使用 Java 转换 Apache Avro 为 Parquet 数据格式(依赖更新) | 隔叶黄莺 Yanbin Blog

2021-02-25 | 阅读(769)

在上篇使用 Java 转换 Apache Avro 为 Parquet 数据格式实现把 Avro 数据转换为 Parquet 文件或内存字节数组，并支持 LogicalType。其中使用到了 hadoop-core 依赖，注意到它传递的依赖都非常老旧，到官方 Maven 仓库一看才发现还不是一般的老

长时间无人问津的项目，那一定有它的替代品。对啦，据说 hadoop-core 在 2009 年 7 月份更名为 hadoop-common 了，没找到官方说明，只看到 StackOverflow 的 Differences between Hadoop-coomon, Hadoop-core and Hadoop-client? 是这么说的。应该是这么个说法，不然为何 hadoop-core 一直停留在 1.2.1 的版本，而且原来 hadoop-core 中的类在 hadoop-common 中可以找到，如类 org.apache.hadoop.fs.Path。不过在 hadoop-core-1.2.1 中的 fs/s3 包不见，这么重要的 s3 文件系统没了。

好了，针对上一篇，我们用活着的 hadoop-coomon 包来实现把 Avro 文件转换为 Parquet 文件或内存字节数组分别不同的 pom.xml 依赖配置，代码实现与前一篇使用 Java 转换 Apache Avro 为 Parquet 数据格式相同。

把 Avro 转换为 Parquet 文件的依赖

pom.xml 中依赖配置

<dependencies>
    <dependency>
        <groupId>org.apache.avro</groupId>
        <artifactId>avro</artifactId>
        <version>1.10.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.parquet</groupId>
        <artifactId>parquet-avro</artifactId>
        <version>1.11.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-common</artifactId>
        <version>3.3.0</version>
        <exclusions>
            <exclusion>
                <groupId>*</groupId>
                <artifactId>*</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-auth</artifactId>
        <version>3.3.0</version>
    </dependency>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.htrace</groupId>
        <artifactId>htrace-core4</artifactId>
        <version>4.1.0-incubating</version>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-configuration2</artifactId>
        <version>2.1.1</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.woodstox</groupId>
        <artifactId>woodstox-core</artifactId>
        <version>5.0.3</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>30.1-jre</version>
    </dependency>
    <dependency>
        <groupId>commons-collections</groupId>
        <artifactId>commons-collections</artifactId>
        <version>3.2.2</version>
    </dependency>
</dependencies>

<groupId>org.apache.avro</groupId>

</dependency>

<groupId>org.apache.parquet</groupId>

<artifactId>parquet-avro</artifactId>

</dependency>

<groupId>org.apache.hadoop</groupId>

<artifactId>hadoop-common</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.apache.hadoop</groupId>

<artifactId>hadoop-auth</artifactId>

</dependency>

<groupId>commons-logging</groupId>

<artifactId>commons-logging</artifactId>

</dependency>

<groupId>org.apache.htrace</groupId>

<artifactId>htrace-core4</artifactId>

<version>4.1.0-incubating</version>

</dependency>

<groupId>org.apache.commons</groupId>

<artifactId>commons-configuration2</artifactId>

</dependency>

<groupId>com.fasterxml.woodstox</groupId>

<artifactId>woodstox-core</artifactId>

</dependency>

<groupId>com.google.guava</groupId>

<artifactId>guava</artifactId>

</dependency>

<groupId>commons-collections</groupId>

<artifactId>commons-collections</artifactId>

</dependency>

</dependencies>

还是重复一下转换 Avro 为 Parquet 文件的代码

public static <T extends SpecificRecordBase> void writeToParquetFile(List<T> avroObjects) {
    Schema avroSchema = avroObjects.get(0).getSchema();
    GenericData genericData = GenericData.get();
    genericData.addLogicalTypeConversion(new TimeConversions.DateConversion());
    Path path = new Path("users.parquet");
    try (ParquetWriter<Object> writer = AvroParquetWriter.builder(path)
            .withDataModel(genericData)
            .withSchema(avroSchema)
            .withCompressionCodec(CompressionCodecName.SNAPPY)
            .withWriteMode(ParquetFileWriter.Mode.OVERWRITE)
            .build()) {
        avroObjects.forEach(r -> {
            try {
                writer.write(r);
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
        });
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static <T extends SpecificRecordBase> void writeToParquetFile(List<T> avroObjects) {

Schema avroSchema = avroObjects.get(0).getSchema();

GenericData genericData = GenericData.get();

genericData.addLogicalTypeConversion(new TimeConversions.DateConversion());

Path path = new Path("users.parquet");

try (ParquetWriter<Object> writer = AvroParquetWriter.builder(path)

.withDataModel(genericData)

.withSchema(avroSchema)

.withCompressionCodec(CompressionCodecName.SNAPPY)

.withWriteMode(ParquetFileWriter.Mode.OVERWRITE)

.build()) {

avroObjects.forEach(r -> {

try {

writer.write(r);

} catch (IOException ex) {

throw new UncheckedIOException(ex);

}

});

} catch (IOException e) {

e.printStackTrace();

}

AvroParquetWriter.builder() 这个方法中要用到 hadoop-common 的类 org.apache.hadoop.fs.Path。

转换 Avro 为内存字节数组的依赖

pom.xml

<dependencies>
    <dependency>
        <groupId>org.apache.avro</groupId>
        <artifactId>avro</artifactId>
        <version>1.10.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.parquet</groupId>
        <artifactId>parquet-avro</artifactId>
        <version>1.11.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-common</artifactId>
        <version>3.3.0</version>
        <exclusions>
            <exclusion>
                <groupId>*</groupId>
                <artifactId>*</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.woodstox</groupId>
        <artifactId>woodstox-core</artifactId>
        <version>5.0.3</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>30.1-jre</version>
    </dependency>
    <dependency>
        <groupId>commons-collections</groupId>
        <artifactId>commons-collections</artifactId>
        <version>3.2.2</version>
    </dependency>
</dependencies>

<groupId>org.apache.avro</groupId>

</dependency>

<groupId>org.apache.parquet</groupId>

<artifactId>parquet-avro</artifactId>

</dependency>

<groupId>org.apache.hadoop</groupId>

<artifactId>hadoop-common</artifactId>

</exclusion>

</exclusions>

</dependency>

<groupId>com.fasterxml.woodstox</groupId>

<artifactId>woodstox-core</artifactId>

</dependency>

<groupId>com.google.guava</groupId>

<artifactId>guava</artifactId>

</dependency>

<groupId>commons-collections</groupId>

<artifactId>commons-collections</artifactId>

</dependency>

</dependencies>

比前面生成 Parquet 文件要省几个依赖

再回顾一下内存中完成转换为 Parquet 字节数组的代码

public static <T extends SpecificRecordBase> byte[] writeToParquetByteArray(List<T> avroObjects) throws IOException {
    Schema avroSchema = avroObjects.get(0).getSchema();
    GenericData genericData = GenericData.get();
    genericData.addLogicalTypeConversion(new TimeConversions.DateConversion());
    InMemoryOutputFile outputFile = new InMemoryOutputFile();
    try (ParquetWriter<Object> writer = AvroParquetWriter.builder(outputFile)
            .withDataModel(genericData)
            .withSchema(avroSchema)
            .withCompressionCodec(CompressionCodecName.SNAPPY)
            .withWriteMode(ParquetFileWriter.Mode.CREATE)
            .build()) {
        avroObjects.forEach(r -> {
            try {
                writer.write(r);
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
        });
    } catch (IOException e) {
        e.printStackTrace();
    }

    return outputFile.toArray();
}

public static <T extends SpecificRecordBase> byte[] writeToParquetByteArray(List<T> avroObjects) throws IOException {

Schema avroSchema = avroObjects.get(0).getSchema();

GenericData genericData = GenericData.get();

genericData.addLogicalTypeConversion(new TimeConversions.DateConversion());

InMemoryOutputFile outputFile = new InMemoryOutputFile();

try (ParquetWriter<Object> writer = AvroParquetWriter.builder(outputFile)

.withDataModel(genericData)

.withSchema(avroSchema)

.withCompressionCodec(CompressionCodecName.SNAPPY)

.withWriteMode(ParquetFileWriter.Mode.CREATE)

.build()) {

avroObjects.forEach(r -> {

try {

writer.write(r);

} catch (IOException ex) {

throw new UncheckedIOException(ex);

}

});

} catch (IOException e) {

e.printStackTrace();

}

return outputFile.toArray();

}

InMemoryOutputFile 的内容再次重复如下

package yanbin.blog;

import org.apache.parquet.io.DelegatingPositionOutputStream;
import org.apache.parquet.io.OutputFile;
import org.apache.parquet.io.PositionOutputStream;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class InMemoryOutputFile implements OutputFile {
    private final ByteArrayOutputStream baos = new ByteArrayOutputStream();

    @Override
    public PositionOutputStream create(long blockSizeHint) throws IOException {
        return new InMemoryPositionOutputStream(baos);
    }

    @Override
    public PositionOutputStream createOrOverwrite(long blockSizeHint) throws IOException {
        return null;
    }

    @Override
    public boolean supportsBlockSize() {
        return false;
    }

    @Override
    public long defaultBlockSize() {
        return 0;
    }

    public byte[] toArray() {
        return baos.toByteArray();
    }

    private static class InMemoryPositionOutputStream extends DelegatingPositionOutputStream {

        public InMemoryPositionOutputStream(OutputStream outputStream) {
            super(outputStream);
        }

        @Override
        public long getPos() throws IOException {
            return ((ByteArrayOutputStream) this.getStream()).size();
        }
    }
}

package yanbin.blog;

import org.apache.parquet.io.DelegatingPositionOutputStream;

import org.apache.parquet.io.OutputFile;

import org.apache.parquet.io.PositionOutputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.OutputStream;

public class InMemoryOutputFile implements OutputFile {

private final ByteArrayOutputStream baos = new ByteArrayOutputStream();

@Override

public PositionOutputStream create(long blockSizeHint) throws IOException {

return new InMemoryPositionOutputStream(baos);

}

@Override

public PositionOutputStream createOrOverwrite(long blockSizeHint) throws IOException {

return null;

}

@Override

public boolean supportsBlockSize() {

return false;

}

@Override

public long defaultBlockSize() {

return 0;

}

public byte[] toArray() {

return baos.toByteArray();

}

private static class InMemoryPositionOutputStream extends DelegatingPositionOutputStream {

public InMemoryPositionOutputStream(OutputStream outputStream) {

super(outputStream);

}

@Override

public long getPos() throws IOException {

return ((ByteArrayOutputStream) this.getStream()).size();

}

以后还是尽量用 hadoop-common 库吧。

本文链接 https://yanbin.blog/convert-apache-avro-to-parquet-in-java-use-hadoop-common-instead-of-hadoop-core/, 来自隔叶黄莺 Yanbin Blog

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