name= "action " value= "sub ">
</td>
</tr>
</table>
</form>
</body>
</html>
--index.java
package test;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Index extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setAttribute( "total ", "test ");
RequestDispatcher rd=request.getRequestDispatcher( "/index.jsp ");
rd.forward(request,response);
}
}
------解决方案--------------------
请求的地址应该是Servlet的URL,并且要用GET方法（直接在地址栏中输地址），而不是index.jsp的URL，如果直接请求index.jsp的话，是没有值的。
至于直接在画面上显示 ${total}，应该是不支持EL表达式吧。需要servelet2.4,jsp2.0
------解决方案--------------------
http://cache.baidu.com/c?word=requestdispatcher%2C%B2%CE%CA%FD&url=http%3A//topic%2Ecsdn%2Enet/t/20050713/08/4140590%2Ehtml&p=8a67c54add9d1dfc57ee9e2f5354&user=baidu
小弟正在学习JSP，想在java中设定一个值，在jsp画面中显示出来，代码如下，又明白的麻烦请指点一下。
--index.jsp
<%@ page contentType= "text/html; charset=UTF-8 " %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN ">
<html>
<head>
<title> CATOFTOM </title>
<meta http-equiv= "Content-Type " content= "text/html; charset=Shift_JIS ">
</head>
<body>
<form action= "index " method= "get ">
<table>
<tr>
<td> number1: </td>
<td> <input type= "text " name= "num1 " size= "20 ">
</td>
<tr>
<td> number2: </td>
<td> <input type= "text " name= "num2 " size= "20 ">
</td>
<tr>
<td> total: </td>
<td> <%=request.getAttribute( "total ") %>
</td>
<td>
</td>
</tr>
<tr>
<td colspan= "2 ">
<input type= "submit " name= "action " value= "add ">
<input type= "submit " name= "action " value= "sub ">
</td>
</tr>
</table>
</form>
</body>
</html>
--index.java
package test;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Index extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setAttribute( "total ", "test ");
RequestDispatcher rd=request.getRequestDispatcher( "/index.jsp ");
rd.forward(request,response);
}
}
------解决方案--------------------
请求的地址应该是Servlet的URL,并且要用GET方法（直接在地址栏中输地址），而不是index.jsp的URL，如果直接请求index.jsp的话，是没有值的。
至于直接在画面上显示 ${total}，应该是不支持EL表达式吧。需要servelet2.4,jsp2.0
------解决方案--------------------
http://cache.baidu.com/c?word=requestdispatcher%2C%B2%CE%CA%FD&url=http%3A//topic%2Ecsdn%2Enet/t/20050713/08/4140590%2Ehtml&p=8a67c54add9d1dfc57ee9e2f5354&user=baidu
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