在 Java 中使用 Supplier<InputStream> 流给出 Jersey 响应

Question

所以我现在的处境很糟糕。我有一个包含方法 "getAllData" 的 class 修订版。该方法 return 是 InputStream 的供应商。

public class Revision {
    private String id;
    private Supplier<InputStream> allData;

    public Revision(String id, Supplier<InputStream> allData) {
        this.id = id;
        this.allData = allData;
    }

    public getAllData() {
        return allData;
    }
}

假设我有 2 次修订。它们是这样声明的：

Supplier<InputStream> revisionValue1 = () -> new ByteArrayInputStream(
            "{\"name\":\"George\", \"state\":\"Colorado\", \"Exp\":\"lots\"}".getBytes());
Revision revision1 = new Revision("Id1", revisionValue1);

Supplier<InputStream> revisionValue2 = () -> new ByteArrayInputStream(
            "{\"name\":\"Sean\", \"state\":\"New York\"}".getBytes());
Revision revision2 = new Revision("Id2", revisionValue2);

然后将它们放入地图成员中：

Map<String, Revision> revisions = new HashMap<>();
revisions.put("Id1", revision1);
revisions.put("Id2", revision2);

一个当前的方法（它本身可能写得不是很好）return一个流：

public Stream<Revision> getRevisions() {
    return revisions.values().stream();
}

现在在我的 Jersey 代码中，我需要弄清楚如何 return 这些值作为 Json 格式的响应。所以结果应该类似于：

[
{
    "name": "George",
    "state": "Colorado",
    "Exp": "lots"
},
{
    "name": "Sean",
    "state": "New York"
}
]

我正在尝试以纯文本格式执行此操作，但无法正常工作。我正在尝试的是：

@Produces(MediaType.TEXT_PLAIN)
public Response getRevisions(...) {

    Stream<Revision> revisionObjects = getRevisions();

    // each Revision option has a getAllData() method that needs called, which returns Supplier<InputStream>
    // each Supplier<InputStream> contains, essentially, a Json record

    // attempt at creating a StreamingOutput that can be sent as a response
    if (revisionObjects != null) {
        StreamingOutput stream = os -> {
            Writer writer = new OutputStreamWriter(os);
            Iterator<Revision> revisionIterator = revisionObjects.iterator();
            while (revisionIterator.hasNext()) {
                Revision next = revisionIterator.next();
                writer.write(next.getAllData().get().toString());
            }
            writer.flush();
        };
        return Response.ok(stream).build();
    }
    return Response.noContent().build();
}

这是 return 结果如下：

java.io.ByteArrayInputStream@7de636java.io.ByteArrayInputStream@ba0b09

我假设这是因为在作者的 "toString()" 方法之前需要一个额外的步骤。

抱歉，这有多长，我只是想提供详细信息。有谁知道如何让它工作？理想情况下，我希望它以 JSON 响应，但即使是纯文本也会有很大的进步。

P.S。我仍在努力思考 InputStreams 和 OutputStreams，所以很可能，我有一些不合逻辑的东西。

Answer 1

@Produces(MediaType.TEXT_PLAIN)
public Response getRevisions(...) {

    Stream<Revision> revisionObjects = getRevisions();

    // each Revision option has a getAllData() method that needs called, which returns Supplier<InputStream>
    // each Supplier<InputStream> contains, essentially, a Json record

    // attempt at creating a StreamingOutput that can be sent as a response
    if (revisionObjects != null) {
            Iterator<Revision> revisionIterator = revisionObjects.iterator();
            List<JSONObject> revisionsResponse = new ArrayList<JSONObject>();
            while (revisionIterator.hasNext()) {
                BufferedReader streamReader = new BufferedReader(new InputStreamReader(revisionIterator.next().getAllData().get(), "UTF-8")); 
                StringBuilder responseStrBuilder = new StringBuilder();

                String inputStr;
                while ((inputStr = streamReader.readLine()) != null)
                        responseStrBuilder.append(inputStr);
                revisionsResponse.add(new JSONObject(responseStrBuilder.toString());
            }

            return Response.ok(revisionsResponse).build();
    }
    return Response.noContent().build();
}

在 Java 中使用 Supplier<InputStream> 流给出 Jersey 响应

Give a Jersey response using a Stream of Supplier<InputStream> in Java

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