自定义Lazy Model分页异常求助：首次进入页面分页按钮未启用

使用自定义Lazy Model时遇到以下问题：首次进入xhtml页面，分页按钮处于未启用状态；但对案件列排序后，分页功能恢复正常。数据通过原生查询提取，数据本身无问题，不清楚未排序时分页失效的原因，需要解决。

XHTML代码 #

<p:dataTable var="expediente"
             value="#{peticionesPendientesBean.lazyModel}"
             rowKey="#{expediente.mCodExpediente}"
             sortBy="#{expediente.t1.id_expediente}" sortOrder="UNSORTED" paginator="true"                                           
             rows="10"
             styleClass="desplegable"
             paginatorTemplate="{CurrentPageReport} 0 Seleccionados {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown} "
             rowsPerPageTemplate="10,20,50,100,200"
             id="tblPendientes" lazy="true" emptyMessage="#{msg.tbl_noRegist}"
             currentPageReportTemplate="#{peticionesPendientesBean.lazyModel.rowCount==1? lbl.tb_exp_pag : lbl.tb_exps_pag}">                                       
                                    
    <p:column headerText="#{lbl.titulo_peticiones_pendientes}"
              sortBy="#{expediente.id_expediente}" id="codExpediente">
        <h:outputText value="#{expediente.getAtributo(nombreAtributos.CODEXPEDIENTE).value} " />
    </p:column>

Java代码（LazyModel的load方法） #

/**
 * @param first
 * @param pageSize
 * @param sortField
 * @param sortOrder
 * @param filters
 */
@Override
public List<Expediente> load(int first, int pageSize, String sortField, SortOrder sortOrder,
        Map<String, Object> filters) {

    try {
        System.out.println("usuario" + user.getCentroDirectivo().getCodCentro());
        System.out.println("perfil" + user.getRole());
        System.out.println("peticionesPendientes: " + peticionesPendientes);
        System.out.println("user: " + user);

        if (sortField == null || sortOrder.equals(SortOrder.UNSORTED)) {
            sortField = "id_expediente"; 
            sortOrder = SortOrder.DESCENDING;
        }

        this.dataSource = this.peticionesPendientes.buscarPendientesNativa(user.getCentroDirectivo().getCodCentro(),
                user.getRole(), first, pageSize, sortField, sortOrder);
        System.out.println("datasource" + dataSource.size());
        
        int count = portaFirmaEnvios.buscarPendientesNativaCount(user.getCentroDirectivo().getCodCentro(),
                user.getRole());
        if (count == 0) {
            this.setRowCount(0);
        } else {
            this.setRowCount(count);
        }
        
    } catch (final Exception e) {
        final FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(Cadenas.EVENT,
                new FacesMessage(FacesMessage.SEVERITY_ERROR, Presentacion.ERROR_MSG, ERR.getString("error_con_motor")));
        dataSource = new ArrayList<Expediente>();
        this.setRowCount(dataSource.size());

        logger.log(Level.SEVERE, e.getMessage() + e.getCause(), e);
    }
    return dataSource;
}

问题根源分析 #

1. 初始排序状态冲突：xhtml中dataTable设置了sortOrder="UNSORTED"，但load方法里手动替换了排序规则，PrimeFaces组件初始化时可能因为状态不匹配，导致分页组件未正确识别总记录数，从而禁用按钮。排序操作触发后，组件重新调用load，此时状态同步，分页功能恢复。
2. rowCount初始化时机滞后：总记录数仅在load方法中设置，而组件初始化时可能未及时获取到该值，分页按钮因无法判断总页数而保持禁用。

解决方案 #

方案1：移除xhtml的初始排序配置 #

让LazyModel完全控制初始排序逻辑，去掉dataTable上的sortBy和sortOrder属性：

<p:dataTable var="expediente"
             value="#{peticionesPendientesBean.lazyModel}"
             rowKey="#{expediente.mCodExpediente}"
             paginator="true"                                           
             rows="10"
             styleClass="desplegable"
             paginatorTemplate="{CurrentPageReport} 0 Seleccionados {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown} "
             rowsPerPageTemplate="10,20,50,100,200"
             id="tblPendientes" lazy="true" emptyMessage="#{msg.tbl_noRegist}"
             currentPageReportTemplate="#{peticionesPendientesBean.lazyModel.rowCount==1? lbl.tb_exp_pag : lbl.tb_exps_pag}">                                       
    <p:column headerText="#{lbl.titulo_peticiones_pendientes}"
              sortBy="#{expediente.id_expediente}" id="codExpediente">
        <h:outputText value="#{expediente.getAtributo(nombreAtributos.CODEXPEDIENTE).value} " />
    </p:column>

方案2：提前初始化rowCount #

在LazyModel的构造方法中提前获取总记录数并设置，确保组件初始化时就能拿到正确的总页数：

public class CustomLazyModel extends LazyDataModel<Expediente> {
    private PortaFirmaEnvios portaFirmaEnvios;
    private User user;

    public CustomLazyModel(User user, PortaFirmaEnvios portaFirmaEnvios) {
        this.user = user;
        this.portaFirmaEnvios = portaFirmaEnvios;
        // 初始化时获取总记录数
        try {
            int count = portaFirmaEnvios.buscarPendientesNativaCount(user.getCentroDirectivo().getCodCentro(), user.getRole());
            this.setRowCount(count);
        } catch (Exception e) {
            this.setRowCount(0);
            // 异常日志记录
        }
    }

    @Override
    public List<Expediente> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String, Object> filters) {
        try {
            if (sortField == null || sortOrder.equals(SortOrder.UNSORTED)) {
                sortField = "id_expediente"; 
                sortOrder = SortOrder.DESCENDING;
            }

            this.dataSource = this.peticionesPendientes.buscarPendientesNativa(user.getCentroDirectivo().getCodCentro(),
                    user.getRole(), first, pageSize, sortField, sortOrder);
            
        } catch (final Exception e) {
            final FacesContext context = FacesContext.getCurrentInstance();
            context.addMessage(Cadenas.EVENT,
                    new FacesMessage(FacesMessage.SEVERITY_ERROR, Presentacion.ERROR_MSG, ERR.getString("error_con_motor")));
            dataSource = new ArrayList<Expediente>();
            this.setRowCount(dataSource.size());

            logger.log(Level.SEVERE, e.getMessage() + e.getCause(), e);
        }
        return dataSource;
    }
}

方案3：手动触发初始加载 #

在页面Bean的初始化方法中，手动调用load方法，确保rowCount被提前设置：

@ManagedBean
@ViewScoped
public class PeticionesPendientesBean {
    private LazyDataModel<Expediente> lazyModel;

    @PostConstruct
    public void init() {
        lazyModel = new CustomLazyModel(user, portaFirmaEnvios);
        // 手动触发初始加载，同步状态
        lazyModel.load(0, 10, null, SortOrder.UNSORTED, new HashMap<>());
    }
}

验证要点 #

• 检查控制台输出的rowCount值，确认首次加载时总记录数已正确设置。
• 验证buscarPendientesNativaCount方法返回的总记录数准确，无过滤条件错误。

内容的提问来源于stack exchange，提问作者Liliymas