Question

我正在尝试从GenericRecord（Avro 1.8.2）检索字段的值

genericRecord.get(index) works but genericRecord.get(field_name) only gets me a null value.

        genericRecord =reader.read(null, decoder);
        ListIterator<Field> itr=  genericRecord.getSchema().getFields().listIterator(); 
        System.out.println("getting schema from generic record +" + genericRecord.getSchema());
        while(itr.hasNext())
        {   
            String nextField = itr.next().toString();
            System.out.println("field right now is :"+ nextField+" the value in the generic record is "+ genericRecord.get(nextField));
            binaryObjBuilder.setField(nextField, genericRecord.get(nextField));

        }
        for (int i=0;i<14;i++)
        {
            System.out.println("the values at index: "+i+" is "+ genericRecord.get(i));
        }

以上代码段的输出为

从通用记录+ {“ type”：“ record”，“ name”：“ customer_address”，“ namespace”：“ customer_address.avro”，“ fields”：[{“ name”：“ datetime”， “ type”：“ long”}，{“ name”：“ ca_address_sk”，“ tye”：[“ null”，“ long”]}，{“ name”：“ ca_address_id”，“ type”：[“ null” ，“ string”]}，{“ name”：“ ca_street_number”，“ type”：[“ null”，“ string”]}，{“ name”：“ ca_street_name”，“ type”：[“ null”，“ string“]}，{” name“：” ca_treet_type“，” type“：[” null“，” string“]}，{” name“：” ca_suite_number“，” type“：[” null“，” string“ ]}，{“ name”：“ ca_city”，“ type”：[“ null”，“ string”]}}，{“ name”：“ ca_county”，“ type”：[“ null”，“ string”]} ，{“ name：” ca_state“，” type“：[” null“，” string“]}，{” name“：” ca_zip“，” type“：[” null“，” string“]}，{” name“：” ca_country“，” type“：[” null“，” string“]}，{” name“：” ca_gmt_offset“，” type“：[” null“，” double“]}，{” name“ ：ca_location_type“，” type“：[” null“，” string“]}]}

field right now is :datetime type:LONG pos:0 the value in the generic record is null
field right now is :ca_address_sk type:UNION pos:1 the value in the generic record is null
field right now is :ca_address_id type:UNION pos:2 the value in the generic record is null
field right now is :ca_street_number type:UNION pos:3 the value in the generic record is null
field right now is :ca_street_name type:UNION pos:4 the value in the generic record is null
field right now is :ca_street_type type:UNION pos:5 the value in the generic record is null
field right now is :ca_suite_number type:UNION pos:6 the value in the generic record is null
field right now is :ca_city type:UNION pos:7 the value in the generic record is null
field right now is :ca_county type:UNION pos:8 the value in the generic record is null
field right now is :ca_state type:UNION pos:9 the value in the generic record is null
field right now is :ca_zip type:UNION pos:10 the value in the generic record is null
field right now is :ca_country type:UNION pos:11 the value in the generic record is null
field right now is :ca_gmt_offset type:UNION pos:12 the value in the generic record is null
field right now is :ca_location_type type:UNION pos:13 the value in the generic record is null

the values at index: 0 is `201812190510`
the values at index: 1 is `596508`
the values at index: 2 is `AAAAAAAAMBKBJAAA`
the values at index: 3 is 613
the values at index: 4 is 3rd
the values at index: 5 is Ln
the values at index: 6 is Suite 300
the values at index: 7 is Pleasant Hill
the values at index: 8 is Marion County
the values at index: 9 is OH
the values at index: 10 is 43604
the values at index: 11 is United States
the values at index: 12 is -5.0
the values at index: 13 is single family

Answer 1

如果您查看代码"field right now is :"+ nextField+"与输出field right now is :datetime type:LONG pos:0，那么您会看到它正在调用get("datetime type:LONG pos:0")，应该返回null，因为那样与仅针对字段名称调用get("datetime")不同。

这是结合两个循环并按位置访问值的解决方法

for (int pos = 0; itr.hasNext(); pos++) {   
    String nextField = itr.next().toString();
    System.out.printf("field right now at pos:%d is :%s ; the value in the generic record is %s%n", 
        pos, nextField, genericRecord.get(pos));
    binaryObjBuilder.setField(nextField, genericRecord.get(nextField));
}

我不确定binaryObjBuilder会是什么，但是如果您想按名称获取/设置，那么我建议您尝试

String nextField = itr.next().toString();
String fieldname = nextField.split("\\s+")[0];

从avro 1.8.2中的通用记录中获取价值

1 个答案: