142 lines
4.7 KiB
Java
142 lines
4.7 KiB
Java
package com.bizo.hive.serde.csv;
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import java.io.CharArrayReader;
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import java.io.IOException;
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import java.io.StringWriter;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.Properties;
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import org.apache.hadoop.conf.Configuration;
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import org.apache.hadoop.hive.serde.Constants;
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import org.apache.hadoop.hive.serde2.SerDe;
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import org.apache.hadoop.hive.serde2.SerDeException;
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import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
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import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
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import org.apache.hadoop.hive.serde2.objectinspector.StructField;
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import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
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import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
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import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
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import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
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import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
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import org.apache.hadoop.io.Text;
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import org.apache.hadoop.io.Writable;
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import au.com.bytecode.opencsv.CSVReader;
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import au.com.bytecode.opencsv.CSVWriter;
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/**
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* CSVSerde uses opencsv (http://opencsv.sourceforge.net/) to serialize/deserialize columns as CSV.
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*
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* @author Larry Ogrodnek <ogrodnek@gmail.com>
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*/
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public final class CSVSerde implements SerDe {
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private ObjectInspector inspector;
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private String[] outputFields;
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private int numCols;
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private List<String> row;
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@Override
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public void initialize(final Configuration conf, final Properties tbl) throws SerDeException {
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final List<String> columnNames = Arrays.asList(tbl.getProperty(Constants.LIST_COLUMNS).split(","));
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final List<TypeInfo> columnTypes = TypeInfoUtils.getTypeInfosFromTypeString(tbl.getProperty(Constants.LIST_COLUMN_TYPES));
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numCols = columnNames.size();
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final List<ObjectInspector> columnOIs = new ArrayList<ObjectInspector>(numCols);
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for (int i=0; i< numCols; i++) {
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columnOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
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}
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this.inspector = ObjectInspectorFactory.getStandardStructObjectInspector(columnNames, columnOIs);
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this.outputFields = new String[numCols];
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row = new ArrayList<String>(numCols);
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for (int i=0; i< numCols; i++) {
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row.add(null);
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}
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}
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@Override
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public Writable serialize(Object obj, ObjectInspector objInspector) throws SerDeException {
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final StructObjectInspector outputRowOI = (StructObjectInspector) objInspector;
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final List<? extends StructField> outputFieldRefs = outputRowOI.getAllStructFieldRefs();
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if (outputFieldRefs.size() != numCols) {
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throw new SerDeException("Cannot serialize the object because there are "
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+ outputFieldRefs.size() + " fields but the table has " + numCols + " columns.");
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}
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// Get all data out.
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for (int c = 0; c < numCols; c++) {
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final Object field = outputRowOI.getStructFieldData(obj, outputFieldRefs.get(c));
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final ObjectInspector fieldOI = outputFieldRefs.get(c).getFieldObjectInspector();
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// The data must be of type String
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final StringObjectInspector fieldStringOI = (StringObjectInspector) fieldOI;
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// Convert the field to Java class String, because objects of String type
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// can be stored in String, Text, or some other classes.
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outputFields[c] = fieldStringOI.getPrimitiveJavaObject(field);
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}
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final StringWriter writer = new StringWriter();
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final CSVWriter csv = new CSVWriter(writer, CSVWriter.DEFAULT_SEPARATOR, CSVWriter.DEFAULT_QUOTE_CHARACTER, "");
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try {
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csv.writeNext(outputFields);
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csv.close();
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return new Text(writer.toString());
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} catch (final IOException ioe) {
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throw new SerDeException(ioe);
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}
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}
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@Override
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public Object deserialize(final Writable blob) throws SerDeException {
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Text rowText = (Text) blob;
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CSVReader csv = null;
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try {
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csv = new CSVReader(new CharArrayReader(rowText.toString().toCharArray()));
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final String[] read = csv.readNext();
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for (int i=0; i< numCols; i++) {
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if (read != null && i < read.length) {
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row.set(i, read[i]);
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} else {
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row.set(i, null);
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}
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}
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return row;
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} catch (final Exception e) {
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throw new SerDeException(e);
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} finally {
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if (csv != null) {
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try {
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csv.close();
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} catch (final Exception e) {
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// ignore
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}
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}
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}
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}
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@Override
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public ObjectInspector getObjectInspector() throws SerDeException {
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return inspector;
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}
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@Override
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public Class<? extends Writable> getSerializedClass() {
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return Text.class;
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}
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}
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