I have 2 java functions:
listeFilesHdfs
return a list of files that stored in HDFS, for example:
If you remark, the files that stored in HDFS there content is a JSON format, for example:
{ "name":"Name", "type":"string" }, { "name":"Version", "type":"string" }, { "name":"r_service", "type":"string" }, { "name":"r_timestamp", "type":"long" },
I created the below function to call both function above (one return list of files and the second open a path):
How can I modify my function to read the files content and to add each file content to the JSON array and return an array of JSON ? Thanks
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Answer
As by your comment answer, you are looking for a way to parse the json content of the files into a javax.json-JsonArray
.
The answer is the class JsonReader
.
As per the documentation:
JsonReaderFactory factory = Json.createReaderFactory(...); JsonReader reader = factory.createReader(...); JsonStructure content = Jsonreader.read();
That JsonStructure could then be a JsonArray (and you may cast to it, after checking the class).
It might work like this (though I can’t test it):
public JSONArray getSchema() { String avroSchemaHDFSDir = "hdfs://hadoopcluster/schemas"; try(HdfsClient hdfsClient = new HdfsClient(nameNodeHosts, hadoopZks)) { for(int i = 0; i < hdfsClient.listeFilesHdfs(avroSchemaHDFSDir).size(); i++) { String fileContent = hdfsClient.listeFilesHdfs(avroSchemaHDFSDir).get(i).toString(); hdfsClient.openHdfsPath(file); JsonReaderFactory factory = Json.createReaderFactory(...); JsonReader reader = factory.createReader(...); JsonStructure content = Jsonreader.read(); if (content instanceof JsonArray) { return (JsonArray) content; } } } catch(Exception e) { logger.debug("get the specified schema ", e.getMessage()); } return null; }