多路輸入輸出示例
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本文為您介紹MapReduce的多路輸入輸出示例。
前提條件
已通過快速入門完成測試所需環(huán)境配置。
測試準(zhǔn)備
準(zhǔn)備好測試程序的JAR包,假設(shè)名字為mapreduce-examples.jar,本地存放路徑為MaxCompute客戶端bin目錄下data\resources。
準(zhǔn)備多路輸入輸出的測試表和資源。
創(chuàng)建測試表。
CREATE TABLE wc_in1(key STRING, value STRING); CREATE TABLE wc_in2(key STRING, value STRING); CREATE TABLE mr_multiinout_out1 (key STRING, cnt BIGINT); CREATE TABLE mr_multiinout_out2 (key STRING, cnt BIGINT) PARTITIONED BY (a string, b string); ALTER TABLE mr_multiinout_out2 ADD PARTITION (a='1', b='1'); ALTER TABLE mr_multiinout_out2 ADD PARTITION (a='2', b='2');
添加測試資源。
-- 首次添加忽略-f覆蓋指令。 add jar data\resources\mapreduce-examples.jar -f;
使用Tunnel將MaxCompute客戶端bin目錄下data1.txt,data2.txt分別導(dǎo)入wc_in1和wc_in2表中。
tunnel upload data1.txt wc_in1; tunnel upload data2.txt wc_in2;
導(dǎo)入wc_in1表的數(shù)據(jù)如下。
hello,odps
導(dǎo)入wc_in2表的數(shù)據(jù)如下。
hello,world
測試步驟
在MaxCompute客戶端中執(zhí)行MultipleInOut。
jar -resources mapreduce-examples.jar -classpath data\resources\mapreduce-examples.jar
com.aliyun.odps.mapred.open.example.MultipleInOut wc_in1,wc_in2 mr_multiinout_out1,mr_multiinout_out2|a=1/b=1|out1,mr_multiinout_out2|a=2/b=2|out2;
預(yù)期結(jié)果
作業(yè)成功結(jié)束后,mr_multiinout_out1中的內(nèi)容如下。
+------------+------------+
| key | cnt |
+------------+------------+
| default | 1 |
+------------+------------+
mr_multiinout_out2中的內(nèi)容如下。
+--------+------------+---+---+
| key | cnt | a | b |
+--------+------------+---+---+
| odps | 1 | 1 | 1 |
| world | 1 | 1 | 1 |
| out1 | 1 | 1 | 1 |
| hello | 2 | 2 | 2 |
| out2 | 1 | 2 | 2 |
+--------+------------+---+---+
代碼示例
Pom依賴信息,請參見注意事項(xiàng)。
package com.aliyun.odps.mapred.open.example;
import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedHashMap;
import com.aliyun.odps.data.Record;
import com.aliyun.odps.data.TableInfo;
import com.aliyun.odps.mapred.JobClient;
import com.aliyun.odps.mapred.MapperBase;
import com.aliyun.odps.mapred.ReducerBase;
import com.aliyun.odps.mapred.TaskContext;
import com.aliyun.odps.mapred.conf.JobConf;
import com.aliyun.odps.mapred.utils.InputUtils;
import com.aliyun.odps.mapred.utils.OutputUtils;
import com.aliyun.odps.mapred.utils.SchemaUtils;
/**
* Multi input & output example.
**/
public class MultipleInOut {
public static class TokenizerMapper extends MapperBase {
Record word;
Record one;
@Override
public void setup(TaskContext context) throws IOException {
word = context.createMapOutputKeyRecord();
one = context.createMapOutputValueRecord();
one.set(new Object[] { 1L });
}
@Override
public void map(long recordNum, Record record, TaskContext context)
throws IOException {
for (int i = 0; i < record.getColumnCount(); i++) {
word.set(new Object[] { record.get(i).toString() });
context.write(word, one);
}
}
}
public static class SumReducer extends ReducerBase {
private Record result;
private Record result1;
private Record result2;
@Override
public void setup(TaskContext context) throws IOException {
/**對于不同的輸出需要創(chuàng)建不同的Record,通過Label來區(qū)分。*/
result = context.createOutputRecord();
result1 = context.createOutputRecord("out1");
result2 = context.createOutputRecord("out2");
}
@Override
public void reduce(Record key, Iterator<Record> values, TaskContext context)
throws IOException {
long count = 0;
while (values.hasNext()) {
Record val = values.next();
count += (Long) val.get(0);
}
long mod = count % 3;
if (mod == 0) {
result.set(0, key.get(0));
result.set(1, count);
/**不指定Label,默認(rèn)(default)輸出。*/
context.write(result);
} else if (mod == 1) {
result1.set(0, key.get(0));
result1.set(1, count);
context.write(result1, "out1");
} else {
result2.set(0, key.get(0));
result2.set(1, count);
context.write(result2, "out2");
}
}
@Override
public void cleanup(TaskContext context) throws IOException {
Record result = context.createOutputRecord();
result.set(0, "default");
result.set(1, 1L);
context.write(result);
Record result1 = context.createOutputRecord("out1");
result1.set(0, "out1");
result1.set(1, 1L);
context.write(result1, "out1");
Record result2 = context.createOutputRecord("out2");
result2.set(0, "out2");
result2.set(1, 1L);
context.write(result2, "out2");
}
}
/**將分區(qū)字符串如"ds=1/pt=2"轉(zhuǎn)為Map的形式。*/
public static LinkedHashMap<String, String> convertPartSpecToMap(
String partSpec) {
LinkedHashMap<String, String> map = new LinkedHashMap<String, String>();
if (partSpec != null && !partSpec.trim().isEmpty()) {
String[] parts = partSpec.split("/");
for (String part : parts) {
String[] ss = part.split("=");
if (ss.length != 2) {
throw new RuntimeException("ODPS-0730001: error part spec format: "
+ partSpec);
}
map.put(ss[0], ss[1]);
}
}
return map;
}
public static void main(String[] args) throws Exception {
String[] inputs = null;
String[] outputs = null;
if (args.length == 2) {
inputs = args[0].split(",");
outputs = args[1].split(",");
} else {
System.err.println("MultipleInOut in... out...");
System.exit(1);
}
JobConf job = new JobConf();
job.setMapperClass(TokenizerMapper.class);
job.setReducerClass(SumReducer.class);
job.setMapOutputKeySchema(SchemaUtils.fromString("word:string"));
job.setMapOutputValueSchema(SchemaUtils.fromString("count:bigint"));
/**解析用戶的輸入表字符串。*/
for (String in : inputs) {
String[] ss = in.split("\\|");
if (ss.length == 1) {
InputUtils.addTable(TableInfo.builder().tableName(ss[0]).build(), job);
} else if (ss.length == 2) {
LinkedHashMap<String, String> map = convertPartSpecToMap(ss[1]);
InputUtils.addTable(TableInfo.builder().tableName(ss[0]).partSpec(map).build(), job);
} else {
System.err.println("Style of input: " + in + " is not right");
System.exit(1);
}
}
/**解析用戶的輸出表字符串。*/
for (String out : outputs) {
String[] ss = out.split("\\|");
if (ss.length == 1) {
OutputUtils.addTable(TableInfo.builder().tableName(ss[0]).build(), job);
} else if (ss.length == 2) {
LinkedHashMap<String, String> map = convertPartSpecToMap(ss[1]);
OutputUtils.addTable(TableInfo.builder().tableName(ss[0]).partSpec(map).build(), job);
} else if (ss.length == 3) {
if (ss[1].isEmpty()) {
LinkedHashMap<String, String> map = convertPartSpecToMap(ss[2]);
OutputUtils.addTable(TableInfo.builder().tableName(ss[0]).partSpec(map).build(), job);
} else {
LinkedHashMap<String, String> map = convertPartSpecToMap(ss[1]);
OutputUtils.addTable(TableInfo.builder().tableName(ss[0]).partSpec(map)
.label(ss[2]).build(), job);
}
} else {
System.err.println("Style of output: " + out + " is not right");
System.exit(1);
}
}
JobClient.runJob(job);
}
}
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