Membuat Paging pada JSP

Hm…, lama nih ga nulis artikel tentang JSP, habis, nasib ngurusin PHP mulu, , he..he… Di sini saya memodifikasi kelas pagination punya CodeIgniter (PHP), cuma copy logika nya aja, karena pagination nya emang udah bagus (bilang aja ga bisa buat sendiri, xi..xi…xi…).

Hal pertama yang harus ditentukan adalah, apa yang akan kita list dan kita paging. Saya di sini akan memberi contoh tentang paging menggunakan PostgreSQL, dengan table orang dengan field2 nya id, nama, alamat, simple kan ?
OK, sekarang kita siapkan modelnya :

1. Kelas Koneksi

package beanpackage;
import java.sql.*;
/**
 *
 * @author samsonasik
 */
public class Koneksi {

 private Connection con=null;
 private Statement st=null;
 private ResultSet rs=null;

 public Koneksi()throws SQLException,ClassNotFoundException {
 Class.forName("org.postgresql.Driver");
 con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/ikhsandb","ikhsan","123456");
 st = con.createStatement();
 }

 public void seleksi(String s) throws SQLException{
 rs = st.executeQuery(s);
 }

 public boolean getNext() throws SQLException{
 return rs.next();
 }

 public String getText(String t) throws SQLException{
 return rs.getString(t);
 }

 public int getInt(String t) throws Exception {
 return rs.getInt(t);
 }
}

2. Kelas Pagination (library pagination nya )

package beanpackage;

/**
 *
 * @author samsonasik
 */
//dimodifikasi dari kelas paginationnya codeIgniter
public class Pagination {
    public int totalrows = 0;
    public int numlink   = 2;
    public int curpage   = 0;
    public int perpage = 2;
    public String firstlink = "First";
    public String nextlink = "Next";
    public String prevlink = "Previous";
    public String lastlink = "Last";

    public String createlinks(int halaman) {
        if ( (this.totalrows==0) || (this.perpage==0)) {
            return "";
        }

        int numpage = this.totalrows / this.perpage ;
        int sisa  = this.totalrows % this.perpage;
        if (sisa > 0 ){
            numpage = numpage + 1;
        }

        if (numpage==1) {
            return "";
        }

        try {
            this.curpage = halaman;
        } catch (Exception e) {
            this.curpage = 1;
        }

        try {
            this.curpage = (int) this.curpage;
        } catch (Exception e) {
            this.curpage = 1;
        }

        if (this.curpage > this.totalrows)
        {
            this.curpage = (numpage -1 ) * this.perpage ;
        }

        if (this.curpage < 1 ) {
            this.curpage = 1;
        }

        int uri_page_number = this.curpage ;
        int start = ((this.curpage - this.numlink) > 0 ) ? this.curpage - (this.numlink -1) : 1;
        int end   = ((this.curpage + this.numlink < numpage)) ? this.curpage + this.numlink : numpage;

        //inisialisasi ...
        String theoutput = "";
        //Render first link
        if (this.curpage > (this.numlink +1))
        {
            if (this.curpage <= numpage) {
                theoutput +="<a href=\"?page=1\">"+this.firstlink+"</a>nbsp;";
            } else {
                theoutput +="";
            }
        } 

        //Render Previous Link
        if (this.curpage !=1) {
            if (this.curpage <= numpage) {
                theoutput +="<a href=\"?page="+(this.curpage-1)+"\">"+this.prevlink+"</a>nbsp;";
            } else {
                theoutput +="";
            }
        }

        //render digit link

        for (int loop = start -1; loop<end;loop++) {
            if (this.curpage <= numpage) {
            if (this.curpage == (loop+1)) {
                theoutput += loop+1+"nbsp;";
            } else {
                theoutput += "<a href=\"?page="+(loop+1)+"\">"+(loop+1)+"</a>nbsp;";
            }
            } else {
                theoutput +="";

            }
        }

        //render the next link
        if (this.curpage < numpage) {
            theoutput += "<a href=\"?page="+(this.curpage+1)+"\">"+this.nextlink+"</a>nbsp;";
        } else {
            theoutput +="";
        }

        //render the last link
        if ((this.curpage + this.numlink)<numpage) {
            theoutput += "<a href=\"?page="+numpage+"\">"+this.lastlink+"</a>";
        }

        return theoutput;
    }
}

3. Kelas Orang (Model dari table orang)

package beanpackage;

import java.sql.SQLException;
import java.util.ArrayList;
/**
 *
 * @author samsonasik
 */
public class Orang {
    private int id;
    private String nama, alamat;

    public Orang(){ }

    public Orang(int id, String n,String a){
       this.id = id;
       this.nama = n;
       this.alamat = a;
    }

    public void setNama(String n)
    {
        this.nama = n;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setAlamat(String al)
    {
        this.alamat = al;
    }

    public String getNama()
    {
        return nama;
    }

    public String getAlamat()
    {
        return alamat;
    }

    //seleksi offset limit
    public ArrayList<Orang> seleksi(int offset, int limit) throws SQLException, ClassNotFoundException
    {

        ArrayList<Orang> temp = new ArrayList<Orang>();
        try {
            Koneksi kon = new Koneksi();
            kon.seleksi("select * from orang offset '"+offset+"' limit '"+limit+"'");

            while (kon.getNext()) {
                temp.add(new Orang(kon.getInt("id"), kon.getText("nama"), kon.getText("alamat")));
            }
        } catch(Exception e) {}

        return temp;
    }

    public int getJml() {
        int jml  = 0;
        try {
            Koneksi kon = new Koneksi();
            kon.seleksi("select count(*) as jml from orang");
            if (kon.getNext()) jml = kon.getInt("jml");
        } catch (Exception e){}
        return jml;
    }
}

Nah, kalau sudah tuh, kita buat servletnya, ga akan saya tulis lengkap

deh kaya’nya, cuma isi method nya aja yang memanggil

model-model yang ada.

.............
        ArrayList<Orang> temp = new ArrayList<Orang>();
        PrintWriter out = response.getWriter();
        try {
            Orang  org = new Orang();
            int page = 0;
            try {
                page = Integer.parseInt(request.getParameter("page"));
            } catch (Exception e) {
                page = 1;
            }

            Pagination pgn = new Pagination();
            pgn.totalrows = org.getJml();

            temp = org.seleksi(page*pgn.perpage-pgn.perpage,pgn.perpage);
            request.setAttribute("temp", temp);
            request.setAttribute("perpage",pgn.perpage);
            request.setAttribute("paging", pgn.createlinks(page));

        } catch(Exception e) {

            out.print("terjadi kesalahan koneksi");
            out.close();
        }
        request.getRequestDispatcher("/testlist.jsp").forward(request, response);
................

Jangan lupa konfigurasi web.xml nya, udah bisa kan ?

Terakhir adalah view :

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
${paging}
<table border="1" cellpadding="1" cellspacing="1">
<tr>
<td>No</td>
<td>Id</td>
<td>Nama</td>
<td>Alamat</td>
</tr>
<c:catch var ="catchException">
    <c:if test="${param.page eq null || param.page eq '1'}">
        <c:set var="no" value="0"/>
    </c:if>
    <c:if test="${param.page gt '1'}">
        <c:set var="no" value="${param.page * perpage - perpage }"/>
    </c:if>
  </c:catch>

    <c:if test="${catchException !=null}">
        <c:set var="no" value="0"/>
    </c:if>

    <c:forEach var="testlist" items="${temp}">
        <c:set var="no" value="${no +1}"/>
<tr>
<td>${no} .</td>
<td>${testlist.id}</td>
<td>${testlist.nama}</td>
<td>${testlist.alamat}</td>
</tr>
</c:forEach></table>
${paging}

Simple kan ? selamat mencoba