Bean
package com.zhengkw.rawcomparabletest;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.file.tfile.RawComparable;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
/**
* @ClassName:FlowBean
* @author: zhengkw
* @description:
* @date: 20/03/02下午 8:09
* @version:1.0
* @since: jdk 1.8
*/
public class FlowBean implements Writable {
//上行数据
private Long upFlow;
//下行数据
private Long downFlow;
//总量
private Long totalFlow;
public FlowBean() {
}
public void setUpFlow(Long upFlow) {
this.upFlow = upFlow;
}
public void setDownFlow(Long downFlow) {
this.downFlow = downFlow;
}
public void setTotalFlow(Long totalFlow) {
this.totalFlow = totalFlow;
}
public Long getUpFlow() {
return upFlow;
}
public Long getDownFlow() {
return downFlow;
}
public Long getTotalFlow() {
return totalFlow;
}
public void set(Long upFlow, Long downFlow) {
this.upFlow = upFlow;
this.downFlow = downFlow;
this.totalFlow = upFlow + downFlow;
}
@Override
public void write(DataOutput out) throws IOException {
out.writeLong(upFlow);
out.writeLong(downFlow);
out.writeLong(totalFlow);
}
@Override
public void readFields(DataInput in) throws IOException {
this.upFlow = in.readLong();
this.downFlow = in.readLong();
this.totalFlow = in.readLong();
}
@Override
public String toString() {
return upFlow +
"\t" + downFlow +
"\t" + totalFlow;
}
}
RawComparator实现类
package com.zhengkw.rawcomparabletest;
import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.io.RawComparator;
import java.io.IOException;
/**
* @ClassName:RawComparatorTest
* @author: zhengkw
* @description:
* @date: 20/03/02下午 8:17
* @version:1.0
* @since: jdk 1.8
*/
public class RawComparatorTest implements RawComparator<FlowBean> {
FlowBean flowBean1 = new FlowBean();
FlowBean flowBean2 = new FlowBean();
DataInputBuffer inputBuffer = new DataInputBuffer();
@Override
public int compare(FlowBean o1, FlowBean o2) {
/*
if (o1.getTotalFlow() > o2.getTotalFlow()) {
return -1;
} else if (o1.getTotalFlow() == o2.getTotalFlow()) {
return 0;
} else return 1;
*/
//简化
return - o1.getTotalFlow().compareTo(o2.getTotalFlow());
}
/**
* Compare two objects in binary.
* b1[s1:l1] is the first object, and b2[s2:l2] is the second object.
*
* @param b1 The first byte array.
* @param s1 The position index in b1. The object under comparison's starting index.
* @param l1 The length of the object in b1.
* @param b2 The second byte array.
* @param s2 The position index in b2. The object under comparison's starting index.
* @param l2 The length of the object under comparison in b2.
* @return An integer result of the comparison.
*/
@Override
public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
try {
inputBuffer.reset(b1, s1, l1);
flowBean1.readFields(inputBuffer);
inputBuffer.reset(b2, s2, l2);
flowBean2.readFields(inputBuffer);
} catch (IOException e) {
e.printStackTrace();
}
return compare(flowBean1, flowBean2);
}
}
Mapper
package com.zhengkw.rawcomparabletest;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;
/**
* @ClassName:FlowMapper
* @author: zhengkw
* @description:
* @date: 20/03/02下午 8:08
* @version:1.0
* @since: jdk 1.8
*/
public class FlowMapper extends Mapper<LongWritable, Text, FlowBean, NullWritable> {
FlowBean k = new FlowBean();
@Override
protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String line = value.toString();
String[] info = line.split("\t");
Long upFlow = Long.parseLong(info[info.length - 3]);
Long downFlow = Long.parseLong(info[info.length - 2]);
k.set(upFlow, downFlow);
context.write(k, NullWritable.get());
}
}
Reducer
package com.zhengkw.rawcomparabletest;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import java.io.IOException;
/**
* @ClassName:FlowReducer
* @author: zhengkw
* @description:
* @date: 20/03/02下午 8:09
* @version:1.0
* @since: jdk 1.8
*/
public class FlowReducer extends Reducer<FlowBean, NullWritable, FlowBean, NullWritable> {
@Override
protected void reduce(FlowBean key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException {
context.write(key, NullWritable.get());
}
}
Driver
package com.zhengkw.rawcomparabletest;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import java.io.IOException;
/**
* @ClassName:FlowDriver
* @author: zhengkw
* @description:
* @date: 20/03/02下午 8:09
* @version:1.0
* @since: jdk 1.8
*/
public class FlowDriver {
public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
Path input = new Path("F:\\mrinput\\sort");
Path output = new Path("F:/output5");
Configuration conf = new Configuration();
//conf.set(KeyValueLineRecordReader.KEY_VALUE_SEPERATOR,"\t");
FileSystem fs = FileSystem.get(conf);
if (fs.exists(output)) {
fs.delete(output, true);
}
//反射创建对象
Job job = Job.getInstance(conf);
//给job指定RawComparator比较器
job.setSortComparatorClass(RawComparatorTest.class);
//job.setNumReduceTasks(1);
//设置3个类
job.setJarByClass(FlowDriver.class);
job.setMapperClass(FlowMapper.class);
job.setReducerClass(FlowReducer.class);
//设置2个输入输出
// job.setMapOutputKeyClass(N.class);
// job.setMapOutputValueClass(FlowBean.class);
// 指定最终输出的数据的kv类型
job.setOutputKeyClass(FlowBean.class);
job.setOutputValueClass(NullWritable.class);
// job.setInputFormatClass(KeyValueTextInputFormat.class);
//指定输入输出路径
FileInputFormat.setInputPaths(job, input);
FileOutputFormat.setOutputPath(job, output);
//将job中配置的相关参数，以及job所用的java类所在的jar包， 提交给yarn去运行
boolean result = job.waitForCompletion(true);
System.exit(result ? 0 : 1);
}
}
测试数据
13470253144 180 180 360
13509468723 7335 110349 117684
13560439638 918 4938 5856
13568436656 3597 25635 29232
13590439668 1116 954 2070
13630577991 6960 690 7650
13682846555 1938 2910 4848
13729199489 240 0 240
13736230513 2481 24681 27162
13768778790 120 120 240
13846544121 264 0 264
13956435636 132 1512 1644
13966251146 240 0 240
13975057813 11058 48243 59301
13992314666 3008 3720 6728
15043685818 3659 3538 7197
15910133277 3156 2936 6092
15959002129 1938 180 2118
18271575951 1527 2106 3633
18390173782 9531 2412 11943
84188413 4116 1432 5548
结果
7335 110349 117684
11058 48243 59301
3597 25635 29232
2481 24681 27162
9531 2412 11943
6960 690 7650
3659 3538 7197
3008 3720 6728
3156 2936 6092
918 4938 5856
4116 1432 5548
1938 2910 4848
1527 2106 3633
1938 180 2118
1116 954 2070
132 1512 1644
180 180 360
264 0 264
240 0 240
120 120 240
240 0 240
遇到的问题
1.输出完的结果条数偏少
bug代码
@Override
public int compare(FlowBean o1, FlowBean o2) {
return o1.getTotalFlow() > o2.getTotalFlow()?-1:0;
}
修正以后
@Override
public int compare(FlowBean o1, FlowBean o2) {
if (o1.getTotalFlow() > o2.getTotalFlow()) {
return -1;
} else if (o1.getTotalFlow() == o2.getTotalFlow()) {
return 0;
} else return 1;
}
compato比较条件不够细化。
2.EOFException
原因 :
DataInputStream中的readFully方法中的count<0导致如下图
上图count是调用了InputStream中的read(3个参数)方法来获取的，当没有数据读到（即空行）返回 -1
解决办法：
清洗数据源，删掉空行即可！
注意事项
在Driver类中没设置sortComparator会出现报错
源码出处
若不是writableComparable的实现类，则会出现该异常。因为这个是默认值，所以需要指定sortComparator
//给job指定RawComparator比较器
job.setSortComparatorClass(RawComparatorTest.class);
