parquet文件的一些操作

/**
 * 获取schema信息
 * @throws IOException
 */
@Test
public void testGetSchema() throws IOException {
    Configuration configuration = new Configuration(true);
    configuration.set("fs.defaultFS","hdfs://10.0.1.xx:9000");
    ParquetMetadata readFooter = null;
    Path parquetFilePath = new Path("/user/yanglei/parquet/douban.parquet");
    readFooter = ParquetFileReader.readFooter(configuration, parquetFilePath, ParquetMetadataConverter.NO_FILTER);
    MessageType schema =readFooter.getFileMetaData().getSchema();
    System.out.println(schema.toString());
}

public static final MessageType FILE_SCHEMA = Types.buildMessage()
        .required(PrimitiveType.PrimitiveTypeName.BINARY).named("user_name")
        .required(PrimitiveType.PrimitiveTypeName.INT64).named("bookid")
        .required(PrimitiveType.PrimitiveTypeName.INT32).named("bookscore")
        .named("douban");

/**
 * 写parquet文件
 * @throws Exception
 */
@Test
public void testWriteParquet() throws Exception {
    Configuration conf = new Configuration(true);
    conf.set("fs.defaultFS","hdfs://10.0.1.xx:9000");

    String file = "/user/yanglei/parquet/douban.parquet";
    Path path = new Path(file);
    FileSystem fs = path.getFileSystem(conf);
    if (fs.exists(path)) {
        fs.delete(path, true);
    }
    GroupWriteSupport.setSchema(FILE_SCHEMA, conf);
    SimpleGroupFactory f = new SimpleGroupFactory(FILE_SCHEMA);
    ParquetWriter<Group> writer = new ParquetWriter<>(path, new GroupWriteSupport(),
            CompressionCodecName.GZIP, 1024, 1024, 512, true, false, ParquetProperties.WriterVersion.PARQUET_2_0, conf);

    for (int i = 0; i < 1000; i++) {

        writer.write(
                f.newGroup()
                        .append("user_name", String.valueOf(i))
                        .append("bookid", 64l)
                        .append("bookscore",i));
    }
    writer.close();
}