java 写入parquet 代码
时间: 2023-07-03 20:27:42 浏览: 55
以下是Java写入Parquet文件的示例代码:
```java
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.parquet.hadoop.ParquetWriter;
import org.apache.parquet.hadoop.metadata.CompressionCodecName;
import org.apache.parquet.schema.MessageType;
import org.apache.parquet.schema.MessageTypeParser;
import org.apache.parquet.schema.Types;
import org.apache.parquet.example.data.Group;
import org.apache.parquet.example.data.simple.SimpleGroupFactory;
import org.apache.parquet.hadoop.example.GroupWriteSupport;
import java.io.IOException;
public class ParquetWriterExample {
public static void main(String[] args) throws IOException {
// 定义Parquet文件的schema
String schemaString = "message example {\n" +
"required int32 id;\n" +
"required binary name;\n" +
"optional int32 age;\n" +
"}";
MessageType schema = MessageTypeParser.parseMessageType(schemaString);
// 创建一个SimpleGroupFactory,用于创建Group对象
SimpleGroupFactory groupFactory = new SimpleGroupFactory(schema);
// 配置ParquetWriter
Configuration conf = new Configuration();
GroupWriteSupport writeSupport = new GroupWriteSupport();
GroupWriteSupport.setSchema(schema, conf);
ParquetWriter<Group> writer = new ParquetWriter<Group>(
new Path("example.parquet"),
writeSupport,
CompressionCodecName.SNAPPY,
1024,
1024,
512,
true,
false,
ParquetProperties.WriterVersion.PARQUET_2_0,
conf);
// 写入数据
Group group = groupFactory.newGroup()
.append("id", 1)
.append("name", "Alice")
.append("age", 20);
writer.write(group);
group = groupFactory.newGroup()
.append("id", 2)
.append("name", "Bob");
writer.write(group);
// 关闭writer
writer.close();
}
}
```
这个示例程序定义了一个Parquet文件的schema,创建了一个SimpleGroupFactory用于创建Group对象,然后使用ParquetWriter将数据写入Parquet文件。在写入数据之前,需要先配置ParquetWriter。最后,使用close()方法关闭writer。