1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
| AMMapper:
package ArrayMultiply;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;
public class AMMapper extends Mapper<LongWritable, Text,Text, Text> {
private String flag = null;
//A:4*3 B:3*3
private int m = 4;//矩阵A的行数
private int p = 3;//矩阵B的列数
@Override
protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String[] fields = value.toString().split(",");
if(fields[0].equals("a")){
for(int i = 1;i<=p;i++){
context.write(new Text(fields[1] + "," + i),new Text("a," + fields[2] + "," +fields[3]));
}
}else if(fields[0].equals("b")){
for(int i = 1;i<=m;i++){
context.write(new Text(i + "," + fields[2]),new Text("b,"+ fields[1] + "," + fields[3]));
}
}
}
}
AMReducer:
package ArrayMultiply;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
public class AMReducer extends Reducer<Text, Text,Text, IntWritable> {
@Override
protected void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
HashMap<String,String> mapA = new HashMap<>();
HashMap<String,String> mapB = new HashMap<>();
for (Text value : values) {
String[] val = value.toString().split(",");
if("a".equals(val[0])){
mapA.put(val[1],val[2]);
}else if("b".equals(val[0])){
mapB.put(val[1],val[2]);
}
}
int result = 0;
Iterator<String> mKeys = mapA.keySet().iterator();
while(mKeys.hasNext()){
String mkey = mKeys.next();
if(mapB.get(mkey) == null)
continue;
result += Integer.parseInt(mapA.get(mkey))
* Integer.parseInt(mapB.get(mkey));
}
context.write(key,new IntWritable(result));
}
}
|
