Filter 字符编码Filter 一

使用字符编码Filter

package com.helloweenvsfei.filter;

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 CharacterEncodingFilter implements Filter {

    private String characterEncoding;
    private boolean enabled;

    @Override
    public void init(FilterConfig config) throws ServletException {

        characterEncoding = config.getInitParameter("characterEncoding");

        enabled = "true".equalsIgnoreCase(characterEncoding.trim())
                || "1".equalsIgnoreCase(characterEncoding.trim());
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        if (enabled || characterEncoding != null) {
            request.setCharacterEncoding(characterEncoding);
            response.setCharacterEncoding(characterEncoding);
        }

        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
        characterEncoding = null;
    }
}

web.xml 配置如下

<filter>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>
            com.helloweenvsfei.filter.CharacterEncodingFilter
        </filter-class>

        <init-param><!-- 编码方式 -->
            <param-name>characterEncoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param><!-- 是否使用编码 -->
            <param-name>enable</param-name>
            <param-value>true</param-value>
        </init-param>
</filter>

<filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
</filter-mapping>

注意：页面编码方式必须一致。另外如果使用GET表单提交。需要修改Tomcat /conf/server.xml 里的URIEncoding 修改代码如下

 <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443"  URIEncoding = "UTF-8"/>

基本所有的javaWeb程序都用该Filter。

附：characteEncoding.jsp验证编码器

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"%>
 2 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 3 <html>
 4 <head>
 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 6 <title>Insert title here</title>
 7 <style>
 8 body, input, textarea {
 9     font-size: 12px; 
10 }
11 textarea {
12      400px; 
13     height: 50px; 
14 }
15 </style>
16 </head>
17 <body>
18 <pre>
19 <b>您输入了</b>：
20 ${ param.text }
21 </pre>
22 <form action="${ param.request.requestURL }" method="post"><textarea
23     name="text">${ param.text }</textarea> <br />
24 <input type="submit"></form>
25 
26 </body>
27 </html>