过滤器

Question

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <init-param>
      <param-name>config</param-name>
      <param-value>/WEB-INF/struts-config.xml</param-value>
    </init-param>
    <init-param>
      <param-name>debug</param-name>
      <param-value>3</param-value>
    </init-param>
    <init-param>
      <param-name>detail</param-name>
      <param-value>3</param-value>
    </init-param>
    <load-on-startup>0</load-on-startup>
  </servlet>
<!-- 重新部署filter -->
<filter>
<filter-name>MyFilter</filter-name>
<filter-class>com.ms.filter.MyFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
<!-- 完成对过滤器的映射 -->
<filter-mapping>
<filter-name>MyFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</filter>
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
 
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>
package com.ms.filter;import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class MyFilter extends HttpServlet implements Filter {
private String encoding;
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
// TODO Auto-generated method stub
arg0.setCharacterEncoding(encoding);
arg2.doFilter(arg0, arg1);
} public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
 encoding=arg0.getInitParameter("encoding");
}}
为何还是不能过滤乱码

Answer 1

arg0.setCharacterEncoding(encoding);
这一句改成
arg0.setCharacterEncoding("UTF-8");//一般建议改成把arg0改成request这样的方式
arg1.setCharacterEncoding("UTF-8");
你给人家一个空指针，你启动的时候没报异常？

Answer 2

你的表单是"post"方式提交的么?
request.setCharacterEncoding("UTF-8");这种方式只能处理"post"方式提交的乱码

Answer 3

你这是啥请求啊？ post? get? 你这种只能处理 post请求有效。

Answer 4

是啊！那要咋整？数据库是sql2005

Answer 5

过滤器为什么要extends HttpServlet？
看看你的arg0.getInitParameter("encoding")
得到配置参数utf-8了没？

Answer 6

lz你把  <load-on-startup>0</load-on-startup>
删掉试试

Answer 7

这个能删吗？这个配置不是让它在tomcat启动的时候载入的吗？

Answer 8

你都没有给FilterConfig 初始化，
在encoding=arg0.getInitParameter("encoding"); 这句上面加一句FilterConfig config=arg0; 
如果没有这句你的arg0怎么能接收到encoding呢