一样写法
${if(len(开始日期)=0,""," and 开始日期>='"+开始日期+"'")}
${if(len(结束日期)=0,""," and 结束日期<='"+结束日期+"'")}
${if(len(开始日期参数)=0,""," and 登记日期>='"+开始日期参数+"'")}
${if(len(结束日期参数)=0,""," and 登记日期<='"+结束日期参数+"'")}