Hi all,
I'm trying to do a very simple task. I've 2 entities, Account and Customer with a
OneToOne relation, and an AccountRepository, I want to load, in a web page, a paged list of Accounts
using Spring Data for JPA/Hibernate.
I'm able to do this but if I look to the generated SQL queries I see that one query for single account is made to fetch the associate customer:
Generated SQL queries
This is a waste of resources and has very poor performace.
Is there a way to get the paged list of accounts with one query?
Here my code:
MVC Controller
MVC View
Jpa Repository
Jpa Entities
Thank you in adevance
Andrea
I'm trying to do a very simple task. I've 2 entities, Account and Customer with a
OneToOne relation, and an AccountRepository, I want to load, in a web page, a paged list of Accounts
using Spring Data for JPA/Hibernate.
I'm able to do this but if I look to the generated SQL queries I see that one query for single account is made to fetch the associate customer:
Generated SQL queries
Code:
Hibernate: select count(*) as col_0_0_ from Account account0_
Hibernate: select account0_.id as id1_0_, account0_.expiryDate as expiryDa2_0_ from Account account0_ cross join Customer customer1_ where account0_.id=customer1_.id order by customer1_.lastname asc, customer1_.firstname asc limit ?
Hibernate: select customer0_.id as id1_1_1_, customer0_.firstname as firstnam2_1_1_, customer0_.lastname as lastname3_1_1_, account1_.id as id1_0_0_, account1_.expiryDate as expiryDa2_0_0_ from Customer customer0_ left outer join Account account1_ on customer0_.id=account1_.id where customer0_.id=?
Hibernate: select customer0_.id as id1_1_1_, customer0_.firstname as firstnam2_1_1_, customer0_.lastname as lastname3_1_1_, account1_.id as id1_0_0_, account1_.expiryDate as expiryDa2_0_0_ from Customer customer0_ left outer join Account account1_ on customer0_.id=account1_.id where customer0_.id=?
Hibernate: select customer0_.id as id1_1_1_, customer0_.firstname as firstnam2_1_1_, customer0_.lastname as lastname3_1_1_, account1_.id as id1_0_0_, account1_.expiryDate as expiryDa2_0_0_ from Customer customer0_ left outer join Account account1_ on customer0_.id=account1_.id where customer0_.id=?
Hibernate: select customer0_.id as id1_1_1_, customer0_.firstname as firstnam2_1_1_, customer0_.lastname as lastname3_1_1_, account1_.id as id1_0_0_, account1_.expiryDate as expiryDa2_0_0_ from Customer customer0_ left outer join Account account1_ on customer0_.id=account1_.id where customer0_.id=?
......Is there a way to get the paged list of accounts with one query?
Here my code:
MVC Controller
Code:
public class HomeController {
@Autowired
private AccountRepository accountRepository;
private final int pageSize = 20;
@SuppressWarnings("unused")
@RequestMapping(value = "/", method = RequestMethod.GET)
public String home(Locale locale, Model model) {
return "home";
}
@RequestMapping(value = "/pages/{pageNumber}", method = RequestMethod.GET)
public String getItemsPage(@PathVariable Integer pageNumber, Model model) {
PageRequest page = new PageRequest(pageNumber, pageSize, Direction.ASC,
"customer.lastname", "customer.firstname");
Page<Account> accounts = accountRepository.findAll(page);
int current = accounts.getNumber() + 1;
int begin = Math.max(1, current - 5);
int end = Math.min(begin + pageSize, accounts.getTotalPages());
model.addAttribute("beginIndex", begin);
model.addAttribute("endIndex", end);
model.addAttribute("currentIndex", current);
model.addAttribute("accounts", accounts);
return "page";
}
}Code:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ page session="false"%>
<c:url var="firstUrl" value="/pages/1" />
<c:url var="lastUrl" value="/pages/${accounts.totalPages}" />
<c:url var="prevUrl" value="/pages/${currentIndex - 1}" />
<c:url var="nextUrl" value="/pages/${currentIndex + 1}" />
<html>
<head>
<title>Page</title>
</head>
<body>
<h1>Paged List</h1>
<a href='<c:url value="/"/>'>Home</a>
<table width="100%" border="1">
<thead>
<tr>
<td>Counter: ${accounts.getTotalElements()}</td>
<td>Name</td>
<td>Date</td>
<td>Width</td>
<td>Height</td>
</TR>
</thead>
<tbody>
<c:forEach items="${accounts.getContent()}" var="item"
varStatus="status">
<tr class="${status.count % 2 == 0 ? 'even' : 'odd'}">
<td>${status.count})</td>
<td>${item.id}</td>
<td>${item.expiryDate})</td>
<td>${item.customer.firstname}</td>
<td>${item.customer.lastname}</td>
<td></td>
</tr>
</c:forEach>
</tbody>
</table>
<div class="pagination">
<ul>
<c:choose>
<c:when test="${currentIndex == 1}">
<li class="disabled"><a href="#"><<</a></li>
<li class="disabled"><a href="#"><</a></li>
</c:when>
<c:otherwise>
<li><a href="${firstUrl}"><<</a></li>
<li><a href="${prevUrl}"><</a></li>
</c:otherwise>
</c:choose>
<c:forEach var="i" begin="${beginIndex}" end="${endIndex}">
<c:url var="pageUrl" value="/pages/${i}" />
<c:choose>
<c:when test="${i == currentIndex}">
<li class="active"><a href="${pageUrl}"><c:out
value="${i}" /></a></li>
</c:when>
<c:otherwise>
<li><a href="${pageUrl}"><c:out value="${i}" /></a></li>
</c:otherwise>
</c:choose>
</c:forEach>
<c:choose>
<c:when test="${currentIndex == accounts.totalPages}">
<li class="disabled"><a href="#">></a></li>
<li class="disabled"><a href="#">>></a></li>
</c:when>
<c:otherwise>
<li><a href="${nextUrl}">></a></li>
<li><a href="${lastUrl}">>></a></li>
</c:otherwise>
</c:choose>
</ul>
</div>
</body>
</html>Jpa Repository
Code:
public interface AccountRepository extends JpaRepository<Account, Long> {
}Jpa Entities
Code:
@Entity
@Table(name = "Account")
public class Account {
@Id
private Long id;
@OneToOne(mappedBy = "account", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private Customer customer;
@Temporal(TemporalType.DATE)
private Date expiryDate;
public Long getId() {
return id;
}
public Customer getCustomer() {
return customer;
}
public Date getExpiryDate() {
return expiryDate;
}
public void setId(Long id) {
this.id = id;
}
public void setCustomer(Customer customer) {
this.customer = customer;
}
public void setExpiryDate(Date expiryDate) {
this.expiryDate = expiryDate;
}
}
@Entity
@Table(name = "Customer")
public class Customer {
@Id
private Long id;
private String firstname;
private String lastname;
@PrimaryKeyJoinColumn
Account account;
public Long getId() {
return id;
}
public String getFirstname() {
return firstname;
}
public String getLastname() {
return lastname;
}
public void setId(Long id) {
this.id = id;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
}Thank you in adevance
Andrea