Avro的java实现

基于Apache Avro™ 1.10.2 版本的Java实现 环境准备

• IDEA 2020.1
• JDK1.8
• Maven 3.3.9

工程目录

• src/main/avro文件夹是用来存放schema定义.avsc文件和序列化结果文件.avro
• com.donny.avro目录下是采用为.avsc生成Java类的方式实现的代码
• com.donny.schema目录中是采用schema的方式，不需要为.avsc生成Java类的方式实现的代码

pom.xml配置

    4.0.0

    org.example
    avrodemo
    1.0-SNAPSHOT

    
        
            org.apache.avro
            avro
            1.10.2
        
    

    
        
            
                org.apache.avro
                avro-maven-plugin
                1.10.2
                
                    
                        generate-sources
                        
                            schema
                        
                        
                            ${project.basedir}/src/main/avro/
                            ${project.basedir}/src/main/java/
                        
                    
                
            
            
                org.apache.maven.plugins
                maven-compiler-plugin
                
                    1.8
                    1.8
                
            
        
    

avro-maven-plugin插件可以帮助将user.avsc转换出UserJava类文件

com.donny.avro目录下之中的文件 User.java文件

建议不拷贝，直接通过插件生成。

/**
 * Autogenerated by Avro
 *
 * DO NOT EDIT DIRECTLY
 */
package com.donny.avro;

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 User extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
  private static final long serialVersionUID = 820790187725012134L;
  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"User\",\"namespace\":\"com.donny.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 BinaryMessageEncoder instance used by this class.
   * @return the message encoder used by this class
   */
  public static BinaryMessageEncoder getEncoder() {
    return ENCODER;
  }

  /**
   * Return the BinaryMessageDecoder instance used by this class.
   * @return the message decoder 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
   * @return a BinaryMessageDecoder instance for this class backed by the given SchemaStore
   */
  public static BinaryMessageDecoder createDecoder(SchemaStore resolver) {
    return new BinaryMessageDecoder(MODEL$, SCHEMA$, resolver);
  }

  /**
   * Serializes this User 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 User from a ByteBuffer.
   * @param b a byte buffer holding serialized data for an instance of this class
   * @return a User 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 User fromByteBuffer(
      java.nio.ByteBuffer b) throws java.io.IOException {
    return DECODER.decode(b);
  }

   private java.lang.CharSequence name;
   private java.lang.Integer favorite_number;
   private 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.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;
    case 1: return favorite_number;
    case 2: return favorite_color;
    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;
    case 1: favorite_number = (java.lang.Integer)value$; break;
    case 2: favorite_color = (java.lang.CharSequence)value$; 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;
  }

  /**
   * 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 com.donny.avro.User.Builder newBuilder() {
    return new com.donny.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 com.donny.avro.User.Builder newBuilder(com.donny.avro.User.Builder other) {
    if (other == null) {
      return new com.donny.avro.User.Builder();
    } else {
      return new com.donny.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 com.donny.avro.User.Builder newBuilder(com.donny.avro.User other) {
    if (other == null) {
      return new com.donny.avro.User.Builder();
    } else {
      return new com.donny.avro.User.Builder(other);
    }
  }

  /**
   * RecordBuilder for User instances.
   */
  @org.apache.avro.specific.AvroGenerated
  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(com.donny.avro.User.Builder other) {
      super(other);
      if (isValidValue(fields()[0], other.name)) {
        this.name = data().deepCopy(fields()[0].schema(), other.name);
        fieldSetFlags()[0] = other.fieldSetFlags()[0];
      }
      if (isValidValue(fields()[1], other.favorite_number)) {
        this.favorite_number = data().deepCopy(fields()[1].schema(), other.favorite_number);
        fieldSetFlags()[1] = other.fieldSetFlags()[1];
      }
      if (isValidValue(fields()[2], other.favorite_color)) {
        this.favorite_color = data().deepCopy(fields()[2].schema(), other.favorite_color);
        fieldSetFlags()[2] = other.fieldSetFlags()[2];
      }
    }

    /**
     * Creates a Builder by copying an existing User instance
     * @param other The existing instance to copy.
     */
    private Builder(com.donny.avro.User other) {
      super(SCHEMA$);
      if (isValidValue(fields()[0], other.name)) {
        this.name = data().deepCopy(fields()[0].schema(), other.name);
        fieldSetFlags()[0] = true;
      }
      if (isValidValue(fields()[1], other.favorite_number)) {
        this.favorite_number = data().deepCopy(fields()[1].schema(), other.favorite_number);
        fieldSetFlags()[1] = true;
      }
      if (isValidValue(fields()[2], other.favorite_color)) {
        this.favorite_color = data().deepCopy(fields()[2].schema(), other.favorite_color);
        fieldSetFlags()[2] = 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 com.donny.avro.User.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 com.donny.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 com.donny.avro.User.Builder setFavoriteNumber(java.lang.Integer value) {
      validate(fields()[1], value);
      this.favorite_number = value;
      fieldSetFlags()[1] = true;
      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 com.donny.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 com.donny.avro.User.Builder setFavoriteColor(java.lang.CharSequence value) {
      validate(fields()[2], value);
      this.favorite_color = value;
      fieldSetFlags()[2] = true;
      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 com.donny.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 (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
    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));
  }

  @Override protected boolean hasCustomCoders() { return true; }

  @Override public void customEncode(org.apache.avro.io.Encoder out)
    throws java.io.IOException
  {
    out.writeString(this.name);

    if (this.favorite_number == null) {
      out.writeIndex(1);
      out.writeNull();
    } else {
      out.writeIndex(0);
      out.writeInt(this.favorite_number);
    }

    if (this.favorite_color == null) {
      out.writeIndex(1);
      out.writeNull();
    } else {
      out.writeIndex(0);
      out.writeString(this.favorite_color);
    }

  }

  @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);

      if (in.readIndex() != 0) {
        in.readNull();
        this.favorite_number = null;
      } else {
        this.favorite_number = in.readInt();
      }

      if (in.readIndex() != 0) {
        in.readNull();
        this.favorite_color = null;
      } else {
        this.favorite_color = in.readString(this.favorite_color instanceof Utf8 ? (Utf8)this.favorite_color : null);
      }

    } else {
      for (int i = 0; i