过滤器问题，小弟菜鸟 - J2EE论坛 - JAVA论坛

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过滤器问题，小弟菜鸟

我想做一个HTML页面里面有一个文本框和按钮，然后单击按钮把值传到servlet里输出。
我想通过过滤器实现，如果文本框里的值为空则回到html页面里，否则去servlet里。如何实现？只要想看过滤器如何取文本框的值

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第 2 楼

得分:0

request.getParameter("textname");

win32汇编
病毒加密
目前兴趣所在

第 3 楼

得分:0

不行呀
System.out.println(request.getParameter("textname"));
结果是null

第 4 楼

得分:0

没有就是空啊

win32汇编
病毒加密
目前兴趣所在

第 5 楼

得分:0

有

第 6 楼

得分:0

HTML代码
<html>
<body>
<form name="form1" action="\WebModule1\servlet1" method="POST">
<table>
<tr>
<td><input type="text" name="name"></td>
<td><input type="submit" name="submit"></td>
</tr>
</table>
</form>
</body>
</html>

***********************************************************
servlet
package eww;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class Servlet1 extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=GBK";

//Initialize global variables
public void init() throws ServletException {
}

//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
response.setContentType(CONTENT_TYPE);
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>Servlet1</title></head>");
out.println("<body bgcolor=\"#ffffff\">");
out.println(request.getParameter("name"));
out.println("</body>");
out.println("</html>");
out.close();
}

//Process the HTTP Post request
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
doGet(request, response);
}

//Clean up resources
public void destroy() {
}
}
*************************************************
过滤器
package eww;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class Filter1 extends HttpServlet implements Filter {
private FilterConfig filterConfig;
//Handle the passed-in FilterConfig
public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
}

//Process the request/response pair
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain filterChain) {
System.out.println(request.getParameter("name"));
try {
filterChain.doFilter(request, response);
} catch (ServletException sx) {
filterConfig.getServletContext().log(sx.getMessage());
} catch (IOException iox) {
filterConfig.getServletContext().log(iox.getMessage());
}
}

//Clean up resources
public void destroy() {
}
}

第 7 楼

得分:0

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4">
<display-name>WebModule1</display-name>
<filter>
<filter-name>filter1</filter-name>
<filter-class>eww.Filter1</filter-class>
</filter>
<filter-mapping>
<filter-name>filter1</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>servlet1</servlet-name>
<servlet-class>eww.Servlet1</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>servlet1</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>
<servlet>
<description>Added by JBuilder to compile JSPs with debug info</description>
<servlet-name>debugjsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
<init-param>
<param-name>classdebuginfo</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>debugjsp</servlet-name>
<url-pattern>*.jsp</url-pattern>
</servlet-mapping>
</web-app>