获取 Parquet文件，解析为LIst<String>
package com.emcc.hiacloud.analytics.common.util;import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.apache.hadoop.fs.Path;
import org.apache.parquet.avro.AvroParquetReader;
import org.apache.parquet.hadoop.ParquetReader;import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;public class ParquetUtils {private static final String csvDelimiter = ",";public static Map<String,List<String[]>> viewParquet(String path,int maxLine) throws IOException {Map<String,List<String[]>> parquetInfo=new HashMap<>();List<String[]> dataList=new ArrayList<>();Schema.Field[] fields = null;String[] fieldNames = new String[0];try (ParquetReader<GenericData.Record> reader =AvroParquetReader.<GenericData.Record>builder(new Path(path)).build()){int x=0;GenericData.Record record;//解析Parquet数据逐行读取while ((record = reader.read()) != null && x<maxLine) {//读取第一行获取列头信息if (fields == null) {final List<Schema.Field> fieldsList = record.getSchema().getFields();fieldNames = getFieldNames(fields = fieldsList.toArray(new Schema.Field[0]));System.out.println("列头:"+String.join(csvDelimiter, fieldNames));dataList.add(fieldNames);parquetInfo.put("head",dataList);dataList=new ArrayList<>();}int i = 0;String[]dataString=new String[fieldNames.length];//读取数据获取列头信息for (final String fieldName : fieldNames) {String recordData=record.get(fieldName).toString();if(recordData.contains("type")){List<HashMap> dataFormValue=JSONArray.parseArray(JSONObject.parseObject(recordData).get("values").toString(),HashMap.class);StringBuilder datas = new StringBuilder();for(HashMap data:dataFormValue){datas.append(data.get("element").toString()).append(",");}datas.deleteCharAt(datas.length() - 1);recordData=datas.toString();}dataString[i++] =recordData;}dataList.add(dataString);++x;}}parquetInfo.put("data",dataList);return parquetInfo;}private static String[] getFieldNames(final Schema.Field[] fields) {final String[] fieldNames = new String[fields.length];int i = 0;for (final Schema.Field field : fields) {fieldNames[i++] = field.name();}return fieldNames;}
}