Java多语言编码问题解析(2)

类别:Java 点击:0 评论:0 推荐:

这里是一个具体的例子:

现在因为浏览器对UTF-8的支持,我们可以通过在源文件、请求、响应中都使用unicode编码方式,来轻松达到处理国际化和字符编码问题的目标。
以我们使用的tomcat4.1.2为例,过程如下:

1、编写JSP页面时:在每个JSP页面在页首都要增加一行:

在编辑JSP页面时,一定要确保JSP文件以unicode的方式保存,目前几乎所有的编辑器都有以unicode编码保存或将文件内容转换成unicode的功能。

2、增加一个用来声明request的CharacterEncoding的类SetCharacterEncodingFilter.java;
SetCharacterEncodingFilter的这个类主要的作用就是:把request在从页面刚提交到server端的时候的encoding声明为我们想要的encoding,通过调用request的方法setCharacterEncoding (String encoding) 来改变,这样可以使request的从客户端传过来的时候,按我们在web.xml (在第二点可以讲到) 中配置的encoding来对提交的数据编码。

3、修改web.xml文件,配置一个filter来过滤全部url请求,通过第二步中的类,声明所有url请求的编码类型未UTF-8。
在web.xml文件中加上以下这段:


  Set Character Encoding
  org.kyle.web.sample.SetCharacterEncodingFilter
                       
     

encoding
     

UTF-8
   


   Set Character Encoding
   /*


在上面这段文字中“org.kyle.web.sample.SetCharacterEncodingFilter”指定步骤2中的类的位置,“ UTF-8”指定我们希望声明的request的编码类型,“/*”指定这个filter的适用范围(这里指的是全部url请求)。

同时注意二个问题:
1:servlet的版本必需是支持request.setCharacterEncoding(String encoding)这个方法才行,也就是在serlvert2.3以上。
2:控制面板区域设置的当前代码页属性必需设定为"936 (GBK)",如果是"437(OEM-United States)"它处理文字的时候是8-bit,而中文和日文等是16-bit。所以在显示和处理时它把中文的前8位给截掉,这样就会出现乱码问题。

附:SetCharacterEncodingFilter源文件
package org.kyle.web.sample;
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;
public class SetCharacterEncodingFilter implements Filter
{
    /**
     * 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;

    /**
     * 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
     *                   
     *

encoding
     *

UTF-8
     *
     */
    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;
    }

    /**
     * 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
     * null.
     *


     * The default implementation unconditionally returns the value configured
     * by the encoding initialization parameter for this
     * filter.
     *
     * @param request The servlet request we are processing
     */
    protected String selectEncoding(ServletRequest request)
    {
        return (this.encoding);
    }
}

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