JavaScript

请问这串代码什么意思，看的糊涂

new CommDAO().delete(request,"jiaoxuezichan"); 
   String url = "jiaoxuezichan_list.jsp?1=1"; 
   String sql =  "select * from jiaoxuezichan where 1=1";
    
if(request.getParameter("zichanbianhao")=="" ||request.getParameter("zichanbianhao")==null ){
}else{sql=sql+" and zichanbianhao like '%"+request.getParameter("zichanbianhao")+"%'";}

if(request.getParameter("zichanmingcheng")=="" ||request.getParameter("zichanmingcheng")==null ){
}else{sql=sql+" and zichanmingcheng like '%"+request.getParameter("zichanmingcheng")+"%'";}

if(request.getParameter("zichanleibie")=="" ||request.getParameter("zichanleibie")==null ){
}else{sql=sql+" and zichanleibie like '%"+request.getParameter("zichanleibie")+"%'";}

if(request.getParameter("zhuangtai")=="" ||request.getParameter("zhuangtai")==null ){
}else{sql=sql+" and zhuangtai like '%"+request.getParameter("zhuangtai")+"%'";}

if(request.getParameter("shiyongjiaoshi")=="" ||request.getParameter("shiyongjiaoshi")==null ){
}else{sql=sql+" and shiyongjiaoshi like '%"+request.getParameter("shiyongjiaoshi")+"%'";}
    sql+=" order by id desc";
    ArrayList list = PageManager.getPages(url,15,sql, request); 
    int i=0;
    for(HashMap map:list){ 
    i++;

这些代码都是sql查询，操作数据库的。

这是在js里动态拼接数据库指令的，建议不要使用这种方式，第一，容易暴露数据库结构，第二，很容易被注入攻击

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