Apache Avro:quick Start QuickStart and sample tutorials

This tutorial is written in reference to the quick start of the Apache Avro official website: http://avro.apache.org/docs/current/gettingstartedjava.html

1. Download Avro-tools-1.7.5.jar

http://mirrors.cnnic.cn/apache/avro/avro-1.7.5/java/

2. Generate Java code using Avro-tools

Write Avro Sample USER.AVRC

{' namespace ': ' Example.avro ', '  
 type ': ' Record ',  
 ' name ': ' User ',  
 ' Fields ': [  
     {' name ': ' Name ', ' type ': ' String '},  
     {' name ': ' Favorite_number ',  ' type ': [' int ', ' null ']},  
     {' name ': ' Favorite_Color ', ' type ': [' string "," null "]}  
 ]  
}

Execute in the directory where USER.AVRC is located:

Java-jar/path/to/avro-tools-1.7.5.jar Compile schema User.avsc.

Will be generated in this directory./example/avro/user.java program

3.maven build Eclipse Project write Java program serialization and deserialization of Avro files

The Pom.xml file for Maven is as follows:

<?xml version= "1.0" encoding= "UTF-8"?> <project xmlns= "http://maven.apache.org/POM/4.0.0" HT Tp://www.w3.org/2001/xmlschema-instance "xsi:schemalocation=" http://maven.apache.org/POM/4.0.0 http:// Maven.apache.org/xsd/maven-4.0.0.xsd "> <modelVersion>4.0.0</modelVersion> <groupid >com.iflytek.cpcloud</groupId> <artifactId>avro-test</artifactId> <version>0.1.0- snapshot</version> <dependencies> <dependency> <groupid>log4j</groupid > <artifactId>log4j</artifactId> <version>1.2.17</version> </dependenc y> <dependency> <groupId>commons-logging</groupId> <artifactid>commons-lo  
      gging</artifactid> <version>1.1.1</version> </dependency> <dependency> <groupId>commons-cli</groupId> 
      <artifactId>commons-cli</artifactId> <version>1.2</version> </dependency&  
    Gt  
      <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> </dependency> <dependency> <groupid>org.apache. avro</groupid> <artifactId>avro</artifactId> <version>1.7.5</version> </d ependency> </dependencies> <build> <plugins> <plugin> <ar Tifactid>maven-assembly-plugin</artifactid> <version>2.2-beta-5</version> <configurati On> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> & lt;/descriptorrefs> </configuration> </plugin> <plugin> <groupid>or G.apache.maven.plugins</groupid> <artifactId>maven-compiler-plugin</artifactId> <version>2.3.2</v  
      ersion> <configuration> <source>1.6</source> <target>1.6</target>  
  <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> </build> </project>

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MVN Build Eclipse Project

MVN Eclipse:eclipse

To import the generated User.java file above in the Example.avro package using Avro-tools

To import a generated project into eclipse

Write program serialization and reverse sequence Avro files Test.java

Package Example.avro;  
Import Java.io.File;  
      
Import java.io.IOException;  
Import Org.apache.avro.file.DataFileReader;  
Import Org.apache.avro.file.DataFileWriter;  
Import Org.apache.avro.io.DatumReader;  
Import Org.apache.avro.io.DatumWriter;  
Import Org.apache.avro.specific.SpecificDatumReader;  
      
Import Org.apache.avro.specific.SpecificDatumWriter;   
   public class Test {public static void main (string[] args) throws IOException {code ();  
  Decode ();  
    public static void code () throws ioexception{User User1 = new user ();  
    User1.setname ("Alyssa");  
    User1.setfavoritenumber (256);  
          
    Leave favorite Color Null//Alternate constructor User user2 = new User ("Ben", 7, "Red");  
        Construct via builder User User3 = User.newbuilder (). SetName ("Charlie"). Setfavoritecolor ("Blue")  
    . Setfavoritenumber (NULL). Build ();  User User4 = New User ("Jimmy", 7, "yellow");
    Serialize user1 and user2 to disk File = new file ("Users.avro");  
    datumwriter<user> userdatumwriter = new specificdatumwriter<user> (user.class);  
    datafilewriter<user> datafilewriter = new datafilewriter<user> (userdatumwriter);  
    Datafilewriter.create (User1.getschema (), New File ("Users.avro"));  
    Datafilewriter.append (user1);  
    Datafilewriter.append (User2);  
    Datafilewriter.append (USER3);  
    Datafilewriter.append (USER4);  
  Datafilewriter.close (); public static void Decode () throws ioexception{//deserialize Users from disk Datumreader<user  
    > userdatumreader = new specificdatumreader<user> (user.class);  
    File File = new file ("Users.avro");  
    datafilereader<user> Datafilereader = new datafilereader<user> (file, userdatumreader);  
    User user = null; while (Datafilereader.hasnext ()) {//Reuse user object by passing itTo next ().  
    This is saves us from//allocating and garbage collecting many to files with//objects items.  
    user = Datafilereader.next (user);  
    SYSTEM.OUT.PRINTLN (user); }  
  }  
}

The results of the operation are as follows:

{' name ': ' Alyssa ', ' favorite_number ': 256, ' Favorite_Color ': null}  
{"Name": "Ben", "Favorite_number": 7, "Favorite_Color": "Red"}  
{"Name": "Charlie", "Favorite_number": null, "Favorite_Color": "Blue"}  
{"Name": "Jimmy", "Favorite_number": 7, "Favorite_Color": "Yellow"}

Generates Users.avro files in the root directory of Eclipse engineering