8

我刚刚在“ DataTable - Lazy Loading ”的展示代码中启用了多重排序

datatableLazy.xhtml

<html lang="en" xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:ui="http://java.sun.com/jsf/facelets">
<h:head>
<title>CarDataTable</title>
</h:head>
<h:body>
<h:form id="form">
    <p:dataTable var="car" value="#{tableBean.lazyModel}" paginator="true"
        rows="10"
        paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
        rowsPerPageTemplate="5,10,15" id="carTable" lazy="true"
        sortMode="multiple">

        <p:ajax event="rowSelect" listener="#{tableBean.onRowSelect}"
            update=":form:display" oncomplete="carDialog.show()" />

        <p:column headerText="Model" sortBy="#{car.model}"
            filterBy="#{car.model}">
            <h:outputText value="#{car.model}" />
        </p:column>

        <p:column headerText="Year" sortBy="#{car.year}"
            filterBy="#{car.year}">
            <h:outputText value="#{car.year}" />
        </p:column>

        <p:column headerText="Manufacturer" sortBy="#{car.manufacturer}"
            filterBy="#{car.manufacturer}">
            <h:outputText value="#{car.manufacturer}" />
        </p:column>

        <p:column headerText="Color" sortBy="#{car.color}"
            filterBy="#{car.color}">
            <h:outputText value="#{car.color}" />
        </p:column>
    </p:dataTable>
</h:form>
</h:body>
</html>

TableBean.java

package com.solartis.primefaces.sample;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import javax.faces.bean.ManagedBean;

import org.primefaces.model.LazyDataModel;

@ManagedBean
public class TableBean {

private LazyDataModel<Car> lazyModel;

private Car selectedCar;

private List<Car> cars = new ArrayList<Car>();

private final static String[] colors;

private final static String[] manufacturers;

static {
    colors = new String[10];
    colors[0] = "Black";
    colors[1] = "White";
    colors[2] = "Green";
    colors[3] = "Red";
    colors[4] = "Blue";
    colors[5] = "Orange";
    colors[6] = "Silver";
    colors[7] = "Yellow";
    colors[8] = "Brown";
    colors[9] = "Maroon";

    manufacturers = new String[10];
    manufacturers[0] = "Mercedes";
    manufacturers[1] = "BMW";
    manufacturers[2] = "Volvo";
    manufacturers[3] = "Audi";
    manufacturers[4] = "Renault";
    manufacturers[5] = "Opel";
    manufacturers[6] = "Volkswagen";
    manufacturers[7] = "Chrysler";
    manufacturers[8] = "Ferrari";
    manufacturers[9] = "Ford";
}

public TableBean() {
    populateRandomCars(cars, 50);
    lazyModel = new LazyCarDataModel(cars);
}

public Car getSelectedCar() {
    return selectedCar;
}

public void setSelectedCar(Car selectedCar) {
    this.selectedCar = selectedCar;
}

public LazyDataModel<Car> getLazyModel() {
    return lazyModel;
}

private void populateRandomCars(List<Car> list, int size) {
    for (int i = 0; i < size; i++) {
        list.add(new Car(getRandomModel(), getRandomYear(),
                getRandomManufacturer(), getRandomColor()));
    }
}

private String getRandomColor() {
    return colors[(int) (Math.random() * 10)];
}

private String getRandomManufacturer() {
    return manufacturers[(int) (Math.random() * 10)];
}

private int getRandomYear() {
    return (int) (Math.random() * 50 + 1960);
}

private String getRandomModel() {
    return UUID.randomUUID().toString().substring(0, 8);
}
}

LazyCarDataModel.java

package com.solartis.primefaces.sample;

import java.util.ArrayList;

/**
 * Dummy implementation of LazyDataModel that uses a list to mimic a real 
   datasource like a database.
 */
public class LazyCarDataModel extends LazyDataModel<Car> {

private List<Car> datasource;

public LazyCarDataModel(List<Car> datasource) {
    this.datasource = datasource;
}

@Override
public Car getRowData(String rowKey) {
    for(Car car : datasource) {
        if(car.getModel().equals(rowKey))
            return car;
    }

    return null;
}

@Override
public void setRowIndex(int rowIndex) {

    if (rowIndex == -1 || getPageSize() == 0) {
        super.setRowIndex(-1);
    } else
        super.setRowIndex(rowIndex % getPageSize());
}

@Override
public Object getRowKey(Car car) {
    return car.getModel();
}

@Override
public List<Car> load(int first, int pageSize, 
                      List<SortMeta> multiSortMeta,Map<String, String> filters) {

    System.out.println("\nTHE INPUT PARAMETER VALUE OF LOAD METHOD :   
    \t"+"first=" + first + ", pagesize=" + pageSize + ", multiSortMeta=" + 
    multiSortMeta + " filter:" + filters);

    System.out.println("\nTHE MULTISORTMETA CONTENT  : \t");

    if (multiSortMeta != null) {
        for (SortMeta sortMeta : multiSortMeta) {
            System.out.println("SORTFIELD:" +sortMeta.getSortField());
            System.out.println("SORTORDER:" +sortMeta.getSortOrder());
                    System.out.println("SORTFUNCTION:"
                                                         +sortMeta.getSortFunction());
            System.out.println("COLUMN:" +sortMeta.getColumn());
            System.out.println("CLASS:" +sortMeta.getClass());
        }
    }

    List<Car> data = new ArrayList<Car>();

    //filter
    for(Car car : datasource) {
        boolean match = true;

        for(Iterator<String> it = filters.keySet().iterator(); it.hasNext();) {
            try {
                String filterProperty = it.next();
                String filterValue = filters.get(filterProperty);
                String fieldValue =  String.valueOf(car.getClass().
                                getField(filterProperty).get(car));

                if(filterValue == null || fieldValue.startsWith(filterValue)) {
                    match = true;
                }
                else {
                    match = false;
                    break;
                }
            } catch(Exception e) {
                match = false;
            } 
        }

        if(match) {
            data.add(car);
        }
    }


    //rowCount
    int dataSize = data.size();
    this.setRowCount(dataSize);

    //paginate
    if(dataSize > pageSize) {
        try {
            return data.subList(first, first + pageSize);
        }
        catch(IndexOutOfBoundsException e) {
            return data.subList(first, first + (dataSize % pageSize));
        }
    }
    else {
        return data;
    }
}
}

它工作得很好，除了当我对多列排序进行分页时，该load()方法List<SortMeta>不会给我当前排序的列详细信息以转移到其他页面，这与提供这些排序详细信息的load()方法不同。String sortField, SortOrder sortOrder

例如：

  1. 单击“制造商”中的排序箭头，然后Ctrl+单击“年份”的排序箭头

    • 您将获得该load()方法的排序列详细信息（我已经在加载方法中打印了输入参数值）。

  2. 现在，做分页。这里的load()方法未能给出排序列的详细信息

    • 不仅是分页，如果在点击排序列后输入列过滤值，同样的问题存在

我怎样才能解决这个问题？

4

2 回答 2

2

我以临时方式解决了这个问题......有一个用于存储排序列详细信息的会话范围托管 bean，以便在分页期间进入 load()，例如：-

@ManagedBean
@SessionScoped

public class StoreSortColumnDetail implements Serializable{


    /** holds multisort values**/
private List<SortMeta> mMultiSortMeta;


public List<SortMeta> getMultiSortMeta() {
    return mMultiSortMeta;
}

public void setMultiSortMeta(List<SortMeta> multiSortMeta) {
    mMultiSortMeta = multiSortMeta;
}

public void clearMultiSortMeta() {
    if(this.mMultiSortMeta != null)
        this.mMultiSortMeta.clear();

}
}

并像这样在 load() 中使用它：

@Override
public List<Car> load(int first, int pageSize, 
                  List<SortMeta> multiSortMeta,Map<String, String> filters) {

/** Instance to the SessionScoped scoped StoreSortColumnDetail managed bean*/
@ManagedProperty(value="#{StoreSortColumnDetail }")
private StoreSortColumnDetail storeSortColumnDetail ;

public void setStoreSortColumnDetail (StoreSortColumnDetail sortColumnDetail ) {
    this.storeSortColumnDetail = sortColumnDetail ;
}

/** to hold the handled sort column detail**/
List<SortMeta> handledMultiSortMeta = new ArrayList<SortMeta>();

/*Here starts the multisortmeta handling process*/
   /** check for List<SortMeta> for null**/
if(multiSortMeta != null ) {

    /** updates StoreSortColumnDetail's List<SortMeta> with Load()'s List<SortMeta>**/
    storeSortColumnDetail.setMultiSortMeta(multiSortMeta);
    handledMultiSortMeta  = multiSortMeta;
} 
/** check for List<SortMeta> for notnull **/
else if (multiSortMeta == null) {

    /**assigns Load()'s List<SortMeta> with StoreSortColumnDetail's List<SortMeta>**/
    handledMultiSortMeta  = storeSortColumnDetail.getMultiSortMeta();
} 


   /*Now u have handled multisortmeta from load()...
     and u can process now from handledMultiSortMeta*/
}

我希望你知道我是如何处理的，如果不是亲密我...但这是一种临时方式，需要通过 primefaces 方式处理它...

于 2013-06-12T05:27:15.103 回答
0

虽然这种方法可能会奏效，但您可以轻松地将实际操作委托给您的lazyDataModel 中的 Primefaces。通过这样做，您可以使您的代码库更清晰，因为您不会有任何其他类可以操作，并且您将重用已经开发的组件（无论如何您都应该这样做）。

如果您检查了 PrimeFaces 源代码，您会发现 DataTable 对其每个功能都使用具体的类，例如过滤、排序、扩展等...对于排序 Primefaces 使用一个称为BeanPropertyComparator此类的类，它的构造函数需要某些属性，但其中大多数属性可以从sortMeta发送到loadlazyDataModel方法的属性中获取。但是，如果您想获得所需的所有属性，则需要拥有 DataTable 对象，FacesContext如果您知道相关 DataTable 的客户端 ID，则可以从中获取。

假设您在一个名为的变量中有数据表实例，activeTable您所要做的就是：

UIColumn sortColumn = sortMeta.getSortColumn()
if(sortColumn.isDynamic())
  ((DynamicColumn)sortColumn).applyStatelessModel();
//for single mode sorting
ValueExpression sortByVal = activeTable.getValueExpression("sortBy");
//multiColumn sorting 
ValueExpression sortByVal = sortColumn.getValueExpression("sortBy");
int caseSensitive = activeTable.isCaseSensitiveSort();
SortOrder order = sortMeta.getSortOrder();
MethodExpression exp = sortColumn.getSortFunction();
//pass required properties to constructor
//single mode sort
Collections.sort(filteredItems, new BeanPropertyComparator(......))
//for multi column sort use ChainedBeanPropertyComparator and add every new comparator to it than
Collections.sort(filteredItems, chainedComparator);

这样，默认情况下，您的排序将支持 primefaces 默认机制支持的任何功能，而不会牺牲安全性。

于 2015-10-20T12:17:52.387 回答