Question

我正在编写Pig UDF，并尝试使用Maven将其编译成jar。代码在Eclipse中注册正常，但是当我在Maven中构建它时，我得到一个找不到符号错误，如下所示。我已经检查了openReader方法的方法签名，并且它匹配了我传递它的类，所以我不确定Maven编译出了什么问题。

Dependencies Snippet：

<dependency>
    <groupId>org.apache.hadoop</groupId>
    <artifactId>hadoop-core</artifactId>
    <version>${hadoop.version}</version>
    <exclusions>
        <exclusion>
            <groupId>hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
        </exclusion>
        <exclusion>
            <groupId>net.sf.kosmosfs</groupId>
            <artifactId>kfs</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.eclipse.jdt</groupId>
            <artifactId>core</artifactId>
        </exclusion>
        <exclusion>
            <groupId>net.java.dev.jets3t</groupId>
            <artifactId>jets3t</artifactId>
        </exclusion>
        <exclusion>
            <groupId>oro</groupId>
            <artifactId>oro</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.apache.avro</groupId>
    <artifactId>avro-mapred</artifactId>
    <version>1.7.5</version>
</dependency>
<dependency>
    <groupId>org.apache.avro</groupId>
    <artifactId>avro</artifactId>
    <version>1.7.5</version>
</dependency>

代码段：

import org.apache.avro.file.DataFileReader;
import org.apache.avro.file.FileReader;
import org.apache.avro.file.SeekableInput;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.DatumReader;
import org.apache.avro.mapred.FsInput;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;

protected String getLastRecord(String location) throws IOException {
  Path path = new Path(location);
  Configuration config = new Configuration();
  SeekableInput input = new FsInput(path, config);
  DatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>();
  FileReader<GenericRecord> fileReader = DataFileReader.openReader(input, reader);
  Iterator<GenericRecord> itr = fileReader.iterator(); 

  long initialPosition = input.tell();
  itr.next();
  long newPosition = input.tell();

  input.seek(input.length() - (initialPosition - newPosition));
  return itr.next().get("id").toString();
};

错误：

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project newscred-recsys-udfs: Compilation failure
[ERROR] /Users/andrew/Code/recommender/hadoop/newscred_recsys/udfs/java/src/main/java/com/mortardata/newscred/recsys/SqoopAvroLoader.java:[104,64] cannot find symbol
[ERROR] symbol:   method openReader(org.apache.avro.file.SeekableInput,org.apache.avro.io.DatumReader<org.apache.avro.generic.GenericRecord>)
[ERROR] location: class org.apache.avro.file.DataFileReader
[ERROR] -> [Help 1]

Answer 1

应该清理项目。项目 - ＆gt;清洁

Answer 2

显然，org.apache.avro的jar有一组不同于Apache网站发布的jar的方法，导致不匹配。

Maven无法找到符号，但独立构建工作

2 个答案: