Displaying a huge amount of data in a single page was not good, to avoid this will use Pagination concept. It means dividing huge data into smaller parts and showing each smaller one as a page representation. In Technical, huge data is nothing but Resultset, Resultset has many no of rows, by taking some no of rows and displaying in jsp page as a different pages. For this, generally follows approach as the entire Resultset put in a session or any memory and performing presentation logic to display few rows by page by page. Instead of this, will implement Pagination based on query using Hibernate. Each time the query will fetch required data as per the pagination.
Implementation in Eclipse:
Pre requisites:
1. Hibernate3. (Download hiberante3 jar file
from www.hibernate.org)
2. Any RDBMS (Here Oracle9i/10g jar file ojdbc14.jar)
3. jstl jar file
3. java1.5 or above
Step1:
Creating a sample table named Emp with 4 columns.
CREATE TABLE "BABU"."EMP"
( "EMPNO" LONG,
"ENAME" VARCHAR2(40 BYTE),
"JOB" VARCHAR2(40 BYTE),
"SAL" FLOAT(126)
) ;
Entering sample data: 11 rows
"EMPNO" "ENAME" "JOB" "SAL"
"1" "ram" "se" "40"
"2" "babu" "tl" "80"
"3" "cheekuri" "pl" "120"
"4" "bob" "ret" "343"
"5" "fgh" "t" "45"
"6" "gfh" "tr" "45"
"7" "martin" "PM" "200"
"8" "luther4" "MD" "500"
"9" "kelvin" "CEO" "1000"
"10" "Mike" "SM" "100"
"11" "Eric" "NE" "70"
Step2: Create a project(Eg.HibernatePaging) in eclipse using new project (dynamic web project)
Step3 : Place the jars(hibernate3.jar,ojdbc14.jar,jstl.jar) in lib folder or configure in project build path.
Step4:
Here creating a package com.paging.classes,with in creating a hibernate mapping file to represent Emp Table.
Employee.hbm.xml
<?xml
version="1.0"?>
<!DOCTYPE
hibernate-mapping
PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class
name="com.paging.classes.Employee"
table="Emp">
<id
name="empId"
column="EMPNO"
type="long">
<generator
class="native"/>
</id>
<property
name="empName"
column="ENAME"
/>
<property
name="empJob"
column="JOB"
/>
<property
name="empSal"
column="SAL"
type="float"/>
</class>
</hibernate-mapping>
Step5: Creating a bean class to hold the data.
create a class as like this
package com.paging.classes;
public
class Employee {
public
long
empId;
public String empName;
public String empJob;
public
float
empSal;
public
long getEmpId() {
return
empId;
}
public
void setEmpId(long empId) {
this.empId = empId;
}
public String getEmpJob() {
return
empJob;
}
public
void setEmpJob(String empJob) {
this.empJob = empJob;
}
public String getEmpName() {
return
empName;
}
public
void setEmpName(String empName) {
this.empName = empName;
}
public
float getEmpSal() {
return
empSal;
}
public
void setEmpSal(float empSal) {
this.empSal = empSal;
}
}
Step6: Write a hibernate.cfg.xml file in src folder.
<?xml
version='1.0'
encoding='utf-8'?>
<!DOCTYPE
hibernate-configuration
PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property
name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property
name="connection.url">jdbc:oracle:thin:@localhost:1521/XE</property>
<property
name="connection.username">babu</property>
<property
name="connection.password">babu</property>
<property
name="dialect">org.hibernate.dialect. Oracle9Dialect</property>
<property
name="hibernate.current_session_context_class">thread</property>
<mapping
resource="com/paging/classes/Employee.hbm.xml"
/>
</session-factory>
</hibernate-configuration>
Step 7:
Creating a Data Access Object(DAO)
Here DAO class named as DAO.java
package com.paging.classes;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public
class DAO {
private
static
int
pageSize = 3;
public
static
List getData(int pageNumber) {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.getCurrentSession();
List result = null;
try {
session.beginTransaction();
System.out.println("$$$$$$$$$$$$$$$$$$"+pageNumber);
Query query = session.createQuery("from Employee");
query = query.setFirstResult(pageSize * (pageNumber - 1));
//firstResult - a row number, numbered from 0
query.setMaxResults(pageSize);
//maximum no of rows from the staring row
result = query.list();
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public
static
int getTotalData() {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.getCurrentSession();
int actual = 0,result=0;
try {
session.beginTransaction();
Query query = session.createQuery("from Employee");
// query = query.list()
// query.setMaxResults(pageSize);
result = query.list().size();
System.out.println("Total no of rows"+result);
if(result!=0){
actual=result/3;
System.out.println("Total possible pages"+actual);
if(result%3!=0)
actual= actual+1;
}
System.out.println("Total possible pages"+actual);
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
}
return actual;
}
}
Pagination needs to specify bounds upon result set (the maximum number of rows want to retrieve and / or the first row want to retrieve) you should use methods of the Query interface:
Query q = sess.createQuery("from TableName");
q.setFirstResult(No of rows);
q.setMaxResults(maximum no of results per page i.e pagesize);
List cats = q.list();
In the above getData method ,passing page number as argument ,to fetch the data of that page and returning as List.
Step8:
Retrieving the data in jsp page, here jsp named as paging.jsp
<jsp:root
version="1.2"
xmlns:jsp="http://java.sun.com/JSP/Page"
xmlns:c="urn:jsptld:http://java.sun.com/jsp/jstl/core">
<jsp:directive.page
contentType="text/html; charset=UTF-8"
/>
<jsp:scriptlet>
int pageNumber=1;
if(request.getParameter("page") != null) {
session.setAttribute("page", request.getParameter("page"));
pageNumber = Integer.parseInt(request.getParameter("page"));
} else {
session.setAttribute("page", "1");
}
String nextPage = (pageNumber +1) + "";
String prevPage = (pageNumber -1) + "";
session.setAttribute( "EmpList", com.paging.classes.DAO.getData(pageNumber));
// session.setAttribute( "totalPages", com.paging.classes.DAO.getTotalData());
System.out.println(((java.util.List)session.getAttribute("EmpList")).size());
String myUrl = "paging.jsp?page=" + nextPage;
String myUrl1 = "paging.jsp?page=" + prevPage;
System.out.println(myUrl);
pageContext.setAttribute("totalPages", com.paging.classes.DAO.getTotalData());
pageContext.setAttribute("myUrl", myUrl);
pageContext.setAttribute("myUrl1", myUrl1);
</jsp:scriptlet>
<h2
align="center">Emp Table with Display tag</h2>
<jsp:useBean
id="EmpList"
scope="session"
type="java.util.List"></jsp:useBean>
<table>
<tr>
<th>Employee Id</th>
<th>Name</th>
<th>Job</th>
<th>Salary</th>
</tr>
<c:forEach
items="${EmpList}" var="emp"
begin="0"
end="10">
<tr>
<td><c:out
value="${emp.empId}"></c:out></td>
<td><c:out
value="${emp.empName}"></c:out></td>
<td><c:out
value="${emp.empJob}"></c:out></td>
<td><c:out
value="${emp.empSal}"></c:out></td>
</tr>
</c:forEach>
<tr><td><a
href="${pageScope.myUrl1}">Previous Page</a></td>
<c:forEach
var="i"
begin="1"
end="${totalPages}">
<td><a
href="paging.jsp?page=${i}"><c:out
value="${i}" />
</a></td>
</c:forEach><td><a
href="${pageScope.myUrl}">nextPage</a></td>
</tr>
</table>
</jsp:root>
By accessing DAO class getData method and fetching result set placing in session corresponding page data instead of entire resultset.
session.setAttribute( "EmpList", com.paging.classes.DAO.getData(pageNumber));
Total no of pages return by com.paging.classes.DAO.getTotalData(pageNumber) method.
Using jstl tags ,populating data on jsp page.
Here we can observe two approaches of Pagination
1, Using PreviousPage & NextPage approach
2, By showing page numbers
Output will be:
Approach to write Hibernate XML Config file:
The XML configuration file is by default expected to be in the root o your CLASSPATH. Here is an example:
As you can see, the advantage of this approach is the externalization of the mapping file names to configuration. The hibernate.cfg.xml is also more convenient once you have to tune the Hibernate cache. Note that is your choice to use either hibernate.properties or hibernate.cfg.xml, both are equivalent, except for the above mentioned benefits of using the XML syntax.
Property: hibernate.dialect
The classname of a Hibernate org.hibernate.dialect.Dialect which allows Hibernate to generate SQL optimized for a particular relational database. eg. full.classname.of.Dialect
In most cases Hibernate will actually be able to chose the correct org.hibernate.dialect.Dialect implementation to use based on the JDBC metadata returned by the JDBC driver
SQL Dialects :You should always set the hibernate.dialect property to the correct org.hibernate.dialect.Dialect subclass for your database. If you specify a dialect, Hibernate will use sensible defaults for some of the other properties listed above, saving you the effort of specifying them manually.
Hibernate SQL Dialects (hibernate.dialect)
RDBMS Dialect DB2 org.hibernate.dialect.DB2Dialect DB2 AS/400 org.hibernate.dialect.DB2400Dialect DB2 OS390 org.hibernate.dialect.DB2390Dialect PostgreSQL org.hibernate.dialect.PostgreSQLDialect MySQL org.hibernate.dialect.MySQLDialect MySQL with InnoDB org.hibernate.dialect.MySQLInnoDBDialect MySQL with MyISAM org.hibernate.dialect.MySQLMyISAMDialect Oracle (any version) org.hibernate.dialect.OracleDialect Oracle 9i/10g org.hibernate.dialect.Oracle9Dialect Sybase org.hibernate.dialect.SybaseDialect Sybase Anywhere org.hibernate.dialect.SybaseAnywhereDialect Microsoft SQL Server org.hibernate.dialect.SQLServerDialect SAP DB org.hibernate.dialect.SAPDBDialect Informix org.hibernate.dialect.InformixDialect HypersonicSQL org.hibernate.dialect.HSQLDialect Ingres org.hibernate.dialect.IngresDialect Progress org.hibernate.dialect.ProgressDialect Mckoi SQL org.hibernate.dialect.MckoiDialect Interbase org.hibernate.dialect.InterbaseDialect Pointbase org.hibernate.dialect.PointbaseDialect FrontBase org.hibernate.dialect.FrontbaseDialect Firebird org.hibernate.dialect.FirebirdDialect Let me know if you have any queries on this.
Thanks,
Cheekuri.
Pagination:
Is Tamanna dominating Trisha ?
15 years ago
Posts
thanks, I just tried this code, and i found it very useful, thank you again
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