2-1、二次排序代码

小咪咪 2022-08-04 13:45 115阅读 0赞

**1、输入数据：**

[hadoop@hadoop ~]$ hdfs dfs -text /user/hadoop/secondarysort.txt
    3       5
    5       89
    7       63
    5       56
    3       9
    3       1
    7       26
    7       45
    7       4
    5       18
    5       23
    7       63
    3       24
    [hadoop@hadoop ~]$

**2、代码：**

package secondarySort;
    
    
    import java.io.DataInput;
    import java.io.DataOutput;
    import java.io.IOException;
    import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.Path;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.LongWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.io.WritableComparable;
    import org.apache.hadoop.io.WritableComparator;
    import org.apache.hadoop.mapreduce.Job;
    import org.apache.hadoop.mapreduce.Mapper;
    import org.apache.hadoop.mapreduce.Partitioner;
    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;
    
    
    public class SecondarySort_Demo {
    	//自己定义的key类应该实现WritableComparable接口  
    	public static class IntPair implements WritableComparable<IntPair>{
    		
    		int first;
    		int second;
    		public void set(int left,int right){
    			first=left;
    			second=right;
    		}
    		public int getFirst(){
    			return first;
    		}
    		public int getSecond(){
    			return second;
    		}
    		//序列化，将IntPair转化成使用流传送的二进制  
    		public void write(DataOutput out) throws IOException {
    			out.writeInt(first);
    			out.writeInt(second);
    		}
    		//反序列化，从流中的二进制转换成IntPair
    		public void readFields(DataInput in) throws IOException {
    			first=in.readInt();
    			second=in.readInt();
    		}
    		//key的比较  
    		public int compareTo(IntPair o) {
    			if(first!=o.first){
    				return first<o.first ? -1:1;
    			}else if(second!=o.second){
    				return second<o.second ? -1:1;
    			}else{
    				return 0;
    			}
    		
    		}
    		//新定义类应该重写的两个方法  
    		public int hashCode(){
    			return first*157+second;
    		}
    		
    		public boolean equals(Object right){
    			if(right==null)
    				return false;
    			if(this==right)
    				return true;
    			if(right instanceof IntPair){
    				IntPair r=(IntPair) right;
    				return r.first==first&&r.second==second;
    			}else {
    				return false;
    			}
    		}
    	}
    	 /** 
         * 分区函数类。根据first确定Partition。 
         */
    	public static class FirstPartitioner extends Partitioner<IntPair, IntWritable>{
    		@Override
    		public int getPartition(IntPair key, IntWritable value,
    				int numPartitions) {
    			return Math.abs(key.getFirst()*127) % numPartitions;
    		}
    	}
    	/** 
         * 分组函数类。只要first相同就属于同一个组。 
         */  
    	/*//第一种方法，实现接口RawComparator
    	public static class GroupingCpmparator implements RawComparator<IntPair>{
    
    
    		public int compare(IntPair o1, IntPair o2) {
    			int l=o1.getFirst();
    			int r=o2.getFirst();
    			return l == r ? 0:(l<r ? -1:1);
    		}
    		 //一个字节一个字节的比，直到找到一个不相同的字节，然后比这个字节的大小作为两个字节流的大小比较结果。
    		public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
    			return WritableComparator.compareBytes(b1, s1, Integer.SIZE/8, b2, s2, Integer.SIZE/8);
    		}
    	}*/
    	//第二种方法，继承WritableComparator
    	public static class GroupingComparator extends WritableComparator{
    		protected GroupingComparator(){
    			super(IntPair.class,true);
    		}
    		
    		@SuppressWarnings("rawtypes")
    		//Compare two WritableComparables. 
    		public int compare(WritableComparable w1,WritableComparable w2){
    			IntPair ip1=(IntPair) w1;
    			IntPair ip2=(IntPair) w2;
    			int l=ip1.getFirst();
    			int r=ip2.getFirst();
    			return l==r?1:(l<r?-1:1);
    		}
    	}
    	// 自定义map 
    	public static class MyMap extends Mapper<LongWritable, Text, IntPair, IntWritable>{
    		private final IntPair intkey=new IntPair();
    		private final IntWritable intvalue=new IntWritable();
    		@Override
    		protected void map(LongWritable key, Text value,Context context)
    				throws IOException, InterruptedException {
    			String line=value.toString();
    			String[] splited=line.split("\t");
    			intkey.set(Integer.parseInt(splited[0]), Integer.parseInt(splited[1]));
    			intvalue.set(Integer.parseInt(splited[1]));
    			context.write(intkey, intvalue);
    		}
    	}
    	// 自定义reduce  
    	public static class MyReduce extends Reducer<IntPair, IntWritable, Text, IntWritable>{
    		private final Text left =new Text();
    	//	private static final Text SEPARATOR =new Text("========================");
    		@Override
    		protected void reduce(IntPair k2, Iterable<IntWritable> v2s,Context context)
    				throws IOException, InterruptedException {
    	//		context.write(SEPARATOR, null);
    			left.set(Integer.toString(k2.getFirst()));
    			for (IntWritable val : v2s) {
    				context.write(left, val);
    			}
    		}
    	}
    	
    	public static void main(String[] args) throws Exception{
    		Configuration conf = new Configuration();  
            // 实例化一道作业  
            Job job=Job.getInstance(conf, SecondarySort_Demo.class.getSimpleName());
            job.setJarByClass(SecondarySort_Demo.class);  
            // Mapper类型  
            job.setMapperClass(MyMap.class);  
            // 不再需要Combiner类型，因为Combiner的输出类型<Text, IntWritable>对Reduce的输入类型<IntPair, IntWritable>不适用  
            //job.setCombinerClass(Reduce.class);  
            // Reducer类型  
            job.setReducerClass(MyReduce.class);  
            // 分区函数  
            job.setPartitionerClass(FirstPartitioner.class);  
            // 分组函数  
            job.setGroupingComparatorClass(GroupingComparator.class);  
              
            // map 输出Key的类型  
            job.setMapOutputKeyClass(IntPair.class);  
            // map输出Value的类型  
            job.setMapOutputValueClass(IntWritable.class);  
            // rduce输出Key的类型，是Text，因为使用的OutputFormatClass是TextOutputFormat  
            job.setOutputKeyClass(Text.class);  
            // rduce输出Value的类型  
            job.setOutputValueClass(IntWritable.class);  
              
            // 将输入的数据集分割成小数据块splites，同时提供一个RecordReder的实现。  
            job.setInputFormatClass(TextInputFormat.class);  
            // 提供一个RecordWriter的实现，负责数据输出。  
            job.setOutputFormatClass(TextOutputFormat.class);  
              
            // 输入hdfs路径  
            FileInputFormat.setInputPaths(job, args[0]);  
            // 输出hdfs路径  
            FileOutputFormat.setOutputPath(job, new Path(args[1]));  
            // 提交job  
    //        System.exit(job.waitForCompletion(true) ? 0 : 1);  
            job.waitForCompletion(true); 
    	}
    	
    }

**3、打包执行命令：**

hadoop jar secondarysort.jar /user/hadoop/secondarysort.txt /user/hadoop/output

**4、结果输出文件目录：**

[hadoop@hadoop ~]$ hdfs dfs -ls /user/hadoop/output
    Found 77 items
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/_SUCCESS
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00000
    -rw-r--r--   3 hadoop supergroup         17 2015-08-30 17:22 /user/hadoop/output/part-r-00001
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00002
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00003
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00004
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00005
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00006
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00007
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00008
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00009
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00010
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00011
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00012
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00013
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00014
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00015
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00016
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00017
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00018
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00019
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00020
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00021
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00022
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00023
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00024
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00025
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00026
    -rw-r--r--   3 hadoop supergroup         20 2015-08-30 17:22 /user/hadoop/output/part-r-00027
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00028
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00029
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00030
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00031
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00032
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00033
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00034
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00035
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00036
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00037
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00038
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00039
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00040
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00041
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00042
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00043
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00044
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00045
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00046
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00047
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00048
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00049
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00050
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00051
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00052
    -rw-r--r--   3 hadoop supergroup         24 2015-08-30 17:22 /user/hadoop/output/part-r-00053
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00054
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00055
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00056
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00057
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00058
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00059
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00060
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00061
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00062
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00063
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00064
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00065
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00066
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00067
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00068
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00069
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00070
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00071
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00072
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00073
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00074
    -rw-r--r--   3 hadoop supergroup          0 2015-08-30 17:22 /user/hadoop/output/part-r-00075

**5、排序完数据：**

[hadoop@hadoop ~]$ hdfs dfs -text /user/hadoop/output/part-r-00001
    3       1
    3       5
    3       9
    3       24
    [hadoop@hadoop ~]$ hdfs dfs -text /user/hadoop/output/part-r-00027
    5       18
    5       23
    5       56
    5       89
    [hadoop@hadoop ~]$ hdfs dfs -text /user/hadoop/output/part-r-00053
    7       4
    7       26
    7       45
    7       63
    7       63
    [hadoop@hadoop ~]$