在Apache Flink中注册java.util.List类型,可以通过以下步骤完成:
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-java</artifactId>
<version>1.13.2</version>
</dependency>
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.typeutils.TypeExtractor;
import org.apache.flink.api.java.typeutils.TypeInformationFactory;
import org.apache.flink.api.java.typeutils.TypeInformationResult;
import java.util.List;
public class ListTypeInfo<T> extends TypeInformation<List<T>> {
private final TypeInformation<T> elementType;
public ListTypeInfo(TypeInformation<T> elementType) {
this.elementType = elementType;
}
@Override
public boolean isBasicType() {
return false;
}
@Override
public boolean isTupleType() {
return false;
}
@Override
public int getArity() {
return 1;
}
@Override
public int getTotalFields() {
return 1;
}
@Override
public Class<List<T>> getTypeClass() {
return (Class<List<T>>) (Class<?>) List.class;
}
@Override
public boolean isKeyType() {
return false;
}
@Override
public TypeSerializer<List<T>> createSerializer(ExecutionConfig config) {
return new ListSerializer<>(elementType.createSerializer(config));
}
@Override
public String toString() {
return "List<" + elementType + ">";
}
public static <T> TypeInformation<List<T>> of(TypeInformation<T> elementType) {
return new ListTypeInfo<>(elementType);
}
public static <T> TypeInformation<List<T>> of(Class<T> elementType) {
return new ListTypeInfo<>(TypeExtractor.getForClass(elementType));
}
public static <T> TypeInformationResult<List<T>> createTypeInfo(TypeInformationFactory<List<T>> factory, TypeInformation<?>[] parameters, Annotation[] annotations) {
return TypeInformationResult.newBuilder(factory.createTypeInfo(parameters[0], annotations)).build();
}
}
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.typeutils.TypeExtractor;
public class FlinkListRegistrationExample {
public static void main(String[] args) throws Exception {
ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
env.getConfig().registerTypeWithKryoSerializer(List.class, new ListTypeInfo<>(TypeExtractor.getForClass(Object.class)));
// 其他Flink程序逻辑
}
}
通过以上步骤,就可以在Apache Flink中成功注册java.util.List类型,并在Flink程序中使用List类型进行数据处理。
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