I have a list of object which contain 10000 records i am trying to split that records in each of 10,
But somehow it is not working.. can someone have a look
#Query("select a.applicantid,coalesce(to_char(a.createdon,'yyyy-MM-dd'),to_char(filing_date,'yyyy-MM-dd')) as dt1, \r\n" +
"coalesce(c.companyname,i.InstituteName,(u.firstname||' '||u.lastname),\r\n" +
"u.firstname) ,a.c_denomination,cc.crop_common_name,cs.crop_botanical_name,\r\n" +
"a.id,aps.status,a.cropid, \r\n" +
"(select mv.varietytype from VarietyType mv where mv.id= a.varirtytypeid),\r\n" +
"(select sv.subvarietytype from SubVarietyType sv,VarietyType mvr \r\n" +
" where a.subvarietytypeid = sv.id and mvr.id= sv.varietyid),a.formtype,mcg.crop_group \r\n" +
" from Applications a left join ApplicantRegistration ap on \r\n" +
" a.applicantid = ap.id left join CompanyRegistration c on ap.companyid = c.id \r\n" +
" left join InstitutionRegistration i on ap.institutionid = i.id \r\n" +
" left join Crops cc on a.cropid = cc.id left join CropSpecies cs \r\n" +
" on a.cropspeciesid =cs.id left join InternalUser u on ap.id = u.applicantid \r\n" +
" left join ApplicationStatus aps on a.application_current_status = aps.id "
+ "left join CropGroup mcg on cc.cropgroupid = mcg.id order by a.id desc")
List<Object[]> getapplication_adminview();
List<Object[]> admin_viewapplication=applicationrepository.getapplication_adminview();
int pageNumber = 0;
int size = 10;
Pageable pageable = PageRequest.of(pageNumber, size); // object of pageable
Page<Object> pages = new PageImpl(admin_viewapplication, pageable, admin_viewapplication.size());
List<Object> lpage = pages.getContent(); // here i am getting the lpage size as 10000 but as i enter pageable as of size 10 i am expecting 10 results only
where i am going wrong in this ?
if i am trying to add pagable object to query and run the code i will get the following error:
Cannot create TypedQuery for query with more than one return using requested result type [java.lang.Long]; nested exception is java.lang.IllegalArgumentException: Cannot create TypedQuery for query with more than one return using requested result type [java.lang.Long]
Page just represents one page of data . So page.getContent() only return all data in one page which is specified through constructor when you create this page instance . It has nothing to do with splitting the data in a page.
If you want to split a list , use Lists from Guava is the simplest way to go :
List<List<Object>> splittedList = Lists.partition(list, 10);
If you want to do pagination which split all the data stored in the database into different smaller pages , split it at the database level rather than getting the whole list to the memory to split which will be very inefficient when the entire list is large. See this for how to split it at the database level by declaring Pageable in the query method.
We can use PagedListHolder which can change the list in pages and we can than fetch a page by setting it's page size and page.
PagedListHolder<Object> page = new PagedListHolder(admin_viewapplicationpage);
page.setPageSize(50); // number of items per page
page.setPage(0); // set to first page
int totalPages = page.getPageCount(); // gives the totalpages according to the main list
List<Object> admin_viewapplication = page.getPageList(); // a List which represents the current page which is the sublist
the following tutorial helped me
-> https://www.baeldung.com/spring-data-jpa-query
At this point 4.3. Spring Data JPA Versions Prior to 2.0.4
VERY IMPORTANT to add \ n-- #pageable \ n
Without this I was wrong
Also the pagination setting must be without ordering
PageRequest paginaConf = new PageRequest ((param1 - 1)
, param2);
Finally to convert the Page <Object []>
Page <Object []> list = myQueryofRepo ();
List <XXXModel> lstReturn = myConversor (list.getContent ());
Page <XXXModel> ret = new PageImpl <XXXModel> (lstReturn, pageConf, param2);
Related
I have requirement where I need to get the records based in join of three table with pagination(addition requirement are also there). So I have written a nativeQuery to get the records. Below is the sample query
#Query(value = "SELECT "
+ "a.GROUP_REF_ID as refId "
+ "count(case when c.STAT_CD in :userStatus then (c.grp_user_id) end) as numberOfUsers, "
+ "count(case when b.STAT_CD in :itemStatus then (b.grp_item_id) end) as numberOfItems "
+ "from grp a left join grp_item b on a.grp_id=b.grp_id left join grp_user c on a.grp_id=c.grp_id "
+ "where a.stat_cd in :status and a.co_id in :cids "
+ "group by a.GROUP_REF_ID,a.grp_nam,a.GRP_DESC,a.co_id,a.co_nam,a.CRTE_BY, "
+ "a.CRTE_DT,a.UPDT_BY,a.UPDT_DT ", countQuery = "select count(*) from grp where stat_cd in :status and co_id in :cids ", nativeQuery = true)
public Page<Object> findByStatusAndCompanyIdIn(#Param("status") String status, #Param("cids") List<Long> companyIds,
#Param("userStatus") List<GroupUserStatus> userStatus,
#Param("itemStatus") List<GroupItemStatus> itemStatus, Pageable pageable);
Now the requirement is also that these records are to be sorted on any of the column in select part. So, if user passes numberOfItems, the records are to be sorted on it. But I am facing an issue here because if I pass Sort parameter as numberOfItems, spring prepends an a. before numberOfItems which results in error that not able to find a.numberOfItems.
Is there a way I can stop spring from prepending table alias while creating a query with Sort, or should I write my logic in a different approach
Making my comment an answer so the question can be marked as answered:
Wrap the whole select in another one: select * from (<your current select>) x
I have solved the issue by creating a projection. (Kotlin was used but you’ll get the gist.)
class ShowRepository : JpaRepository<Int, Show> {
#Query("SELECT s AS show, (CASE WHEN (s.status = 'scheduled') THEN s.scheduledStartTime ELSE s.startTime END) AS time FROM Show s")
fun findShows(pageable: Pageable): Page<ShowWithTime>
}
interface ShowWithTime {
val show: Show,
val time: Date?
}
This allows Spring-Data to work its full magic, and using Sort.by(Order.desc("time")) works like a charm.
I’ve written it up with a little bit more detail here: Sorting by a Non-Entity Field.
I have a complexe application and I need to retrieve and filter 1000~5000 object for an xls export. Each object having multiple eager relationship (I need them for the export).
If I retrieve all the objects and their relationship as it is, I got some stackoverflow error.
Generaly when I need to make a big export, in order to make it efficient I use a DTO object with an #Query like this :
public interface myRepository extends JpaRepository<Car, Long> {
#Query("SELECT new com.blabla.myCustomObject(p.name, p.surname, c.model, c.number ...) "
+ "FROM Car c "
+ "LEFT JOIN c.person p "
+ "WHERE ... ")
List<myCustomObject> getExportCustomObject();
}
The problem is that the #Query is static and I want to add dynamic filter to my Query (Specifications, Criteria or some other system...)
How to do it ?
Specification cannot be used because this is only the where clause.
But you can use Criteria API. Here's an example. The BasicTeacherInfo is the DTO:
CriteriaQuery<BasicTeacherInfo> query = cb.createQuery(BasicTeacherInfo.class);
Root<Teacher> teacher = query.from(Teacher.class);
query.multiselect(teacher.get("firstName"),teacher.get("lastName"));
List<BasicTeacherInfo> results = em.createQuery(query).getResultList();
You can use #Param annotation to pass dynamic values to HQL, something like:
#Query("SELECT new com.blabla.myCustomObject(p.name, p.surname, c.model, c.number ...) "
+ "FROM Car c "
+ "LEFT JOIN c.person p "
+ "WHERE c.status = :status AND p.name = :name")
List<myCustomObject> getExportCustomObject(
#Param("status") Integer status,
#Param("name") String name
);
Below is one of the possible way where you can try to add offset and limit into your query you can make it dynamic with the help off placeholders.
Below is an sample pseudo code for reference:
Dao Layer:
#Query(value="SELECT e FROM tablename e WHERE condition_here ORDER BY e.id offset :offset limit:limit ")
public returnType yourMethod(String name, int offset, int limit);
Service Layer:
long count = number of records in db.
int a = // number of records to be fetched on each iterations
int num_iterations = count % a ;
int additionalrecords = count / a;
int start= 0;
while(num_iterations>0)
{
dao.yourMethod(start,a);
start = start+a;
count--;
// write your data to excel here
}
dao.yourMethod(start,additionalrecords);
Hope it is helpful.
I am a novice to use jdbc and I have some problems.
I use hql to search data in MySQL, and the result is Query type. I don't know how to get the data from the "Query".This is my code:
final String hql = "select app.appkey,app.type from " + getClassName() +
"app where app.appkey<>'no-appkey' group by app.type";
Query query = getEntityManager().createQuery(hql);
Thanks a lot.
You have to do the following:
final String hql = "select app.appkey,app.type from " + getClassName() + " app where app.appkey<>'no-appkey' group by app.type";
Query query = getEntityManager().createQuery(hql);
query.list(); //or query.getSingleResult();
query.list() will give a list of results.
query.getSingleResult() will give you a object.
You can check this.
If you are expecting a list of results, so:
List<Object[]> results = query.getResultList();
If you are expect one single result:
Object[] result = query.getSingleResult(); // if more than one result was found, this method will throw a NonUniqueResultException
If column information will be stored in a position of the Object array. Example:
String appKey = (String) result[0];
String appType = (String) result[1];
But work with Object array is not good. Try to use Dto, like explained here.
i wan to retrieve data from query involving many tables.
i have a query as follows
String sql = "SELECT "
+ "s.Food_ID AS 'Sales_FoodID', "
+ "f.Food_Name AS 'foodName' "
+ "FROM Ordering o, Sales s, Food f"
+ " WHERE o.Table_No = " + tableNo + ""
+ " AND o.Paid = '" + NOT_PAID + "'"
+ " AND s.Order_ID = o.Order_ID"
+ " AND f.Food_ID = s.Food_ID;";
resultSet = statement.executeQuery(sql);
no error were found when i run the program, but after i add this line to get a table's column data:
String orderID = resultSet.getString("foodName");
i'm given this error:
java.sql.SQLException: Column not found
anyone know why?
You have to use next() method.
You should know that ResultSet is implicitly positioned on position before first row so you need to call next to get current position and if is valid, it returns true, else returns false (cursor is positioned after the last row).
rs = statement.executeQuery(sql);
while (rs.next()) {
String orderID = rs.getString(2);
}
Note: You can use also rs.getString(<columnName>) but in case when you know how your statement looks i recommend to you use index instead of columnName.
After calling the resultSet.executeQuery() you need to call the next() to pulling the records from db
after that you can call setXxx() provided by Java API
I have an object with two different integer properties in it, and I'm trying to get a a new object in Linq to Entities, combining two integer properties from the same object as concatenated strings, as follows
List<DateRange> collection = (from d in context.dates
select new DateRange
{
DateString = from s in context.Seasons
where s.SeasonID = d.DateID
select string.Format("{0} - {1}", s.StartYear, s.EndYear) }
).ToList<DateRange>();
The string concatenation of the years will not compile.
This will work in LINQ to Objects, provided that each object in objects is a class or struct containing "Number1" and "Number2" fields or properties:
var results = from o in objects
select string.Format("{0} - {1}", o.Number1, o.Number2);
(However, your original should work, as well....)
Assuming you are connecting to a database via LINQ to SQL/Entities, then the String.Format call will likely fail, as with those providers, the select clause is executed within the database. Not everything can be translated from C# into SQL.
To convert your database results into a string like you want to, the following should work:
var temp = (
from d in context.dates
from s in context.Seasons
where s.SeasonID == d.DateID
select new { s.StartYear, s.EndYear }
).ToList(); // Execute query against database now, before converting date parts to a string
var temp2 =
from t in temp
select new DateRange
{
DateString = t.StartYear + " - " + t.EndYear
};
List<DateRange> collection = temp2.ToList();
EDIT:
I had an additional thought. The String.Format call is most likely the problem. I am not sure if it would work or not, but what about a plain-jane concat:
List<DateRange> collection =
(from d in context.dates
select new DateRange
{
DateString = from s in context.Seasons
where s.SeasonID = d.DateID
select s.StartYear + " - " + s.EndYear
}
).ToList<DateRange>();
Your original code works if you really want what you wrote. However, if your really want to get from
var objects = new MyObject[]{
new MyObject {Int1 = 1, Int2 = 2},
new MyObject {Int1 = 3, Int2 = 4}};
something like 1 - 2 - 3 - 4 you can write
var strings = objects.Select(o = > string.Format("{0} - {1}", o.Int1, o.Int2).ToArray();
var output = string.Join(" - ", strings);
using System.Data.Objects.SqlClient;
:
:
List<DateRange> collection = (from d in context.dates
select new DateRange
{
DateString = from s in context.Seasons
where s.SeasonID = d.DateID
select SqlFunctions.StringConvert((double)s.StartYear) + " - " +
SqlFunctions.StringConvert((double)s.EndYear)
}).ToList<DateRange>();
The StringConvert method gets converted into the proper conversion function when the LINQ statement is converted to SQL for execution on the server.