Avro「建议收藏」

{ 
"namespace": "avro.domain", 
"type": "record", 
"name": "Test", 
"fields": [   
{ 
"name": "stringVar", "type": "string"},   
{ 
"name": "bytesVar", "type": ["bytes", "null"]},  
{ 
"name": "booleanVar",  "type": "boolean"},   
{ 
"name": "intVar",  "type": "int", "order":"descending"},   	
{ 
"name": "longVar",  "type": ["long", "null"], "order":"ascending"},   
{ 
"name": "floatVar",  "type": "float"},   
{ 
"name": "doubleVar",  "type": "double"},   
{ 
"name": "enumVar",  "type": { 
"type": "enum", "name": "Suit", "symbols" : ["SPADES ", "HEARTS", "DIAMONDS", "CLUBS"]}},   
{ 
"name": "strArrayVar", "type": { 
"type": "array", "items": "string"}},   
{ 
"name": "intArrayVar", "type": { 
"type": "array", "items": "int"}},     
{ 
"name": "mapVar", "type": { 
"type": "map", "values": "long"}},   
{ 
"name": "fixedVar", "type": { 
"type": "fixed", "size": 16, "name": "md5"}} 
] 

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!--日志依赖-->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.6.4</version>
<scope>compile</scope>
</dependency>
<dependency>
<!-- avro的依赖 -->
<groupId>org.apache.avro</groupId>
<artifactId>avro</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.apache.avro</groupId>
<artifactId>avro-ipc</artifactId>
<version>1.7.5</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
</plugin>
<plugin>
<groupId>org.apache.avro</groupId>
<artifactId>avro-maven-plugin</artifactId>
<version>1.7.5</version>
<executions>
<execution>
<id>schemas</id>
<phase>generate-sources</phase>
<goals>
<goal>schema</goal>
<goal>protocol</goal>
<goal>idl-protocol</goal>
</goals>
<configuration>
<!--存放avsc文件的地址-->
<sourceDirectory>${ 
project.basedir}/src/main/avro/</sourceDirectory>
<!--生成源码的地址-->
<outputDirectory>${ 
project.basedir}/src/main/java/</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>

{
"namespace":"avro.pojo",
"type":"record",
"name":"User",
"fields":
[
{"name":"name","type":"string"},
{"name":"age","type":"int"}
]
}

// User user = new User();
// user.setName("鲁智深");
// user.setAge(18);
// User user = new User("史进", 80);
// User user = User.newBuilder().setName("公孙胜").setAge(150).build();
// 利用原对象构建新对象
// 实际上底层是调用的clone方法来进行克隆
User user = User.newBuilder(new User("李逵", 80)).setAge(70).build();
System.out.println(user);

public void write() throws IOException { 

User user = new User("Amy", 40);
DatumWriter<User> dw = new SpecificDatumWriter<>(User.class);
DataFileWriter<User> dfw = new DataFileWriter<>(dw);
// 指定写出文件
dfw.create(user.getSchema(), new File("1.txt"));
dfw.append(user);
dfw.append(new User("Sam", 70));
dfw.append(new User("Bob", 70));
dfw.close();
}

public void read() throws IOException { 

DatumReader<User> dr = new SpecificDatumReader<>(User.class);
DataFileReader<User> dfr = new DataFileReader<>(new File("1.txt"), dr);
// 提供了迭代机制来迭代读取数据
// while(dfr.hasNext()){ 

//
// User user = dfr.next();
// System.out.println(user);
// }
// Lambda表达式
// dfr.forEach(u -> System.out.println(u));
// 对象方法的传递
dfr.forEach(System.out::println);
dfr.close();
}