Ekiras Replica: Pagination

Showing posts with label Pagination. Show all posts

Pagination in Spring Hibernate Mvc application

Points To Remember

Create a Pagination Taglib using this example.
Add Bootstrap css and js in the jsp you want to do pagination and include the taglib in the jsp.

Pagination in Spring Hibernate Application using Bootstrap

Create a Domain Person.
Create a Service PersonService
Create a Dao PersonDao.
Create a Controller PersonController.
Create a Taglib PaginationTaglib.

Person.java

package com.ekiras.domain;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="person")
public class Person {

 public Person(){};
 public Person(String name,Integer age){
  this.name = name;
  this.age  = age;
 }
 
 
 @Id
 @GeneratedValue(strategy=GenerationType.AUTO)
 @Column(name="id")
 private Long id;
 
 @Column(name="name")
 private String name;
 
 @Column(name="age")
 private Integer age;

       // GETTERS and SETTERS

PersonService.java

package com.ekiras.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.ekiras.dao.PersonDAO;
import com.ekiras.domain.Person;

@Service
public class PersonService {

 @Autowired
 private PersonDAO personDAO;
 
 
 public List<Person> list(Integer offset, Integer maxResults){
  return personDAO.list(offset, maxResults);
 }
 
 public Long count(){
  return personDAO.count();
 }
 
 public void save(){
  personDAO.save();
 }
 
}

PersonDAO.java

package com.ekiras.dao;

import java.util.List;

import org.hibernate.SessionFactory;
import org.hibernate.criterion.Projections;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.ekiras.domain.Person;

@Repository
@Transactional
public class PersonDAO {

 @Autowired 
 private SessionFactory sessionFactory;
 
 @SuppressWarnings("unchecked")
 @Transactional
 public List<Person> list(Integer offset, Integer maxResults){
  return sessionFactory.openSession()
    .createCriteria(Person.class)
    .setFirstResult(offset!=null?offset:0)
    .setMaxResults(maxResults!=null?maxResults:10)
    .list();
 }
 
 
 public Long count(){
  return (Long)sessionFactory.openSession()
    .createCriteria(Person.class)
    .setProjection(Projections.rowCount())
    .uniqueResult();
 }
 
 
 public void save(){
  for(int itr=1;itr <= 100 ; itr++){
   Person person = new Person("Person_"+itr,Math.max(25, (itr%2)*35));
   sessionFactory.openSession()
   .save(person);
  }
  
  
  
 }
 
}

PersonController.java

package com.ekiras.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.ekiras.service.PersonService;

@Controller
@RequestMapping(value="/person")
public class PersonController {

 @Autowired
 private PersonService personService;
 
 @RequestMapping(value="/list")
 public String list(Model model, Integer offset, Integer maxResults){
  model.addAttribute("persons", personService.list(offset, maxResults));
  model.addAttribute("count", personService.count());
  model.addAttribute("offset", offset);
  return "/person/list";
 }
 
 @RequestMapping(value="/save")
 public String save(){
  personService.save();
  return "/person/list";
 }
 
}

PaginationTaglib.java

package com.ekiras.taglib;

import java.io.Writer;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;

public class PaginationTaglib extends SimpleTagSupport {
 private String uri;
 private int offset;
 private int count;
 private int max = 10;
 private int steps = 10;
 private String previous = "Previous";
 private String next = "Next";

 private Writer getWriter() {
  JspWriter out = getJspContext().getOut();
  return out;
 }

 @Override
 public void doTag() throws JspException {
  Writer out = getWriter();

  try {
   out.write("<nav>");
   out.write("<ul class=\"pagination\">");
   
   if(offset<steps)
    out.write(constructLink(1, previous, "disabled", true));
   else
    out.write(constructLink(offset-steps, previous, null, false));
   
   for(int itr=0;itr<count;itr+=steps) {
    if(offset==itr)
     out.write(constructLink((itr/10+1)-1 *steps, String.valueOf(itr/10+1), "active", true));
    else
     out.write(constructLink(itr/10*steps, String.valueOf(itr/10+1), null , false));
   }

   if(offset+steps>=count)
    out.write(constructLink(offset+steps, next, "disabled", true));
   else
    out.write(constructLink(offset+steps, next, null , false));
   
   
   out.write("</ul>");
   out.write("</nav>");
  } catch (java.io.IOException ex) {
   throw new JspException("Error in Paginator tag", ex);
  }
 }


 private String constructLink(int page, String text, String className, boolean disabled) {
  StringBuilder link = new StringBuilder("<li");
  if (className != null) {
   link.append(" class=\"");
   link.append(className);
   link.append("\"");
  }
  if(disabled)
   link.append(">").append("<a href=\"#\">"+text+"</a></li>");
  else
   link.append(">").append("<a href=\""+uri+"?offset="+page + "\">"+text+"</a></li>");
  return link.toString();
 }

 public String getUri() {
  return uri;
 }

 public void setUri(String uri) {
  this.uri = uri;
 }

 public int getOffset() {
  return offset;
 }

 public void setOffset(int offset) {
  this.offset = offset;
 }

 public int getCount() {
  return count;
 }

 public void setCount(int count) {
  this.count = count;
 }

 public int getMax() {
  return max;
 }

 public void setMax(int max) {
  this.max = max;
 }

 public String getPrevious() {
  return previous;
 }

 public void setPrevious(String previous) {
  this.previous = previous;
 }

 public String getNext() {
  return next;
 }

 public void setNext(String next) {
  this.next = next;
 }

 public int getSteps() {
  return steps;
 }

 public void setSteps(int steps) {
  this.steps = steps;
 }

}

list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
<%@ taglib prefix="tag" uri="/WEB-INF/taglibs/customTaglib.tld"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link rel="stylesheet" type="text/css" href="/css/bootstrap.css" />
<link rel="stylesheet" type="text/css" href="/css/bootstrap.min.css" />
<link rel="stylesheet" type="text/css" href="/css/font-awesome.min.css" />
<title>| Ekiras</title>
</head>
<body>
 <nav class="navbar navbar-default">
 <div class="container-fluid">
  <!-- Brand and toggle get grouped for better mobile display -->
  <div class="navbar-header">
   <button type="button" class="navbar-toggle collapsed"
    data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
    <span class="sr-only">Toggle navigation</span> <span
     class="icon-bar"></span> <span class="icon-bar"></span> <span
     class="icon-bar"></span>
   </button>
   <a class="navbar-brand" href="#">Brand</a>
  </div>

  <!-- Collect the nav links, forms, and other content for toggling -->
  <div class="collapse navbar-collapse"
   id="bs-example-navbar-collapse-1">
   <ul class="nav navbar-nav">
    <li class="active"><a href="#">Link <span class="sr-only">(current)</span></a></li>
    <li><a href="#">Link</a></li>
    <li class="dropdown"><a href="#" class="dropdown-toggle"
     data-toggle="dropdown" role="button" aria-expanded="false">Dropdown
      <span class="caret"></span>
    </a>
     <ul class="dropdown-menu" role="menu">
      <li><a href="#">Action</a></li>
      <li><a href="#">Another action</a></li>
      <li><a href="#">Something else here</a></li>
      <li class="divider"></li>
      <li><a href="#">Separated link</a></li>
      <li class="divider"></li>
      <li><a href="#">One more separated link</a></li>
     </ul></li>
   </ul>
   <form class="navbar-form navbar-left" role="search">
    <div class="form-group">
     <input type="text" class="form-control" placeholder="Search">
    </div>
    <button type="submit" class="btn btn-default">Submit</button>
   </form>
   <ul class="nav navbar-nav navbar-right">
    <li><a href="#">Link</a></li>
    <li class="dropdown"><a href="#" class="dropdown-toggle"
     data-toggle="dropdown" role="button" aria-expanded="false">Dropdown
      <span class="caret"></span>
    </a>
     <ul class="dropdown-menu" role="menu">
      <li><a href="#">Action</a></li>
      <li><a href="#">Another action</a></li>
      <li><a href="#">Something else here</a></li>
      <li class="divider"></li>
      <li><a href="#">Separated link</a></li>
     </ul></li>
   </ul>
  </div>
  <!-- /.navbar-collapse -->
 </div>
 <!-- /.container-fluid --> </nav>

 <div class="container">
  <div class="well">
   <strong>List of Persons</strong>
  </div>
  <table class="table table-stripped">
   <tr>
    <th>S.No</th>
    <th>Name</th>
    <th>Age</th>
   </tr>
   <c:forEach items="${persons}" var="person" varStatus="itr">
    <tr>
     <td>${offset + itr.index +1 }</td>
     <td>${person.name }</td>
     <td>${person.age }</td>
    </tr>
   </c:forEach>
  </table>
  <tag:paginate max="15" offset="${offset}" count="${count}"
   uri="/person/list" next="&raquo;" previous="&laquo;" />
 </div>


 <script type="text/javascript" src="/js/jquery.js"></script>
 <script type="text/javascript" src="/js/bootstrap.min.js"></script>
</body>
</html>

This is how you can do pagination using bootstrap style in spring hibernate mvc application.

Download this example from Github.

How to get results from a fixed position in Hibernate Criteria Query

Points To Remember

Offset may be required to do pagination or get the results after a particular result from the database.
Using offset you can define the first result to be included in the result set from the database.
You can use setFirstResult on the CriteriaQuery to set the first result that you want.

Using offset to get the results

SampleDAO.java

@SuppressWarnings("unchecked")
public List<Person> getCategories(Integer offset){
  return getSession()
   .createCriteria(Person.class)
   .setFirstResult(offset!=null?offset:0)
   .setMaxResults(10)
   .list();
 }

This is how you can set the first result you want to fetch from the database. In this example we have set the first result and the maximum number of records that we need to fetch.

How to create Pagination Taglib in Java, Spring

Points To Remember

Bootstrap is one of the major UI componnet used worldwide, So you may want to implemnt pagination using bootstrap in java , j2ee or spring application. So all you need to do is

Create a Class that will behave like a taglib.
Create a Tld file that will map the tablib class with the jsp's.
Use the taglib on jsp using the tld file.

Create Pagination Taglib for Jsp with Bootstrap.

Following is an example of the a custom taglib built for Bootstrap. This taglib takes in

uri -> action to be hit when clicked.
offset -> the offset of pagination.
count -> total number of elements to be shown.
max -> maximum number of pages to be shown in the pagination bar.
steps -> maximum number of elements to be shown per page.
previous -> text to be shown for previous page link.
next -> text to be shown for next page link.

PaginationTaglib.java

This is a java class that will behave like a taglib on jsp's.

package com.ekiras.taglib;

import java.io.Writer;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;

public class PaginationTaglib extends SimpleTagSupport {
 private String uri;
 private int offset;
 private int count;
 private int max = 10;
 private int steps = 10;
 private String previous = "Previous";
 private String next = "Next";

 private Writer getWriter() {
  JspWriter out = getJspContext().getOut();
  return out;
 }

 @Override
 public void doTag() throws JspException {
  Writer out = getWriter();

  try {
   out.write("<nav>");
   out.write("<ul class=\"pagination\">");
   
   if(offset<steps)
    out.write(constructLink(1, previous, "disabled", true));
   else
    out.write(constructLink(offset-steps, previous, null, false));
   
   for(int itr=0;itr<count;itr+=steps) {
    if(offset==itr)
     out.write(constructLink((itr/10+1)-1 *steps, String.valueOf(itr/10+1), "active", true));
    else
     out.write(constructLink(itr/10*steps, String.valueOf(itr/10+1), null , false));
   }

   if(offset+steps>count)
    out.write(constructLink(offset+steps, next, "disabled", true));
   else
    out.write(constructLink(offset+steps, next, null , false));
   
   
   out.write("</ul>");
   out.write("</nav>");
  } catch (java.io.IOException ex) {
   throw new JspException("Error in Paginator tag", ex);
  }
 }


 private String constructLink(int page, String text, String className, boolean disabled) {
  StringBuilder link = new StringBuilder("<li");
  if (className != null) {
   link.append(" class=\"");
   link.append(className);
   link.append("\"");
  }
  if(disabled)
   link.append(">").append("<a href=\"#\">"+text+"</a></li>");
  else
   link.append(">").append("<a href=\""+uri+"?offset="+page + "\">"+text+"</a></li>");
  return link.toString();
 }

 public String getUri() {
  return uri;
 }

 public void setUri(String uri) {
  this.uri = uri;
 }

 public int getOffset() {
  return offset;
 }

 public void setOffset(int offset) {
  this.offset = offset;
 }

 public int getCount() {
  return count;
 }

 public void setCount(int count) {
  this.count = count;
 }

 public int getMax() {
  return max;
 }

 public void setMax(int max) {
  this.max = max;
 }

 public String getPrevious() {
  return previous;
 }

 public void setPrevious(String previous) {
  this.previous = previous;
 }

 public String getNext() {
  return next;
 }

 public void setNext(String next) {
  this.next = next;
 }

 public int getSteps() {
  return steps;
 }

 public void setSteps(int steps) {
  this.steps = steps;
 }

}

customTaglib.tld

This is the .tld file that defines how to use the java class as a taglib in jsp's

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.1" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd">
  <tlib-version>1.0</tlib-version>
  <short-name>paginator</short-name>
  <uri>/WEB-INF/taglibs/customTaglib.tld</uri>
 
  <tag>
    <name>paginate</name>
    <tag-class>com.ekiras.taglib.PaginationTaglib</tag-class>
    <body-content>empty</body-content>
    
    <attribute>
      <name>next</name>
      <rtexprvalue>true</rtexprvalue>
      <type>java.lang.String</type>
    </attribute>
    <attribute>
      <name>previous</name>
      <rtexprvalue>true</rtexprvalue>
      <type>java.lang.String</type>
    </attribute>
    <attribute>
      <name>uri</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
      <type>java.lang.String</type>
    </attribute>
    <attribute>
      <name>offset</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
      <type>int</type>
    </attribute>
    <attribute>
      <name>count</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
      <type>int</type>
    </attribute>
    <attribute>
      <name>max</name>
      <rtexprvalue>true</rtexprvalue>
      <type>int</type>
    </attribute>
  </tag>
</taglib>

Well that's all that you need to do do create a custom taglib and use it in your jsp's.

<%@ taglib prefix="tag" uri="/WEB-INF/taglibs/customTaglib.tld"%>

You can use this taglib in jsp by including it as mentioned above and use it like shown below.

<tag:paginate max="15" offset="${offset}" count="${count}" uri="${uri}"
  next="&raquo;" previous="&laquo;" />

So this when used in the application may give u an output as shown in image below.