Java Web 怎样修改request的参数值

用过滤器就可以实现，现在web.xml文件中配置好过滤器，自定义个一个过滤器，实现Filter接口，在doFilter中实现自己的过滤逻辑，我这里有个设置所有请求中的字符编码，你可以参考一下：

Java code

web.xml配置如下：


        UrlFilter

        
            com.wgh.common.SetCharacterEncodingFilter
        

        
            defaultEncoding
            GBK
        
    

    

        UrlFilter

        /*
    
 
SetCharacterEncodingFilter过滤器类：
 
package com.wgh.common;
 
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
 
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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
 
public class SetCharacterEncodingFilter implements Filter {
 
 
    
    private static String log = "ksURL_log";
    private static String web_xml_url;
 
    
    protected static String defaultEncoding = null;
    protected FilterConfig filterConfig = null;
    protected boolean ignore = true;
    
    public void destroy() {
        this.defaultEncoding = null;
        this.filterConfig = null;
        this.web_xml_url = null;
 
    }
 
 
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain) throws IOException, ServletException {
        if (ignore || (request.getCharacterEncoding() == null)) {
            String defaultEncoding = selectEncoding(request);
             
            HttpServletRequest req = (HttpServletRequest) request;
            if (defaultEncoding != null){
                String uri = req.getRequestURI();
                String url_suffix = uri.substring(uri.lastIndexOf("/")+1);
                 
                    request.setCharacterEncoding(defaultEncoding);
 
            } 
        }
    }
 
    public void init(FilterConfig filterConfig) throws ServletException {
 
        this.filterConfig = filterConfig;
        this.defaultEncoding = filterConfig.getInitParameter("defaultEncoding");
        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.defaultEncoding);
    }
     
}