Encoding filter 编码过滤器

1、首先编写过滤器，实际上就是继承了filter接口的一个类，实现其中的init  doChain  和destroy方法

package com.util;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class EncoderFilter implements Filter {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        System.out.println("i defined filter destroy~~~~~~~~~~~~~~~~~~~~~~");
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain arg2) throws IOException, ServletException {
        // TODO Auto-generated method stub
        arg0.setCharacterEncoding("UTF-8");
        System.out.println("the request encoding is " + arg0.getCharacterEncoding());
        System.out.println("enter myself filter~~~~~~~~~~~~~~~~~~~~~~" + new String(arg0.getParameter("men.name").getBytes(), "GBK"));
        arg2.doFilter(arg0, arg1);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
        System.out.println("i defined filter init~~~~~~~~~~~~~~~~~~~~~~");
    }

}

EncoderFilter.java

2、在web.xml文件里面，加入如下代码

  <filter>
          <filter-name>encodeFilter</filter-name>
          <filter-class>com.util.EncoderFilter</filter-class>
  </filter>
  <filter-mapping>
          <filter-name>encodeFilter</filter-name>
          <url-pattern>/*</url-pattern>
  </filter-mapping>

web.xml

切记，此代码应该加在struts2的过滤器前面的位置。

这时候访问传汉字应该是没有问题了，可是~~~还是乱码，解决办法：修改tomcat的server.xml文件

将<Connector port="8080" protocol="HTTP/1.1"                connectionTimeout="20000"                redirectPort="8443" />里添加上后面3个编码的设置

<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443"
useBodyEncodingForURI="true"
IEncoding="utf-8"
URIEncoding="utf-8"
/>

这时候传汉字就正常了！

关于编码，可以使用request.getCharacterEncoding()方法来看请求时采用的是什么编码！