页面:
<f:view>
<h:form id="formlist">
<rich:dataTable id="carList" width="483" columnClasses="col" rows="10"
value="#{testBean.dataModel}" var="car">
<f:facet name="header">
<rich:columnGroup>
<h:column>
<h:outputText styleClass="headerText" value="Name" />
</h:column>
<h:column>
<h:outputText styleClass="headerText" value="Decription" />
</h:column>
<h:column>
<h:outputText styleClass="headerText" value="Base Price" />
</h:column>
<h:column>
<h:outputText styleClass="headerText" value="Time" />
</h:column>
<h:column>
<h:outputText styleClass="headerText" value="操作" />
</h:column>
</rich:columnGroup>
</f:facet>
<h:column>
<h:outputText value="#{car.name}" />
</h:column>
<h:column>
<h:outputText value="#{car.description}" />
</h:column>
<h:column>
<h:outputText value="#{car.baseprice}" />
</h:column>
<h:column>
<h:outputText value="#{car.timestamp}" />
</h:column>
<h:column>
<h:commandLink action="#{user.delete}" value="删除" >
<f:param name="id" value="#{car.id}"/>
</h:commandLink>
</h:column>
</rich:dataTable>
<rich:datascroller for="carList" id="dc1"
style="width:483px" page="#{user.scrollerPage}"/>
</h:form>
</f:view>
DataPage.java:
package com.jsecode.util.pagination;
import java.util.List;
public class DataPage
{
/** *//**
* 将需要的页的数据封装到一个DataPage中去， 这个类表示了我们需要的一页的数据，<br>
* 里面包含有三个元素：datasetSize，startRow，和一个用于表示具体数据的List。<br>
* datasetSize表示了这个记录集的总条数，查询数据的时候，使用同样的条件取count即可，<br>
* startRow表示该页的起始行在数据库中所有记录集中的位置
*/
private int datasetSize;
private int startRow;
private List data;
/** *//**
*
* @param datasetSize
* 数据集大小
* @param startRow
* 起始行
* @param data
* 数据list
*/
public DataPage(int datasetSize, int startRow, List data)
{
this.datasetSize = datasetSize;
this.startRow = startRow;
this.data = data;
}
/** *//**
*
* @return
*/
public int getDatasetSize()
{
return datasetSize;
}
public int getStartRow()
{
return startRow;
}
/** *//**
*
* @return 已填充好的数据集
*/
public List getData()
{
return data;
}
}
PagedListDataModel.java:
package com.jsecode.util.pagination;
import javax.faces.model.DataModel;
public abstract class PagedListDataModel extends DataModel {
int pageSize;
int rowIndex;
DataPage page;
/** *//**
* Create a datamodel that pages through the data showing the specified
* number of rows on each page.
*/
public PagedListDataModel(int pageSize) {
super();
this.pageSize = pageSize;
this.rowIndex = -1;
this.page = null;
}
/** *//**
* Not used in this class; data is fetched via a callback to the fetchData
* method rather than by explicitly assigning a list.
*/
public void setWrappedData(Object o) {
if (o instanceof DataPage) {
this.page = (DataPage) o;
} else {
throw new UnsupportedOperationException(" setWrappedData ");
}
}
public int getRowIndex() {
return rowIndex;
}
/** *//**
* Specify what the "current row" within the dataset is. Note that the
* UIData component will repeatedly call this method followed by getRowData
* to obtain the objects to render in the table.
*/
public void setRowIndex(int index) {
rowIndex = index;
}
/** *//**
* Return the total number of rows of data available (not just the number of
* rows in the current page!).
*/
public int getRowCount() {
return getPage().getDatasetSize();
}
/** *//**
* Return a DataPage object; if one is not currently available then fetch
* one. Note that this doesn't ensure that the datapage returned includes
* the current rowIndex row; see getRowData.
*/
private DataPage getPage() {
if (page != null) {
return page;
}
int rowIndex = getRowIndex();
int startRow = rowIndex;
if (rowIndex == -1) {
// even when no row is selected, we still need a page
// object so that we know the amount of data available.
startRow = 0;
} // invoke method on enclosing class
page = fetchPage(startRow, pageSize);
return page;
}
/** *//**
* Return the object corresponding to the current rowIndex. If the DataPage
* object currently cached doesn't include that index then fetchPage is
* called to retrieve the appropriate page.
*/
public Object getRowData() {
if (rowIndex < 0) {
throw new IllegalArgumentException(
" Invalid rowIndex for PagedListDataModel; not within page ");
} // ensure page exists; if rowIndex is beyond dataset size, then
// we should still get back a DataPage object with the dataset size
// in it
if (page == null) {
page = fetchPage(rowIndex, pageSize);
}
int datasetSize = page.getDatasetSize();
int startRow = page.getStartRow();
int nRows = page.getData().size();
int endRow = startRow + nRows;
if (rowIndex >= datasetSize) {
throw new IllegalArgumentException(" Invalid rowIndex ");
}
if (rowIndex < startRow) {
page = fetchPage(rowIndex, pageSize);
startRow = page.getStartRow();
} else if (rowIndex >= endRow) {
page = fetchPage(rowIndex, pageSize);
startRow = page.getStartRow();
}
return page.getData().get(rowIndex - startRow);
}
public Object getWrappedData() {
return page.getData();
}
/** *//**
* Return true if the rowIndex value is currently set to a value that
* matches some element in the dataset. Note that it may match a row that is
* not in the currently cached DataPage; if so then when getRowData is
* called the required DataPage will be fetched by calling fetchData.
*/
public boolean isRowAvailable() {
DataPage page = getPage();
if (page == null) {
return false;
}
int rowIndex = getRowIndex();
if (rowIndex < 0) {
return false;
} else if (rowIndex >= page.getDatasetSize()) {
return false;
} else {
return true;
}
}
/** *//**
* Method which must be implemented in cooperation with the managed bean
* class to fetch data on demand.
*/
public abstract DataPage fetchPage(int startRow, int pageSize);
/** *//**
* 添加了刷新模块
*/
public void reflash() {
if (this.page != null) {
this.page = null;
getPage();
}
}
}
TestBean.java:被datatable调用的类
public class TestBean
{
//不同的分页需求需要添加不同的dataModel，并实现不同的getDataModel
//例如，需要获得有名称条件的分页可以定义dataModelName,和getDataModelName()实现
private DataModel dataModel;
public DataModel getDataModel()
{
if ( dataModel == null ) {
dataModel = new PagedListDataModel(10)
{
/** *//**
* 用不同的条件获得数据集和数量
*/
public DataPage fetchPage(int startRow, int pageSize)
{
// call enclosing managed bean method to fetch the data
CarBeanDAO dao = new CarBeanDAO();
String sql = "from CarBean model order by model.id desc";
Query query = EntityManagerHelper.createQuery(sql);
query.setFirstResult(startRow);
query.setMaxResults(pageSize);
List list = query.getResultList();
System.out.println("current row count = " + list.size());
Query q = EntityManagerHelper.createQuery("select count(*) from CarBean");
return new DataPage(Integer.parseInt(q.getSingleResult().toString()), startRow, list);
}
};
}
return dataModel;
}
}
配置文件：
<managed-bean>
<managed-bean-name>testBean</managed-bean-name>
<managed-bean-class>com.jsecode.util.pagination.TestBean</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
有人反映会出现获取两次DataModel的情况,为什么呢？
经过我的测试，是因为设置的datatable的rows属性的值大于了程序中pageSize的值，比如你设置rows="12"，而你的pageSize设置的是10，那么JSF为了满足显示12条得条件，就会取两次数据集组成一个12跳得数据集显示出来。
posted on 2008-11-23 00:53
Vincent-chen 阅读(871)
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