HadoopPigLoadfunc

hadoop pig 设计的还是很不错的，可以写 UDF 每一个统计基本上都是要对原始日志进行切分，把想要的一些字段 EXTRACT 提取出来 日志有着基本的模式 "mac:50:A4:C8:D7:10:7D"|"build:5141bc99"|"network:mobile"|"version:2.4.1"|"id:taobao22935952431"| 基本

hadoop pig 设计的还是很不错的，可以写 UDF

每一个统计基本上都是要对原始日志进行切分，把想要的一些字段 EXTRACT 提取出来

日志有着基本的模式

"mac:50:A4:C8:D7:10:7D"|"build:5141bc99"|"network:mobile"|"version:2.4.1"|"id:taobao22935952431"|

基本上是 key, value对，自定义一个 load function ,指定 key,就可以获取 对应的value，在 pig 中可以使用

REGISTER /jar/kload.jar;
AA = LOAD '/log/load.log' USING kload.KoudaiLoader('mac,build') AS (mac,build);
DUMP AA;

输出结果

(50:A4:C8:D7:10:7D,5141bc99)

koudaiLoader是自己实现的一个 Load function,输出为要获取的key,输出为key所对应的 value

    package kload;
    import java.io.IOException;
    import java.util.*;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapreduce.*;
    import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
    import org.apache.pig.*;
    import org.apache.pig.backend.executionengine.ExecException;
    import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.*;
    import org.apache.pig.data.*;
    public class KoudaiLoader  extends LoadFunc{
            protected RecordReader recordReader = null;
            private String fieldDel = "";
            private String[] reqFildList;
            private ArrayList mProtoTuple = null;
            private TupleFactory mTupleFactory = TupleFactory.getInstance();
            private static final int BUFFER_SIZE = 1024;
            public KoudaiLoader() {
            }
            public KoudaiLoader(String delimiter) {
                    this();
                    if(delimiter == null || delimiter.length() == 0){
                            throw new RuntimeException("empty delimiter");
                    }
                    this.reqFildList=delimiter.split(",");
            }
            @Override
            public Tuple getNext() throws IOException {
                    try {
                            Map tmpMap = new HashMap();
                            List lst = new ArrayList();
                            boolean flag = recordReader.nextKeyValue();
                            int i = 0;
                            if (!flag) {
                                    return null;
                            }
                            Text value = (Text) recordReader.getCurrentValue();
                            tmpMap = this.sourceToMap(value.toString());
                            if( tmpMap == null || tmpMap.size() == 0 ){
                                return null;
                            }
                            for (String s :this.reqFildList){
                                String item = tmpMap.get(s); 
                                if(item == null || item.length() == 0){
                                        item = "";
                                }
                                    lst.add(i++, item);
                            }
                            return TupleFactory.getInstance().newTuple(lst);
                    } catch (InterruptedException e) {
                            throw new ExecException("Read data error", PigException.REMOTE_ENVIRONMENT, e);
                    }
            }
            public Map sourceToMap(String pline){
                    String line = pline;
                    int strLen = 0;
                    String[] strArr;
                    String[] strSubArr;
                    Map mapLog = new HashMap();
                    if(pline == null || pline.length() <= 2){
                        return mapLog;
                    }
                    line = line.trim();
                    strLen = line.length();
                    line = line.substring(1,strLen -1);
                    strArr = line.split("\"\\|\"");
                    if(strArr.length == 0){
                        return mapLog;
                    }
                    for(String s:strArr){
                            if(s != null && s.length() != 0){
                                    strSubArr = s.split(":",2); 
                                    if(strSubArr.length == 2){
                                            mapLog.put(strSubArr[0],strSubArr[1]);
                                    }
                            }
                    }
                    return mapLog;
            }
            @Override
            public void setLocation(String s, Job job) throws IOException {
                FileInputFormat.setInputPaths(job, s);
            }
            @Override
            public InputFormat getInputFormat() throws IOException {
                return new PigTextInputFormat();
            }
            @Override
            public void prepareToRead(RecordReader recordReader, PigSplit pigSplit) throws IOException {
                this.recordReader = recordReader;
            }
    }

编译

javac -cp /usr/local/webserver/pig/pig-0.9.2.jar:.  KoudaiLoader.java

打成jar包

jar -cf kload.jar kload

用pig在本地模式下运行

java -cp /usr/local/webserver/pig/pig-0.9.2.jar:/jar/kload.jar org.apache.pig.Main -x local kload.pig

原文地址：Hadoop Pig Loadfunc, 感谢原作者分享。