Java执行hadoop的基本操作实例代码

public static void uploadInputFile(String localFile) throws IOException{    Configuration conf = new Configuration();    String hdfsPath = "hdfs://localhost:9000/";    String hdfsInput = "hdfs://localhost:9000/user/hadoop/input";    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);    fs.copyFromLocalFile(new Path(localFile), new Path(hdfsInput));    fs.close();    System.out.println("已经上传文件到input文件夹啦");  }

public static void getOutput(String outputfile) throws IOException{    String remoteFile = "hdfs://localhost:9000/user/hadoop/output/part-r-00000";    Path path = new Path(remoteFile);    Configuration conf = new Configuration();    String hdfsPath = "hdfs://localhost:9000/";    FileSystem fs = FileSystem.get(URI.create(hdfsPath),conf);    fs.copyToLocalFile(path, new Path(outputfile));    System.out.println("已经将输出文件保留到本地文件");    fs.close();  }

 public static void deleteOutput() throws IOException{    Configuration conf = new Configuration();    String hdfsOutput = "hdfs://localhost:9000/user/hadoop/output";    String hdfsPath = "hdfs://localhost:9000/";    Path path = new Path(hdfsOutput);    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);    fs.deleteOnExit(path);    fs.close();    System.out.println("output文件已经删除");  }

public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable>{    private final static IntWritable one = new IntWritable(1);    private Text word = new Text();    public void map(Object key, Text value, Context context) throws IOException, InterruptedException{      String line = value.toString();      line = line.replace("//", "");      String regex = "性别：</span><span class=/"pt_detail/">(.*?)</span>";      Pattern pattern = Pattern.compile(regex);      Matcher matcher = pattern.matcher(line);      while(matcher.find()){        String term = matcher.group(1);        word.set(term);        context.write(word, one);      }    }  }  public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable>{    private IntWritable result = new IntWritable();    public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException{      int sum = 0;      for(IntWritable val :values){        sum+= val.get();      }      result.set(sum);      context.write(key, result);    }  }

public static void runMapReduce(String[] args) throws Exception {    Configuration conf = new Configuration();    String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();    if(otherArgs.length != 2){      System.err.println("Usage: wordcount<in> <out>");      System.exit(2);    }    Job job = new Job(conf, "word count");    job.setJarByClass(WordCount.class);    job.setMapperClass(TokenizerMapper.class);    job.setCombinerClass(IntSumReducer.class);    job.setReducerClass(IntSumReducer.class);    job.setOutputKeyClass(Text.class);    job.setOutputValueClass(IntWritable.class);    FileInputFormat.addInputPath(job, new Path(otherArgs[0]));    FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));    System.out.println("mapReduce 执行完毕！");    System.exit(job.waitForCompletion(true)?0:1);  }