中文显示1-编码过滤器

在做java开发时，我们会经常碰到中文显示出错的问题，解决方法一般是设置encoding，过滤器，（unicode码）资源文件等等，好用的还是过滤器。

 

过滤器的实现代码在网络上可以找到不少，但自己备份几个还是不错的。

 

• 过滤器1

 

/*	
* 
* TALENTBASE 3.0 Copyright 2005 Neusoft, Co.ltd . 
* All rights reserved.
*			 
* Package:  com.neusoft.talentbase.framework.filter
* FileName: CharsetEncodingFilter.java
* by zhangzhh
* 
* For
*
* version: 1.0
*
* Created on 2005-3-22
* Last Modified: 
* 
* History:
* 
* 
*/

package com.cvicse.inforstudio.weblogs.util;

/**
 * 
 *  @author zhangzhh
 *  @version 1.0
 *  </pre>
 *  Created on :2005-3-22 17:02:47
 *  LastModified:
 *  History:
 *  </pre>
 */
import javax.servlet.*;
import java.io.IOException;

public class CharsetEncodingFilter implements Filter {
    private String defaultEncode = "UTF-8";

    public void init(FilterConfig config) throws ServletException {
        if(config.getInitParameter("charset")!=null){
            defaultEncode=config.getInitParameter("charset");
        }
    }

    public void destroy() {
    }

    public void doFilter(ServletRequest request, 
    					 ServletResponse response,
    					 FilterChain chain) 
    		throws IOException, ServletException {
        ServletRequest srequest=request;
        srequest.setCharacterEncoding(defaultEncode);
        chain.doFilter(srequest,response);
    }
}

• 过滤器2

 

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

public class SetCharacterEncodingFilter 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) {
        try {
            request.setCharacterEncoding("GBK");
            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() {
    }
}

• 过滤器3

 

package test;

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;
import javax.servlet.UnavailableException;

/**
* @author Administrator
*
* TODO 要更改此生成的类型注释的模板，请转至 窗口 － 首选项 － Java － 代码样式 － 代码模板
*/
public class SetCharacterEncodingFilter implements Filter {
protected String encoding = null;
protected FilterConfig filterConfig = null;
protected boolean ignore = true;

public void destroy() {
   this.encoding = null;
   this.filterConfig = null;
}

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);

}

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 String selectEncoding(ServletRequest request) {
   return (this.encoding);
}

}

等一下，这还没完，还要在web.xml里面配置一下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
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">
<display-name>myweb</display-name>

<filter>
   <filter-name>Set Character Encoding</filter-name>
   <filter-class>test.SetCharacterEncodingFilter</filter-class>
   <init-param>
    <param-name>encoding</param-name>
    <param-value>UTF-8</param-value>
   </init-param>
</filter>

<filter-mapping>
   <filter-name>Set Character Encoding</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>

<welcome-file-list>
   <welcome-file>index.html</welcome-file>
   <welcome-file>index.htm</welcome-file>
   <welcome-file>index.jsp</welcome-file>
   <welcome-file>default.html</welcome-file>
   <welcome-file>default.htm</welcome-file>
   <welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>

。。。。。。。。。。。。。。。。。。。。。。。。。。。

 

类似的东西不少，前两个用过，不错；后面的从视觉上看挺漂亮，推荐！

=================================================================================

 

应用中总是发现各种各样的乱码问题，简单分类一下：

1.Java文件和JSP文件编码时产生乱码

即：在Java和jsp文件中包含中文字符，而Java或jsp在编译的时候是采用字节流的（其他编码），产生编码不一致，出现乱码。解决方法：

java文件：文件属性中的Encoding编码设置为GBK、GB2312或UTF-8

JSP文件：在文件头设置<%@ page contentType="text/html;charset=GBK"%>

 

2.和其他应用交互时产生乱码，通常会在Request中的URI产生乱码。

原因是很多程式是基于字节流的，而Java程序是基于字符流。解决办法：

Tomcat：修改conf/server.xml，找到

<!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
    <Connector 
    	acceptCount="100" 
    	connectionTimeout="20000" 
    	disableUploadTimeout="true" 
    	enableLookups="false" 
    	maxHttpHeaderSize="8192" 
    	maxSpareThreads="75" 
    	maxThreads="150" 
    	minSpareThreads="25" 
    	port="8080" 
    	redirectPort="8443" URIEncoding="GBK"  />

 在最后面加上URIEncoding="GBK".

 

另一种就是在HttpServelet中doGet方法中设置contentype=GBK，这样在处理请求前编码格式就被处理了。例：

public class MyHttpServlet extends HttpServlet {
  public void doGet(HttpServletRequest request,HttpServletResponse response)
   throws ServletException, IOException {
      response.setContentType("text/html; charset=GBK");
      // Do Other Things
  }  
}