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Tôi muốn thực hiện mã từ này tutorialKhông tính đúng pagination vào trang JSF
tôi cư Oracle bảng với 14 dòng dữ liệu nhưng khi tôi cố gắng để di chuyển giữa các trang JSF mỗi khi trang thứ hai là rỗng:
Đây là mã của trang JSF:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ui="http://java.sun.com/jsf/facelets">
<h:head>
<ui:insert name="header">
<ui:include src="header.xhtml"/>
</ui:insert>
</h:head>
<h:body>
<h1><img src="resources/css/images/icon.png" alt="NVIDIA.com" /> History Center</h1>
<!-- layer for black background of the buttons -->
<div id="toolbar" style="margin: 0 auto; width:1180px; height:30px; position:relative; background-color:black">
<!-- Include page Navigation -->
<ui:insert name="Navigation">
<ui:include src="Navigation.xhtml"/>
</ui:insert>
</div>
<div id="greenBand" class="ui-state-default ui-corner-allh" style="position:relative; top:35px; left:0px;">
<h:graphicImage alt="Dashboard" style="position:relative; top:-20px; left:9px;" value="resources/images/logo_sessions.png" />
</div>
<div id="main" style="margin: 0 auto; width:1190px; height:700px; position:absolute; background-color:transparent; top:105px">
<div id="mainpage" style="margin: 0 auto; width:1190px; height:500px; position:absolute; background-color:transparent; top:80px">
<div id="settingsHashMap" style="width:750px; height:400px; position:absolute; background-color:r; top:20px; left:1px">
<h:form id="form">
<!-- The sortable data table -->
<h:dataTable value="#{SessionsController.dataList}" var="item">
<h:column>
<f:facet name="header">
<h:commandLink value="Account Session ID" actionListener="#{SessionsController.sort}">
<f:attribute name="sortField" value="Account Session ID" />
</h:commandLink>
</f:facet>
<h:outputText value="#{item.aSessionID}" />
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="User ID" actionListener="#{SessionsController.sort}">
<f:attribute name="sortField" value="User ID" />
</h:commandLink>
</f:facet>
<h:outputText value="#{item.userID}" />
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="Activity Start Time" actionListener="#{SessionsController.sort}">
<f:attribute name="sortField" value="Activity Start Time" />
</h:commandLink>
</f:facet>
<h:outputText value="#{item.activityStart}" />
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="Activity End Time" actionListener="#{SessionsController.sort}">
<f:attribute name="sortField" value="Activity End Time" />
</h:commandLink>
</f:facet>
<h:outputText value="#{item.activityEnd}" />
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="Activity" actionListener="#{SessionsController.sort}">
<f:attribute name="sortField" value="Activity" />
</h:commandLink>
</f:facet>
<h:outputText value="#{item.activity}" />
</h:column>
</h:dataTable>
<!-- The paging buttons -->
<h:commandButton value="first" action="#{SessionsController.pageFirst}"
disabled="#{SessionsController.firstRow == 0}" />
<h:commandButton value="prev" action="#{SessionsController.pagePrevious}"
disabled="#{SessionsController.firstRow == 0}" />
<h:commandButton value="next" action="#{SessionsController.pageNext}"
disabled="#{SessionsController.firstRow + SessionsController.rowsPerPage >= SessionsController.totalRows}" />
<h:commandButton value="last" action="#{SessionsController.pageLast}"
disabled="#{SessionsController.firstRow + SessionsController.rowsPerPage >= SessionsController.totalRows}" />
<h:outputText value="Page #{SessionsController.currentPage}/#{SessionsController.totalPages}" />
<br />
<!-- The paging links -->
<ui:repeat value="#{SessionsController.pages}" var="page">
<h:commandLink value="#{page}" actionListener="#{SessionsController.page}"
rendered="#{page != SessionsController.currentPage}" />
<h:outputText value="#{page}" escape="false"
rendered="#{page == SessionsController.currentPage}" />
</ui:repeat>
<br />
<!-- Set rows per page -->
<h:outputLabel for="rowsPerPage" value="Rows per page" />
<h:inputText id="rowsPerPage" value="#{SessionsController.rowsPerPage}" size="3" maxlength="3" />
<h:commandButton value="Set" action="#{SessionsController.pageFirst}" />
<h:message for="rowsPerPage" errorStyle="color: red;" />
</h:form>
</div>
<div id="settingsdiva" style="width:350px; height:400px; position:absolute; background-color:transparent; top:20px; left:400px">
</div>
<div id="settingsdivb" style="width:350px; height:400px; position:absolute; background-color:transparent; top:20px; left:800px">
</div>
</div>
</div>
</h:body>
</html>
Sessions:
import java.io.Serializable;
import javax.enterprise.context.SessionScoped;
// or import javax.faces.bean.SessionScoped;
import javax.inject.Named;
/* include SQL Packages */
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import javax.annotation.Resource;
import javax.faces.bean.ViewScoped;
import javax.faces.component.UICommand;
import javax.faces.context.FacesContext;
import javax.inject.Inject;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
// or import javax.faces.bean.ManagedBean;
import javax.faces.event.ActionEvent;
import org.glassfish.osgicdi.OSGiService;
// source http://balusc.blogspot.com/2008/10/effective-datatable-paging-and-sorting.html
@Named("SessionsController")
@ViewScoped
public class Sessions implements Serializable {
/* Call the Oracle JDBC Connection driver */
@Resource(name = "jdbc/Oracle")
private DataSource ds;
// Data.
private List<ActiveSessionObj> dataList;
// Rows
private int totalRows;
// Paging.
private int firstRow;
private int rowsPerPage;
private int totalPages;
private int pageRange;
private Integer[] pages;
private int currentPage;
// Sorting.
private String sortField;
private boolean sortAscending;
/* Constructor */
public Sessions() {
/* Set default properties */
rowsPerPage = 10; // Default rows per page (max amount of rows to be displayed at once).
pageRange = 10; // Default page range (max amount of page links to be displayed at once).
sortField = "ASESSIONID"; // Default sort field.
sortAscending = true; // Default sort direction.
}
public static class ActiveSessionObj {
/* Oracle table structure
CREATE TABLE ACTIVESESSIONSLOG(
ASESSIONID VARCHAR2(30) NOT NULL,
USERID VARCHAR2(30),
ACTIVITYSTART TIMESTAMP(6),
ACTIVITYEND TIMESTAMP(6),
ACTIVITY CLOB
)
*/
private String aSessionID;
private String userID;
private Date activityStart;
private Date activityEnd;
private String activity;
public ActiveSessionObj(String aSessionID, String userID, Date activityStart, Date activityEnd, String activity) {
this.aSessionID = aSessionID;
this.userID = userID;
this.activityStart = activityStart;
this.activityEnd = activityEnd;
this.activity = activity;
}
public String getaSessionID() {
return aSessionID;
}
public void setaSessionID(String aSessionID) {
this.aSessionID = aSessionID;
}
public String getactivity() {
return activity;
}
public void setactivity(String activity) {
this.activity = activity;
}
public Date getactivityEnd() {
return activityEnd;
}
public void setactivityEnd(Date activityEnd) {
this.activityEnd = activityEnd;
}
public Date getactivityStart() {
return activityStart;
}
public void setactivityStart(Date activityStart) {
this.activityStart = activityStart;
}
public String getuserID() {
return userID;
}
public void setuserID(String userID) {
this.userID = userID;
}
private ActiveSessionObj() {
throw new UnsupportedOperationException("Not yet implemented");
}
}
// Paging actions -----------------------------------------------------------------------------
public void pageFirst() {
page(0);
}
public void pageNext() {
page(firstRow + rowsPerPage);
}
public void pagePrevious() {
page(firstRow - rowsPerPage);
}
public void pageLast() {
page(totalRows - ((totalRows % rowsPerPage != 0) ? totalRows % rowsPerPage : rowsPerPage));
}
public void page(ActionEvent event) {
page(((Integer) ((UICommand) event.getComponent()).getValue() - 1) * rowsPerPage);
}
private void page(int firstRow) {
this.firstRow = firstRow;
loadDataList(); // Load requested page.
}
// Sorting actions ----------------------------------------------------------------------------
public void sort(ActionEvent event) {
String sortFieldAttribute = (String) event.getComponent().getAttributes().get("sortField");
// If the same field is sorted, then reverse order, else sort the new field ascending.
if (sortField.equals(sortFieldAttribute)) {
sortAscending = !sortAscending;
} else {
sortField = sortFieldAttribute;
sortAscending = true;
}
pageFirst(); // Go to first page and load requested page.
}
// Loaders ------------------------------------------------------------------------------------
private void loadDataList() {
// Load list and totalCount.
try {
dataList = list(firstRow, rowsPerPage, sortField, sortAscending);
totalRows = countDBRowNum(); //count the tablerows
} catch (Exception e) {
throw new RuntimeException(e);
}
// Set currentPage, totalPages and pages.
currentPage = (totalRows/rowsPerPage) - ((totalRows - firstRow)/rowsPerPage) + 1;
totalPages = (totalRows/rowsPerPage) + ((totalRows % rowsPerPage != 0) ? 1 : 0);
int pagesLength = Math.min(pageRange, totalPages);
pages = new Integer[pagesLength];
// firstPage must be greater than 0 and lesser than totalPages-pageLength.
int firstPage = Math.min(Math.max(0, currentPage - (pageRange/2)), totalPages - pagesLength);
// Create pages (page numbers for page links).
for (int i = 0; i < pagesLength; i++) {
pages[i] = ++firstPage;
}
}
// Getters ------------------------------------------------------------------------------------
public List<ActiveSessionObj> getdataList() {
if (dataList == null) {
loadDataList(); // Preload page for the 1st view.
}
return dataList;
}
public int getTotalRows() {
return totalRows;
}
public int getFirstRow() {
return firstRow;
}
public int getRowsPerPage() {
return rowsPerPage;
}
public Integer[] getPages() {
return pages;
}
public int getCurrentPage() {
return currentPage;
}
public int getTotalPages() {
return totalPages;
}
// Setters ------------------------------------------------------------------------------------
public void setRowsPerPage(int rowsPerPage) {
this.rowsPerPage = rowsPerPage;
}
// Actions ------------------------------------------------------------------------------------
/**
* Returns list of ActiveSessionObj items starting at the given first index with the given row count,
* sorted by the given sort field and sort order.
* @param firstRow First index of rows to be returned.
* @param rowCount Amount of rows to be returned.
* @param sortField Field to sort the data on.
* @param sortAscending Whether to sort data ascending or not.
* @return list of ActiveSessionObj items starting at the given first index with the given row count,
* sorted by the given sort field and sort order.
* @throws DAOException If something fails at DAO level.
*/
public List<ActiveSessionObj> list(int firstRow, int rowCount, String sortField, boolean sortAscending) throws SQLException {
String SqlStatement = null;
if (ds == null) {
throw new SQLException();
}
Connection conn = ds.getConnection();
if (conn == null) {
throw new SQLException();
}
String sortDirection = sortAscending ? "ASC" : "DESC";
SqlStatement = "SELECT c.*" +
" FROM (SELECT b.*, rownum rn" +
" FROM (SELECT a.*" +
" FROM activeSessionsLog a" +
" ORDER BY %s %s) b" +
" WHERE rownum <= ?) c" +
" WHERE rn >= ?";
String sql = String.format(SqlStatement, sortField, sortDirection);
PreparedStatement ps = null;
ResultSet resultSet = null;
List<ActiveSessionObj> dataList = new ArrayList<ActiveSessionObj>();
try {
conn.setAutoCommit(false);
boolean committed = false;
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, firstRow);
ps.setInt(2, rowCount);
resultSet = ps.executeQuery();
/* take the result from the SQL query and insert it into Array List collection */
dataList = ActiveSessionsArrayList(resultSet);
conn.commit();
committed = true;
} finally {
if (!committed) {
conn.rollback();
}
}
} finally {
ps.close();
conn.close();
}
return dataList;
}
/**
* Returns total amount of rows in table.
* @return Total amount of rows in table.
* @throws DAOException If something fails at DAO level.
*/
public int countDBRowNum() throws Exception {
String SqlStatement = null;
if (ds == null) {
throw new SQLException();
}
Connection conn = ds.getConnection();
if (conn == null) {
throw new SQLException();
}
SqlStatement = "SELECT count(*) FROM ACTIVESESSIONSLOG";
PreparedStatement ps = null;
ResultSet resultSet = null;
int count = 0;
try {
conn.setAutoCommit(false);
boolean committed = false;
try {
SqlStatement = "SELECT count(*) FROM ACTIVESESSIONSLOG";
ps = conn.prepareStatement(SqlStatement);
resultSet = ps.executeQuery();
if (resultSet.next()) {
count = resultSet.getInt(1);
}
conn.commit();
committed = true;
} finally {
if (!committed) {
conn.rollback();
}
}
} finally {
ps.close();
conn.close();
}
return count;
}
/**
* Map the current row of the given ResultSet to ActiveSessionObj.
* @param resultSet The ResultSet of which the current row is to be mapped to ActiveSessionObj.
* @return The mapped ActiveSessionObj from the current row of the given ResultSet.
* @throws SQLException If something fails at database level.
*/
private static ArrayList<ActiveSessionObj> ActiveSessionsArrayList(ResultSet rs) throws SQLException {
ArrayList<ActiveSessionObj> list = new ArrayList<>();
try {
while (rs.next()) {
list.add(new ActiveSessionObj(
rs.getString("ASESSIONID"),
rs.getString("USERID"),
timestampToDate(rs.getTimestamp("ACTIVITYSTART")),
timestampToDate(rs.getTimestamp("ACTIVITYEND")),
rs.getString("ACTIVITY")));
}
} catch (Exception x) {
x.printStackTrace();
}
return list;
/*
CREATE TABLE ACTIVESESSIONSLOG(
ASESSIONID VARCHAR2(30) NOT NULL,
USERID VARCHAR2(30),
ACTIVITYSTART TIMESTAMP(6),
ACTIVITYEND TIMESTAMP(6),
ACTIVITY CLOB
)
*/
}
// select all button handle
private Map<Long, Boolean> selectedIds = new HashMap<Long, Boolean>();
// get the list from the JSF page
public Map<Long, Boolean> getSelectedIds() {
return selectedIds;
}
// call this method from the JSF page to delete the selected rows
public String deleteAction() {
// do something with the selected rows
return null;
}
private static Date timestampToDate(java.sql.Timestamp ts) {
Date d = null;
try {
d = new Date(ts.getTime());
} catch (Exception e) {
e.printStackTrace();
}
return d;
}
}
Có lẽ thuật toán pagination là sai hoặc truy vấn SQL là uncorrected? Tôi chưa chạm vào thuật toán phân trang từ mã gốc.
nhất Wishes
truy vấn EDIT
SQL là sai.
CHỈNH SỬA 2 Tôi đã cập nhật mã SQL nhưng bây giờ trang đầu tiên là sai và thứ hai và vv hiển thị dữ liệu. Vấn đề là ở đây đâu đó:
EDIT 3 Mã làm việc
public List danh sách (int firstRow, int rowCount, String sortField, boolean sortAscending) throws SQLException {
String SqlStatement = null;
if (ds == null) {
throw new SQLException();
}
Connection conn = ds.getConnection();
if (conn == null) {
throw new SQLException();
}
int countrow = firstRow + rowCount;
String sortDirection = sortAscending ? "ASC" : "DESC";
SqlStatement = "SELECT c.*" +
" FROM (SELECT b.*, rownum rn" +
" FROM (SELECT a.*" +
" FROM activeSessionsLog a" +
" ORDER BY %s %s) b" +
" WHERE rownum <= ?) c" +
" WHERE rn > ?";
String sql = String.format(SqlStatement, sortField, sortDirection);
PreparedStatement ps = null;
ResultSet resultSet = null;
List<ActiveSessionObj> dataList = new ArrayList<ActiveSessionObj>();
try {
conn.setAutoCommit(false);
boolean committed = false;
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, countrow);
ps.setInt(2, firstRow);
resultSet = ps.executeQuery();
/* take the result from the SQL query and insert it into Array List collection */
dataList = ActiveSessionsArrayList(resultSet);
conn.commit();
committed = true;
} finally {
if (!committed) {
conn.rollback();
}
}
} finally {
ps.close();
conn.close();
}
return dataList;
}
Cảm ơn bạn! Với sự giúp đỡ của bạn, tôi đã tìm ra giải pháp. Bây giờ nó hoạt động. Bằng cách này bạn có thể đề xuất tôi làm thế nào tôi có thể làm giảm mã mà tính toán các pagination? P.S hệ thống nói rằng tôi có thể cung cấp cho bạn các điểm sau 23 giờ. –
Chúng tôi sử dụng các khuôn mặt chính làm thư viện JSF, nó cung cấp một phương pháp đơn giản để phân trang, bạn có thể xem ví dụ tại đây http://www.primefaces.org/showcase/ui/datatablePagination.jsf – Teg
Có, nhưng tôi cần triển khai tải chậm và tôi cần kiểm soát nhiều hơn mã vì tôi cần thực hiện tùy chỉnh tốt. Tôi thích viết mã nguồn gốc. –