Question

所有。我是Play Framework的新手，也是一般的异步编程。我已经开始了一个新项目，并且在动作控制器中遇到了问题。据我所知，我在控制器中正确地注入了Http Context，就像这段代码中显示的github上的play-java-ebean-example项目一样：

private final ListBillGroupRepository groupRepository;
private final ListBillExtractDetailRepository extractRepository;
private final FormFactory formFactory;
private final HttpExecutionContext httpExecutionContext;

@Inject
public ListBillGroupController(FormFactory formFactory,
                               ListBillGroupRepository groupRepository,
                               ListBillExtractDetailRepository extractRepository,
                               HttpExecutionContext httpExecutionContext) {
    this.extractRepository = extractRepository;
    this.groupRepository = groupRepository;
    this.formFactory = formFactory;
    this.httpExecutionContext = httpExecutionContext;
}

我在同一个控制器中有以下操作代码似乎是问题：

public CompletionStage<Result> editGroup(Long groupId, int page, String sortBy, String order, String filter) {
    CompletableFuture<PagedList<ListBillExtractDetail>> pageFuture =
            extractRepository.page(groupId, page, 10, sortBy, order, filter).toCompletableFuture();
    CompletableFuture<List<BigDecimal>> listFuture =
            extractRepository.totals(groupId).toCompletableFuture();

    return pageFuture.thenCombine(listFuture, (list, lF) ->
            ok(views.html.extractDetailsList.render(list, groupId, sortBy, order, filter))
    ).thenApplyAsync( result ->
            result, httpExecutionContext.current());
}

执行操作时，视图将按预期返回;甚至到了向前和向后滚动记录的程度。大多数情况下，我收到以下错误：

块引用

play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[CompletionException: java.lang.RuntimeException: There is no HTTP Context available from here.]]

我从控制器操作中调用数据库存储库中的以下两个方法：

public CompletionStage<PagedList<ListBillExtractDetail>> page(Long grpId, int page, int pageSize, String sortBy, String order, String filter) {
    return supplyAsync(() ->

            ebeanServer.find(ListBillExtractDetail.class).where()
            .eq("LBWA_ID", grpId)
            .ilike("EMP_ID", "%" + filter + "%")
            .orderBy(sortBy + " " + order)
            .fetch("group")
            .setFirstRow(page * pageSize)
            .setMaxRows(pageSize)
            .findPagedList(), executionContext);
}

public CompletionStage<List<BigDecimal>> totals(Long grpId){
    return supplyAsync(() -> {
        final String sql = "SELECT SUM(\"EMP_PREM\") AS totalEmployee, SUM(\"EMPLR_CONT\") AS totalEmployer," +
                " SUM(\"ACC_PREM\") AS totalPremium FROM \"lbtable\" " +
                "WHERE \"LBID\"=" + grpId;
        SqlQuery query = Ebean.createSqlQuery(sql);
        SqlRow row = query.findOne();
        List<BigDecimal> totals = new ArrayList<>();
        totals.add(row.getBigDecimal("totalEmployee"));
        totals.add(row.getBigDecimal("totalEmployer"));
        totals.add(row.getBigDecimal("totalPremium"));
        return totals;}, executionContext) ;
}

如果有人想知道，我在此操作中的目标是通过一次数据库调用将分页数据返回到视图，同时通过第二次调用将3个单独列的总和作为money（bigdecimal）总计在表格页脚中返回。 / p>

注意：当我退出第二个调用以返回3个总计列并执行以下操作时，生成的视图没有任何问题：

public CompletionStage<Result> editGroup(Long groupId, int page, String sortBy, String order, String filter) {
    // Run a db operation in another thread (using DatabaseExecutionContext)
    return extractRepository.page(groupId, page, 10, sortBy, order, filter).thenApplyAsync(list -> {
        // This is the HTTP rendering thread context
        return ok(views.html.extractDetailsList.render(list,  groupId, sortBy, order, filter));
    }, httpExecutionContext.current());
}

我的预感是我将两个CompletableFutures合并错误，虽然我不确定它为什么偶尔起作用。任何澄清或指示都将非常感激。

播放2.6此处没有可用的HTTP上下文。行动执行时的错误

0 个答案: