Java获取完整URL

/**
     * 格式化中文字符，防止出现乱码
     * @param str
     * @return
     */
    public  String codeToString(String str) {
        String strString = str;
        try {
            byte tempB[] = strString.getBytes("ISO-8859-1");
            strString = new String(tempB);
            return strString;
        } catch (Exception e) {
            return strString;
        }
    }
    
    /** *//**
     * 获取完整的Url
     * @param request
     * @return
     * @throws Exception
     */
    public String getBackUrl(javax.servlet.http.HttpServletRequest request) throws Exception {
        String strBackUrl = "";    
        try {
        strBackUrl = "http://" + request.getServerName() + ":" + request.getServerPort() + request.getContextPath() + request.getServletPath() + "?" + this.codeToString(request.getQueryString());    
        strBackUrl = java.net.URLEncoder.encode(strBackUrl,"gbk");
        } catch(Exception e) {
            throw e;
        }
        return strBackUrl;
    }