如何将Elasticsarch的结果转化为Spring的REST API响应

Question

我已经用Spring开发了一个REST API条目，它在Elasticsearch中执行搜索，现在我想返回ES找到的任何结果作为响应。我不关心搜索结果，也不知道其中的JSON结构。我只想把它还给客户。

我希望这样的事情能奏效：

@RequestMapping(value = "/search/{index:.*}", method = RequestMethod.GET)
public void search(@PathVariable String index, @RequestParam Map allRequestParams, HttpServletResponse response)
    throws IOException
{
    BoolQueryBuilder query = QueryBuilders.boolQuery();
    for (Map.Entry entry : allRequestParams.entrySet()) {
        query.should(QueryBuilders.fuzzyQuery(entry.getKey(), entry.getValue()));
    }

    SearchResponse results = esClient.prepareSearch("nyc_visionzero")
        .setTypes("logs")
        .setQuery(query)
        .execute()
        .actionGet();

    SearchHits hits = results.getHits();
    hits.writeTo(response.getOutputStream());
}

但最后一行有一个编译错误,因为两个OutputStreams不兼容。所以我的问题是，将Elasticsearch的结果与Spring的响应连接起来的最简单的方法是什么？

Answer 1

您可以不尝试写入响应outputstream，而是更改搜索方法的签名以返回一个字符串，然后直接将结果作为有效的JSON返回。类似于：

@RequestMapping(value = "/search/{index:.*}", method = RequestMethod.GET)
public String search(@PathVariable String index, @RequestParam Map allRequestParams, HttpServletResponse response)
    throws IOException
{
    BoolQueryBuilder query = QueryBuilders.boolQuery();
    for (Map.Entry entry : allRequestParams.entrySet()) {
        query.should(QueryBuilders.fuzzyQuery(entry.getKey(), entry.getValue()));
    }

    SearchResponse results = esClient.prepareSearch("nyc_visionzero")
        .setTypes("logs")
        .setQuery(query)
        .execute()
        .actionGet();

    SearchHits hits = results.getHits();

    // Replacing hits.writeTo(response.getOutputStream()); below
    StringBuilder builder = new StringBuilder();
    SearchHit[] hitsDatas = hits.hits();
    int length = hitsDatas.length;
    builder.append("[");
    for (int i = 0; i < length; i++) {
       if (i == length - 1) {
          builder.append(hitsDatas[i].getSourceAsString());
       } else {
          builder.append(hitsDatas[i].getSourceAsString());
          builder.append(",");
       }
    }
    builder.append("]");
    return builder.toString();
}