avro java_avro序列化框架实践(一)根据schema文件反向生成java类
原標題：avro序列化框架實踐(一)根據schema文件反向生成java類
avro是一款序列化框架，定義schema文件,可以生成java類，然后配合就可以序列化、反序列化對象。
定義user.avsc
{"namespace": "example.avro",
"type": "record",
"name": "User",
"fields": [
{"name": "name", "type": "string"},
{"name": "favorite_number", "type": ["int", "null"]},
{"name": "favorite_color", "type": ["string", "null"]}
]
}
執行命令
java -jar avro-tools-1.8.2.jar compile schema user.avsc .
產生的User類
exampleavroUser.java
/**
* Autogenerated by Avro
*
* DO NOT EDIT DIRECTLY
*/
package example.avro;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.message.BinaryMessageEncoder;
import org.apache.avro.message.BinaryMessageDecoder;
import org.apache.avro.message.SchemaStore;
@SuppressWarnings("all")
@org.apache.avro.specific.AvroGenerated
public class User extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
private static final long serialVersionUID = -3588479540582100558L;
public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{"type":"record","name":"User","namespace":"example.avro","fields":[{"name":"name","type":"string"},{"name":"favorite_number","type":["int","null"]},{"name":"favorite_color","type":["string","null"]}]}");
public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
private static SpecificData MODEL$ = new SpecificData();
private static final BinaryMessageEncoder ENCODER =
new BinaryMessageEncoder(MODEL$, SCHEMA$);
private static final BinaryMessageDecoder DECODER =
new BinaryMessageDecoder(MODEL$, SCHEMA$);
/**
* Return the BinaryMessageDecoder instance used by this class.
*/
public static BinaryMessageDecoder 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
*/
public static BinaryMessageDecoder createDecoder(SchemaStore resolver) {
return new BinaryMessageDecoder(MODEL$, SCHEMA$, resolver);
}
/** Serializes this User to a ByteBuffer. */
public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
return ENCODER.encode(this);
}
/** Deserializes a User from a ByteBuffer. */
public static User fromByteBuffer(
java.nio.ByteBuffer b) throws java.io.IOException {
return DECODER.decode(b);
}
@Deprecated public java.lang.CharSequence name;
@Deprecated public java.lang.Integer favorite_number;
@Deprecated public java.lang.CharSequence favorite_color;
/**
* Default constructor. Note that this does not initialize fields
* to their default values from the schema. If that is desired then
* one should use newBuilder().
*/
public User() {}
/**
* All-args constructor.
* @param name The new value for name
* @param favorite_number The new value for favorite_number
* @param favorite_color The new value for favorite_color
*/
public User(java.lang.CharSequence name, java.lang.Integer favorite_number, java.lang.CharSequence favorite_color) {
this.name = name;
this.favorite_number = favorite_number;
this.favorite_color = favorite_color;
}
public org.apache.avro.Schema getSchema() { return SCHEMA$; }
// Used by DatumWriter. Applications should not call.
public java.lang.Object get(int field$) {
switch (field$) {
case 0: return name;
case 1: return favorite_number;
case 2: return favorite_color;
default: throw new org.apache.avro.AvroRuntimeException("Bad index");
}
}
// Used by DatumReader. Applications should not call.
@SuppressWarnings(value="unchecked")
public void put(int field$, java.lang.Object value$) {
switch (field$) {
case 0: name = (java.lang.CharSequence)value$; break;
case 1: favorite_number = (java.lang.Integer)value$; break;
case 2: favorite_color = (java.lang.CharSequence)value$; break;
default: throw new org.apache.avro.AvroRuntimeException("Bad index");
}
}
/**
* 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;
}
/**
* Gets the value of the 'favorite_number' field.
* @return The value of the 'favorite_number' field.
*/
public java.lang.Integer getFavoriteNumber() {
return favorite_number;
}
/**
* Sets the value of the 'favorite_number' field.
* @param value the value to set.
*/
public void setFavoriteNumber(java.lang.Integer value) {
this.favorite_number = value;
}
/**
* Gets the value of the 'favorite_color' field.
* @return The value of the 'favorite_color' field.
*/
public java.lang.CharSequence getFavoriteColor() {
return favorite_color;
}
/**
* Sets the value of the 'favorite_color' field.
* @param value the value to set.
*/
public void setFavoriteColor(java.lang.CharSequence value) {
this.favorite_color = value;
}
/**
* Creates a new User RecordBuilder.
* @return A new User RecordBuilder
*/
public static example.avro.User.Builder newBuilder() {
return new example.avro.User.Builder();
}
/**
* Creates a new User RecordBuilder by copying an existing Builder.
* @param other The existing builder to copy.
* @return A new User RecordBuilder
*/
public static example.avro.User.Builder newBuilder(example.avro.User.Builder other) {
return new example.avro.User.Builder(other);
}
/**
* Creates a new User RecordBuilder by copying an existing User instance.
* @param other The existing instance to copy.
* @return A new User RecordBuilder
*/
public static example.avro.User.Builder newBuilder(example.avro.User other) {
return new example.avro.User.Builder(other);
}
/**
* RecordBuilder for User instances.
*/
public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase
implements org.apache.avro.data.RecordBuilder {
private java.lang.CharSequence name;
private java.lang.Integer favorite_number;
private java.lang.CharSequence favorite_color;
/** 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(example.avro.User.Builder other) {
super(other);
if (isValidValue(fields()[0], other.name)) {
this.name = data().deepCopy(fields()[0].schema(), other.name);
}
if (isValidValue(fields()[1], other.favorite_number)) {
this.favorite_number = data().deepCopy(fields()[1].schema(), other.favorite_number);
}
if (isValidValue(fields()[2], other.favorite_color)) {
this.favorite_color = data().deepCopy(fields()[2].schema(), other.favorite_color);
}
}
/**
* Creates a Builder by copying an existing User instance
* @param other The existing instance to copy.
*/
private Builder(example.avro.User other) {
super(SCHEMA$);
if (isValidValue(fields()[0], other.name)) {
this.name = data().deepCopy(fields()[0].schema(), other.name);
}
if (isValidValue(fields()[1], other.favorite_number)) {
this.favorite_number = data().deepCopy(fields()[1].schema(), other.favorite_number);
}
if (isValidValue(fields()[2], other.favorite_color)) {
this.favorite_color = data().deepCopy(fields()[2].schema(), other.favorite_color);
}
}
/**
* 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 example.avro.User.Builder setName(java.lang.CharSequence value) {
validate(fields()[0], value);
this.name = value;
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 example.avro.User.Builder clearName() {
name = null;
fieldSetFlags()[0] = false;
return this;
}
/**
* Gets the value of the 'favorite_number' field.
* @return The value.
*/
public java.lang.Integer getFavoriteNumber() {
return favorite_number;
}
/**
* Sets the value of the 'favorite_number' field.
* @param value The value of 'favorite_number'.
* @return This builder.
*/
public example.avro.User.Builder setFavoriteNumber(java.lang.Integer value) {
validate(fields()[1], value);
this.favorite_number = value;
return this;
}
/**
* Checks whether the 'favorite_number' field has been set.
* @return True if the 'favorite_number' field has been set, false otherwise.
*/
public boolean hasFavoriteNumber() {
return fieldSetFlags()[1];
}
/**
* Clears the value of the 'favorite_number' field.
* @return This builder.
*/
public example.avro.User.Builder clearFavoriteNumber() {
favorite_number = null;
fieldSetFlags()[1] = false;
return this;
}
/**
* Gets the value of the 'favorite_color' field.
* @return The value.
*/
public java.lang.CharSequence getFavoriteColor() {
return favorite_color;
}
/**
* Sets the value of the 'favorite_color' field.
* @param value The value of 'favorite_color'.
* @return This builder.
*/
public example.avro.User.Builder setFavoriteColor(java.lang.CharSequence value) {
validate(fields()[2], value);
this.favorite_color = value;
return this;
}
/**
* Checks whether the 'favorite_color' field has been set.
* @return True if the 'favorite_color' field has been set, false otherwise.
*/
public boolean hasFavoriteColor() {
return fieldSetFlags()[2];
}
/**
* Clears the value of the 'favorite_color' field.
* @return This builder.
*/
public example.avro.User.Builder clearFavoriteColor() {
favorite_color = null;
fieldSetFlags()[2] = false;
return this;
}
@Override
@SuppressWarnings("unchecked")
public User build() {
try {
User record = new User();
record.name = fieldSetFlags()[0] ? this.name : (java.lang.CharSequence) defaultValue(fields()[0]);
record.favorite_number = fieldSetFlags()[1] ? this.favorite_number : (java.lang.Integer) defaultValue(fields()[1]);
record.favorite_color = fieldSetFlags()[2] ? this.favorite_color : (java.lang.CharSequence) defaultValue(fields()[2]);
return record;
} catch (java.lang.Exception e) {
throw new org.apache.avro.AvroRuntimeException(e);
}
}
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumWriter
WRITER$ = (org.apache.avro.io.DatumWriter)MODEL$.createDatumWriter(SCHEMA$);
@Override public void writeExternal(java.io.ObjectOutput out)
throws java.io.IOException {
WRITER$.write(this, SpecificData.getEncoder(out));
}
@SuppressWarnings("unchecked")
private static final org.apache.avro.io.DatumReader
READER$ = (org.apache.avro.io.DatumReader)MODEL$.createDatumReader(SCHEMA$);
@Override public void readExternal(java.io.ObjectInput in)
throws java.io.IOException {
READER$.read(this, SpecificData.getDecoder(in));
}
}
---------------------
作者：pangPython
來源：CSDN
原文：https://blog.csdn.net/u012995856/article/details/84112338
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