多个条件查询 写法

　　String where = "where 1=1";
　　if(PERSON != null && !"".equals(PERSON)&& PERSON!=""){
where += " and p.PERSON like '%" + PERSON + "%'";
}
if(PRO_NAME != null &&!"".equals(PRO_NAME)&&PRO_NAME!=""){
where += " and p.PRO_NAME like '%" + PRO_NAME + "%'";
}
if(DOC_NAME != null && !"".equals(DOC_NAME) && DOC_NAME!=""){
where += " and l.DOC_NAME like '%" + DOC_NAME + "%'";
}
　  sql="Select p.person,p.pro_name,l.doc_name,p.borrow_deadline,l.is_borrow,l.is_returned From loan_doc l Left Join pro_comp_info_borrow_reg p On p.guid=l.pro_guid "+where+"";
　　//　　然后去执行sql语句