Question

以下是我的目录结构

  project
     |____src/rdfformatter.java
     |
     pom.xml

所以只有一个档案...... 现在，以下是我的代码：

package org.rdf;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import com.hp.hpl.jena.rdf.model.*;

import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Mapper.Context;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.rdf.RdfWritable;

public class RdfFormatter extends Configured implements Tool {
   // some foo bar

  public static void main(String [] args){
      //some foo bar
     }


}

以下是我的pom文件：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://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>org.rdf</groupId>
  <artifactId>rdfreader</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>RDF READER</name>
  <!--url>http://maven.apache.org</url-->
  <dependencies>
    <!--dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.8.2</version>
      <scope>test</scope>
    </dependency-->

    <dependency>
        <groupId>commons-cli</groupId>
        <artifactId>commons-cli</artifactId>
        <version>1.2</version>
    </dependency>

     <dependency>
         <groupId>org.apache.jena</groupId>
          <artifactId>apache-jena-libs</artifactId>
          <type>pom</type>
          <version>2.10.1</version>
    <exclusions>
        <exclusion>
        <artifactId>slf4j-log4j12</artifactId>
        <groupId>org.slf4j</groupId>
    </exclusion>
    <exclusion>
        <artifactId>commons-codec-1.4</artifactId>
        <groupId>org.commons</groupId>
    </exclusion>
    </exclusions>
    </dependency>

    <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
           <version>3.1</version>
    </dependency>

     <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
     </dependency>

    <dependency>
          <groupId>org.apache.hadoop</groupId>
           <artifactId>hadoop-core</artifactId>
           <version>1.0.3</version>
          <scope>provided</scope>
    </dependency>



  </dependencies>
</project>

当我做的时候

hadoop jar rdfreader-1.0-SNAPSHOT.jar org.rdf.RdfFormatter

我得到了

Exception in thread "main" java.lang.ClassNotFoundException: org.rdf.RdfFormatter
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:149)

我做错了什么？

请注意排除列表..（hadoop有一堆罐子与我正在使用的罐子冲突..否则我收到此错误NoSuchMethodError with slfj4）

Answer 1

你的源代码应该在src / main / java中，而不是直接在/ src下。

然后应根据包装结构进行布局。

所以你的java文件应该在/src/main/java/org/rdf/RdfFormatter.java

Answer 2

您的类在src/main/java的默认目录中没有。所以要么把它放在那里（强烈建议，你应该始终坚持标准，除非有其他明确的理由）或在构建部分指定sourceDirectory。

<build>
    <sourceDirectory>${basedir}/src</sourceDirectory>
</build>

如何编译maven文件？

2 个答案: