我试过下面的avro schema:
{
"type": "record",
"name": "Tests",
"fields": [
{
"name": "name",
"alias": "first_name",
"type": "string",
"default": ""
}
]
}
编译schema"这使用avro工具，我得到相应的java文件。
/**
* Autogenerated by Avro
*
* DO NOT EDIT DIRECTLY
*/
import org.apache.avro.generic.GenericArray;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.util.Utf8;
import org.apache.avro.message.BinaryMessageEncoder;
import org.apache.avro.message.BinaryMessageDecoder;
import org.apache.avro.message.SchemaStore;
@org.apache.avro.specific.AvroGenerated
public class Tests extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
private static final long serialVersionUID = 8259235364501890516L;
public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{"type":"record","name":"Tests","fields":[{"name":"name","type":"string","default":"","alias":"first_name"}]}");
public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
private static SpecificData MODEL$ = new SpecificData();
private static final BinaryMessageEncoder<Tests> ENCODER =
new BinaryMessageEncoder<Tests>(MODEL$, SCHEMA$);
private static final BinaryMessageDecoder<Tests> DECODER =
new BinaryMessageDecoder<Tests>(MODEL$, SCHEMA$);
/**
* Return the BinaryMessageEncoder instance used by this class.
* @return the message encoder used by this class
*/
public static BinaryMessageEncoder<Tests> getEncoder() {
return ENCODER;
}
/**
* Return the BinaryMessageDecoder instance used by this class.
* @return the message decoder used by this class
*/
public static BinaryMessageDecoder<Tests> getDecoder() {
return DECODER;
}
/**
* Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
* @param resolver a {@link SchemaStore} used to find schemas by fingerprint
* @return a BinaryMessageDecoder instance for this class backed by the given SchemaStore
*/
public static BinaryMessageDecoder<Tests> createDecoder(SchemaStore resolver) {
return new BinaryMessageDecoder<Tests>(MODEL$, SCHEMA$, resolver);
}
/**
* Serializes this Tests to a ByteBuffer.
* @return a buffer holding the serialized data for this instance
* @throws java.io.IOException if this instance could not be serialized
*/
public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
return ENCODER.encode(this);
}
/**
* Deserializes a Tests from a ByteBuffer.
* @param b a byte buffer holding serialized data for an instance of this class
* @return a Tests instance decoded from the given buffer
* @throws java.io.IOException if the given bytes could not be deserialized into an instance of this class
*/
public static Tests fromByteBuffer(
java.nio.ByteBuffer b) throws java.io.IOException {
return DECODER.decode(b);
}
private java.lang.CharSequence name;
/**
* Default constructor. Note that this does not initialize fields
* to their default values from the schema. If that is desired then
* one should use <code>newBuilder()</code>.
*/
public Tests() {}
/**
* All-args constructor.
* @param name The new value for name
*/
public Tests(java.lang.CharSequence name) {
this.name = name;
}
public org.apache.avro.specific.SpecificData getSpecificData() { return MODEL$; }
public org.apache.avro.Schema getSchema() { return SCHEMA$; }
// Used by DatumWriter. Applications should not call.
public java.lang.Object get(int field$) {
switch (field$) {
case 0: return name;
default: throw new IndexOutOfBoundsException("Invalid index: " + field$);
}
}
// Used by DatumReader. Applications should not call.
@SuppressWarnings(value="unchecked")
public void put(int field$, java.lang.Object value$) {
switch (field$) {
case 0: name = (java.lang.CharSequence)value$; break;
default: throw new IndexOutOfBoundsException("Invalid index: " + field$);
}
}
/**
* Gets the value of the 'name' field.
* @return The value of the 'name' field.
*/
public java.lang.CharSequence getName() {
return name;
}
/**
* Sets the value of the 'name' field.
* @param value the value to set.
*/
public void setName(java.lang.CharSequence value) {
this.name = value;
}
/**
* Creates a new Tests RecordBuilder.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder() {
return new Tests.Builder();
}
/**
* Creates a new Tests RecordBuilder by copying an existing Builder.
* @param other The existing builder to copy.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder(Tests.Builder other) {
if (other == null) {
return new Tests.Builder();
} else {
return new Tests.Builder(other);
}
}
/**
* Creates a new Tests RecordBuilder by copying an existing Tests instance.
* @param other The existing instance to copy.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder(Tests other) {
if (other == null) {
return new Tests.Builder();
} else {
return new Tests.Builder(other);
}
}
/**
* RecordBuilder for Tests instances.
*/
@org.apache.avro.specific.AvroGenerated
public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<Tests>
implements org.apache.avro.data.RecordBuilder<Tests> {
private java.lang.CharSequence name;
/** Creates a new Builder */
private Builder() {
super(SCHEMA$);
}
/**
* Creates a Builder by copying an existing Builder.
* @param other The existing Builder to copy.
*/
private Builder(Tests.Builder other) {
super(other);
if (isValidValue(fields()[0], other.name)) {
this.name = data().deepCopy(fields()[0].schema(), other.name);
fieldSetFlags()[0] = other.fieldSetFlags()[0];
}
}
/**
* Creates a Builder by copying an existing Tests instance
* @param other The existing instance to copy.
*/
private Builder(Tests other) {
super(SCHEMA$);
if (isValidValue(fields()[0], other.name)) {
this.name = data().deepCopy(fields()[0].schema(), other.name);
fieldSetFlags()[0] = true;
}
}
/**
* Gets the value of the 'name' field.
* @return The value.
*/
public java.lang.CharSequence getName() {
return name;
}
/**
* Sets the value of the 'name' field.
* @param value The value of 'name'.
* @return This builder.
*/
public Tests.Builder setName(java.lang.CharSequence value) {
validate(fields()[0], value);
this.name = value;
fieldSetFlags()[0] = true;
return this;
}
/**
* Checks whether the 'name' field has been set.
* @return True if the 'name' field has been set, false otherwise.
*/
public boolean hasName() {
return fieldSetFlags()[0];
}
/**
* Clears the value of the 'name' field.
* @return This builder.
*/
public Tests.Builder clearName() {
name = null;
fieldSetFlags()[0] = false;
return this;
}
@Override
@SuppressWarnings("unchecked")
public Tests build() {
try {
Tests record = new Tests();
record.name = fieldSetFlags()[0] ? this.name : (java.lang.CharSequence) defaultValue(fields()[0]);
return record;
} catch (org.apache.avro.AvroMissingFieldException e) {
throw e;
} catch (java.lang.Exception e) {
throw new org.apache.avro.AvroRuntimeException(e);
}
}
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumWriter<Tests>
WRITER$ = (org.apache.avro.io.DatumWriter<Tests>)MODEL$.createDatumWriter(SCHEMA$);
@Override public void writeExternal(java.io.ObjectOutput out)
throws java.io.IOException {
WRITER$.write(this, SpecificData.getEncoder(out));
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumReader<Tests>
READER$ = (org.apache.avro.io.DatumReader<Tests>)MODEL$.createDatumReader(SCHEMA$);
@Override public void readExternal(java.io.ObjectInput in)
throws java.io.IOException {
READER$.read(this, SpecificData.getDecoder(in));
}
@Override protected boolean hasCustomCoders() { return true; }
@Override public void customEncode(org.apache.avro.io.Encoder out)
throws java.io.IOException
{
out.writeString(this.name);
}
@Override public void customDecode(org.apache.avro.io.ResolvingDecoder in)
throws java.io.IOException
{
org.apache.avro.Schema.Field[] fieldOrder = in.readFieldOrderIfDiff();
if (fieldOrder == null) {
this.name = in.readString(this.name instanceof Utf8 ? (Utf8)this.name : null);
} else {
for (int i = 0; i < 1; i++) {
switch (fieldOrder[i].pos()) {
case 0:
this.name = in.readString(this.name instanceof Utf8 ? (Utf8)this.name : null);
break;
default:
throw new java.io.IOException("Corrupt ResolvingDecoder.");
}
}
}
}
}
我想知道在哪里getter/setter别名?我怎么使用它?我明白，如果我有avro记录，那么我可以使用别名，但我如何生成avro记录使用Java文件使用该别名?
aliases负责为字段提供替代名称。Apache Avro.
如果您将alias更新为aliases，这将工作:
{
"type": "record",
"name": "Tests",
"fields": [
{
"name": "first_name",
"aliases": ["former_name_of_field"],
"type": "string",
"default": ""
}
]
}
可选字段支持模式演化。
/**
* Autogenerated by Avro
*
* DO NOT EDIT DIRECTLY
*/
import org.apache.avro.generic.GenericArray;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.util.Utf8;
import org.apache.avro.message.BinaryMessageEncoder;
import org.apache.avro.message.BinaryMessageDecoder;
import org.apache.avro.message.SchemaStore;
@org.apache.avro.specific.AvroGenerated
public class Tests extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
private static final long serialVersionUID = -2440753220882419647L;
public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{"type":"record","name":"Tests","fields":[{"name":"first_name","type":{"type":"string","avro.java.string":"String"},"default":"","aliases":["former_name_of_field"]}]}");
public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
private static SpecificData MODEL$ = new SpecificData();
private static final BinaryMessageEncoder<Tests> ENCODER =
new BinaryMessageEncoder<Tests>(MODEL$, SCHEMA$);
private static final BinaryMessageDecoder<Tests> DECODER =
new BinaryMessageDecoder<Tests>(MODEL$, SCHEMA$);
/**
* Return the BinaryMessageEncoder instance used by this class.
* @return the message encoder used by this class
*/
public static BinaryMessageEncoder<Tests> getEncoder() {
return ENCODER;
}
/**
* Return the BinaryMessageDecoder instance used by this class.
* @return the message decoder used by this class
*/
public static BinaryMessageDecoder<Tests> getDecoder() {
return DECODER;
}
/**
* Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
* @param resolver a {@link SchemaStore} used to find schemas by fingerprint
* @return a BinaryMessageDecoder instance for this class backed by the given SchemaStore
*/
public static BinaryMessageDecoder<Tests> createDecoder(SchemaStore resolver) {
return new BinaryMessageDecoder<Tests>(MODEL$, SCHEMA$, resolver);
}
/**
* Serializes this Tests to a ByteBuffer.
* @return a buffer holding the serialized data for this instance
* @throws java.io.IOException if this instance could not be serialized
*/
public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
return ENCODER.encode(this);
}
/**
* Deserializes a Tests from a ByteBuffer.
* @param b a byte buffer holding serialized data for an instance of this class
* @return a Tests instance decoded from the given buffer
* @throws java.io.IOException if the given bytes could not be deserialized into an instance of this class
*/
public static Tests fromByteBuffer(
java.nio.ByteBuffer b) throws java.io.IOException {
return DECODER.decode(b);
}
@Deprecated public java.lang.String first_name;
/**
* Default constructor. Note that this does not initialize fields
* to their default values from the schema. If that is desired then
* one should use <code>newBuilder()</code>.
*/
public Tests() {}
/**
* All-args constructor.
* @param first_name The new value for first_name
*/
public Tests(java.lang.String first_name) {
this.first_name = first_name;
}
public org.apache.avro.specific.SpecificData getSpecificData() { return MODEL$; }
public org.apache.avro.Schema getSchema() { return SCHEMA$; }
// Used by DatumWriter. Applications should not call.
public java.lang.Object get(int field$) {
switch (field$) {
case 0: return first_name;
default: throw new IndexOutOfBoundsException("Invalid index: " + field$);
}
}
// Used by DatumReader. Applications should not call.
@SuppressWarnings(value="unchecked")
public void put(int field$, java.lang.Object value$) {
switch (field$) {
case 0: first_name = value$ != null ? value$.toString() : null; break;
default: throw new IndexOutOfBoundsException("Invalid index: " + field$);
}
}
/**
* Gets the value of the 'first_name' field.
* @return The value of the 'first_name' field.
*/
public java.lang.String getFirstName() {
return first_name;
}
/**
* Sets the value of the 'first_name' field.
* @param value the value to set.
*/
public void setFirstName(java.lang.String value) {
this.first_name = value;
}
/**
* Creates a new Tests RecordBuilder.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder() {
return new Tests.Builder();
}
/**
* Creates a new Tests RecordBuilder by copying an existing Builder.
* @param other The existing builder to copy.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder(Tests.Builder other) {
if (other == null) {
return new Tests.Builder();
} else {
return new Tests.Builder(other);
}
}
/**
* Creates a new Tests RecordBuilder by copying an existing Tests instance.
* @param other The existing instance to copy.
* @return A new Tests RecordBuilder
*/
public static Tests.Builder newBuilder(Tests other) {
if (other == null) {
return new Tests.Builder();
} else {
return new Tests.Builder(other);
}
}
/**
* RecordBuilder for Tests instances.
*/
@org.apache.avro.specific.AvroGenerated
public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<Tests>
implements org.apache.avro.data.RecordBuilder<Tests> {
private java.lang.String first_name;
/** Creates a new Builder */
private Builder() {
super(SCHEMA$);
}
/**
* Creates a Builder by copying an existing Builder.
* @param other The existing Builder to copy.
*/
private Builder(Tests.Builder other) {
super(other);
if (isValidValue(fields()[0], other.first_name)) {
this.first_name = data().deepCopy(fields()[0].schema(), other.first_name);
fieldSetFlags()[0] = other.fieldSetFlags()[0];
}
}
/**
* Creates a Builder by copying an existing Tests instance
* @param other The existing instance to copy.
*/
private Builder(Tests other) {
super(SCHEMA$);
if (isValidValue(fields()[0], other.first_name)) {
this.first_name = data().deepCopy(fields()[0].schema(), other.first_name);
fieldSetFlags()[0] = true;
}
}
/**
* Gets the value of the 'first_name' field.
* @return The value.
*/
public java.lang.String getFirstName() {
return first_name;
}
/**
* Sets the value of the 'first_name' field.
* @param value The value of 'first_name'.
* @return This builder.
*/
public Tests.Builder setFirstName(java.lang.String value) {
validate(fields()[0], value);
this.first_name = value;
fieldSetFlags()[0] = true;
return this;
}
/**
* Checks whether the 'first_name' field has been set.
* @return True if the 'first_name' field has been set, false otherwise.
*/
public boolean hasFirstName() {
return fieldSetFlags()[0];
}
/**
* Clears the value of the 'first_name' field.
* @return This builder.
*/
public Tests.Builder clearFirstName() {
first_name = null;
fieldSetFlags()[0] = false;
return this;
}
@Override
@SuppressWarnings("unchecked")
public Tests build() {
try {
Tests record = new Tests();
record.first_name = fieldSetFlags()[0] ? this.first_name : (java.lang.String) defaultValue(fields()[0]);
return record;
} catch (org.apache.avro.AvroMissingFieldException e) {
throw e;
} catch (java.lang.Exception e) {
throw new org.apache.avro.AvroRuntimeException(e);
}
}
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumWriter<Tests>
WRITER$ = (org.apache.avro.io.DatumWriter<Tests>)MODEL$.createDatumWriter(SCHEMA$);
@Override public void writeExternal(java.io.ObjectOutput out)
throws java.io.IOException {
WRITER$.write(this, SpecificData.getEncoder(out));
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumReader<Tests>
READER$ = (org.apache.avro.io.DatumReader<Tests>)MODEL$.createDatumReader(SCHEMA$);
@Override public void readExternal(java.io.ObjectInput in)
throws java.io.IOException {
READER$.read(this, SpecificData.getDecoder(in));
}
@Override protected boolean hasCustomCoders() { return true; }
@Override public void customEncode(org.apache.avro.io.Encoder out)
throws java.io.IOException
{
out.writeString(this.first_name);
}
@Override public void customDecode(org.apache.avro.io.ResolvingDecoder in)
throws java.io.IOException
{
org.apache.avro.Schema.Field[] fieldOrder = in.readFieldOrderIfDiff();
if (fieldOrder == null) {
this.first_name = in.readString();
} else {
for (int i = 0; i < 1; i++) {
switch (fieldOrder[i].pos()) {
case 0:
this.first_name = in.readString();
break;
default:
throw new java.io.IOException("Corrupt ResolvingDecoder.");
}
}
}
}
}
我不相信可以通过Java代码来设置别名。