spark java api 调用时报

java.lang.ClassNotFoundException: JavaWordCount$1

在调用spark给的例子中，我们会碰到提交运行的时候会报空指针问题。那时因为spark集群中找不到你制定的class，所以我们需要手动的将包添加到当前的job中。以JavaWordCount为例，修改后的代码如下：

备注：在运行的参数中需要设置==》spark://localhost:7077  hdfs://localhost:9000/input/test.txt  hdfs://localhost:9000/input/result.txt

/** Licensed to the Apache Software Foundation (ASF) under one or more* contributor license agreements.  See the NOTICE file distributed with* this work for additional information regarding copyright ownership.* The ASF licenses this file to You under the Apache License, Version 2.0* (the "License"); you may not use this file except in compliance with* the License.  You may obtain a copy of the License at**    http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.*/import java.util.Arrays;import java.util.regex.Pattern;import org.apache.spark.api.java.JavaPairRDD;import org.apache.spark.api.java.JavaRDD;import org.apache.spark.api.java.JavaSparkContext;import org.apache.spark.api.java.function.FlatMapFunction;import org.apache.spark.api.java.function.Function2;import org.apache.spark.api.java.function.PairFunction;import scala.Tuple2;public final class JavaWordCount {  private static final Pattern SPACE = Pattern.compile(" ");  public static void main(String[] args) throws Exception {    if (args.length < 2) {      System.err.println("Usage: JavaWordCount <master> <file>");      System.exit(1);    }    JavaSparkContext ctx = new JavaSparkContext(args[0], "JavaWordCount",        System.getenv("SPARK_HOME"), JavaSparkContext.jarOfClass(JavaWordCount.class));    ctx.addJar("/home/hadoop/Desktop/JavaSparkT.jar");    JavaRDD<String> lines = ctx.textFile(args[1], 1);       JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {      @Override      public Iterable<String> call(String s) {        return Arrays.asList(SPACE.split(s));      }    });       JavaPairRDD<String, Integer> ones = words.map(new PairFunction<String, String, Integer>() {      @Override      public Tuple2<String, Integer> call(String s) {        return new Tuple2<String, Integer>(s, 1);      }    });       JavaPairRDD<String, Integer> counts = ones.reduceByKey(new Function2<Integer, Integer, Integer>() {      @Override      public Integer call(Integer i1, Integer i2) {        return i1 + i2;      }    });    counts.saveAsTextFile(args[2]);//    counts.s    /*List<Tuple2<String, Integer>> output = counts.collect();    for (Tuple2<?,?> tuple : output) {      System.out.println(tuple._1() + ": " + tuple._2());    }*/    System.exit(0);  }}