java web 中的乱码解决笔记

   by rc

1.-------------------------------
jsp页面乱码
 确保保存的文件内容为UTF-8编码格式
 解决：<%@ pageEncoding="utf-8" %>
2.-------------------------------
调用servlet页面显示乱码
 使用response对内容输出之前，
 设定内容的编码为utf-8
 解决：执行response.setContentType("text/html;charset=utf-8");
3.-------------------------------
post提交表单传递参数乱码
 jsp、html或 servlet的表单元素提交参数给对应的jsp页面或servlet，jsp页面或servlet接收的中文参数值乱码
 在接收参数之前设定接受参数的内容使用utf-8编码
 解决：1.request.setCharaterEncoding("utf-8");
  2.使用过滤器，接收参数之前，设定传递参数的内容编码为utf-8（代码附于文后）
4.-------------------------------
get方式传递参数乱码（表单post、链接方式）
 server.xml中修改<Connetctor port="8080" protocol="HTTP/1.1" maxThreads="150" connectctionTimeout="20000"
redirectPort="8443"/>添加 URIEncoding="UTF-8"
 解决：<Connetctor port="8080" protocol="HTTP/1.1" maxThreads="150" connectctionTimeout="20000" redirectPort="8443"
URIEncoding="UTF-8"/>
 
 

---代码---------web.xml----------------
 <filter>
 <filter-name>CharacterEncodingFilter</filter-name>
 <filter-class>filter.CharacterEncodingFilter</filter-class> 
 <init-param>
 <param-name>encoding</param-name>
 <param-value>UTF-8</param-value>
 </init-param>
 </filter>
 
 
 <filter-mapping>
 <filter-name>CharacterEncodingFilter</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>
 --------filter.CharacterEncodingFilter-------
package 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;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
public class CharacterEncodingFilter implements Filter {
    // ----------------------------------------------------- Instance Variables

    /**
     * The default character encoding to set for requests that pass through
     * this filter.
     */
    protected String encoding = null;

    /**
     * The filter configuration object we are associated with.  If this value
     * is null, this filter instance is not currently configured.
     */
    protected FilterConfig filterConfig = null;

    /**
     * Should a character encoding specified by the client be ignored?
     */
    protected boolean ignore = true;

    // --------------------------------------------------------- Public Methods

    /**
     * Take this filter out of service.
     */
    public void destroy() {
        this.encoding = null;
        this.filterConfig = null;
    }

    /**
     * Select and set (if specified) the character encoding to be used to
     * interpret request parameters for this request.
     *
     * @param request The servlet request we are processing
     * @param result The servlet response we are creating
     * @param chain The filter chain we are processing
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain)
 throws IOException, ServletException {
        // Conditionally select and set the character encoding to be used
        if (ignore || (request.getCharacterEncoding() == null)) {
            String encoding = selectEncoding(request);
            if (encoding != null)
                request.setCharacterEncoding(encoding);
        }
 // Pass control on to the next filter
        chain.doFilter(request, response);
    }

    /**
     * Place this filter into service.
     *
     * @param filterConfig The filter configuration object
     */
    public void init(FilterConfig filterConfig) throws ServletException {
 this.filterConfig = filterConfig;
        this.encoding = filterConfig.getInitParameter("encoding");
        String value = filterConfig.getInitParameter("ignore");
        if (value == null)
            this.ignore = true;
        else if (value.equalsIgnoreCase("true"))
            this.ignore = true;
        else if (value.equalsIgnoreCase("yes"))
            this.ignore = true;
        else
            this.ignore = false;
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Select an appropriate character encoding to be used, based on the
     * characteristics of the current request and/or filter initialization
     * parameters.  If no character encoding should be set, return
     * <code>null</code>.
     * <p>
     * The default implementation unconditionally returns the value configured
     * by the <strong>encoding</strong> initialization parameter for this
     * filter.
     *
     * @param request The servlet request we are processing
     */
    protected String selectEncoding(ServletRequest request) {
        return (this.encoding);
    }
}