Exits API 如果文档存在则返回true、如果不存在则返回false ``` GetRequest getRequest = new GetRequest( "posts", "1"); getRequest.fetchSourceContext(new FetchSourceContext(false)); //Disable fetching_source getRequest.storedFields("_none_");//禁用获取存储的字段 ``` 同步执行 ``` boolean exists = client.exists(getRequest, RequestOptions.DEFAULT); ``` 异步执行 ~~~ client.existsAsync(getRequest, RequestOptions.DEFAULT, listener); ~~~ ``` ActionListener<Boolean> listener = new ActionListener<Boolean>() { @Override public void onResponse(Boolean exists) { } @Override public void onFailure(Exception e) { } }; ```