java - How to make a dynamic query for MySQL -

i used spring mvc, how can made dynamic query mysql? have in controller that: public string getnewsbydateandauthor(model model, httpservletrequest request) {}

how can used parameters url request.getparametermap(), , map <string, list<string>> create dynamic query that?

for example, if have 3 parameters want generate 1 query that:

select * news parameter = in(val1, val2...) , parameter2 = in(val1, val2...) , parameter3 = in(val1, val2...) 

or have 1 parameter;

select * news parameter = in(val1, val2...)

if know please show me how can that.

i want code that:

public string getquery(map<string,list<string>> parameters){         list<string> author = new arraylist<>();         list<string> startdate = new arraylist<>();         list<string> enddate = new arraylist<>();         list<string> categories = new arraylist<>();         list<string> = new arraylist<>();         list<string> soureid = new arraylist<>();          if (!parameters.get("author").isempty())             (int = 0; < parameters.get("author").size(); i++) {                 author.add(parameters.get("author").get(i));             }          if (!parameters.get("startdate").isempty())             (int = 0; < parameters.get("startdate").size(); i++) {                 startdate.add(parameters.get("startdate").get(i));             }          if (!parameters.get("enddate").isempty())             (int = 0; < parameters.get("enddate").size(); i++) {                 enddate.add(parameters.get("enddate").get(i));             }          if (!parameters.get("categories").isempty())             (int = 0; < parameters.get("categories").size(); i++) {                 categories.add(parameters.get("categories").get(i));             }          if (!parameters.get("about").isempty())             (int = 0; < parameters.get("about").size(); i++) {                 about.add(parameters.get("about").get(i));             }          if (!parameters.get("soureid").isempty())             (int = 0; < parameters.get("soureid").size(); i++) {                 soureid.add(parameters.get("soureid").get(i));             }          stringbuilder querybuilder = new stringbuilder();         querybuilder.append("select * news where");          if (!author.isempty()) {             string authors = author.tostring();             authors.replace(" ", " , ");             querybuilder.append(" author = in ( " + authors + " ) and");         }         if (!startdate.isempty()) {             string startdates = startdate.tostring();             startdates.replace(" ", " , ");             querybuilder.append(" author = in ( " + startdates + " ) and");         }         if (!enddate.isempty()) {             string enddates = enddate.tostring();             enddates.replace(" ", " , ");             querybuilder.append(" author = in ( " + enddates + " ) and");         }         if (!categories.isempty()) {             string categoriesr = categories.tostring();             categoriesr.replace(" ", " , ");             querybuilder.append(" author = in ( " + categoriesr + " ) and");         }         if (!about.isempty()) {             string abouts = about.tostring();             abouts.replace(" ", " , ");             querybuilder.append(" author = in ( " + abouts + " ) and");         }         if (!soureid.isempty()) {             string sourceids = soureid.tostring();             sourceids.replace(" ", " , ");             querybuilder.append(" author = in ( " + sourceids + " ) and");         }          querybuilder.delete(querybuilder.length() - 3, querybuilder.length());          string query = querybuilder.tostring();          return query; } 

you don't want method that, don't want use string concats create dynamic query. want use criteria api that.

something following

criteriabuilder cb = em.getcriteriabuilder(); criteriaquery<news> cq = cb.createquery(news.class); root<news> news = cq.from(news.class);  if (!parameters.get("author").isempty()) {     cq.where(cb.in(news.get("author"), parameters.get("author")); }  typedquery<news> query = em.createquery(cq); return query.getresultlist(); 

as have multiple results first want create list of predicates , apply them using cq.where(cb.and(predicates.toarray(new predicate[predicates.size()]);.

criteriabuilder cb = em.getcriteriabuilder(); criteriaquery<news> cq = cb.createquery(news.class); root<news> news = cq.from(news.class); list<predicate> predicates = new arraylist<predicate>();  if (!parameters.get("author").isempty()) {     predicates.add(cb.in(news.get("author"), parameters.get("author"))); }  // other params here.  cq.where(cb.and(predicates.toarray(new predicate[predicates.size()])); typedquery<news> query = em.createquery(cq); return query.getresultlist();