I-List is a very helpful links share platform to share your collected links.
It provides an user friendly interface to you for sharing some kind of links.
I’ve found that there are two collections which is very helpful for some people whose subjects are for studying and implementation in statistics, accounting and computer science.
1. List of Free Accounting Software : For business/accounting area.
2. List of Free Statistical Software : For statistics area.
Hadoop 2.x is developed from hadoop-1.x, with the significant features over hadoop-1.x:
Hadoop 0.23.x is a trunk which contains:
Hadoop 1.x is developed from hadoop 0.20-security code support for:
REST 把軟體視為 "資源"(Resource)，以 URL (Uniform Resource Locator) 定位資源所在處。資源的使用者則藉由 HTTP 協定中所定義的"方法"(method)操作資源。REST 所稱的軟體，其實是資料與資料處理方法的包裝，也就是 OOP 中的 "個體"、"物件"。同時在 HTTP 中，也定義了四種基本方法，即 GET, POST, PUT, DELETE。以上四種基本方法大致上對應了四種資料處理動作，即 Create, Read, Update, Delete (CRUD) 有興趣的讀者，可以自行看看原文解釋。| SVN(Subversion Control System) | Google Docs | |
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import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import java.io.DataInput;
import java.io.DataOutput;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.hadoop.mapred.lib.db.DBWritable;
import org.apache.hadoop.mapred.lib.IdentityReducer;
import org.apache.hadoop.mapred.lib.db.DBConfiguration;
import org.apache.hadoop.mapred.lib.db.DBOutputFormat;
import org.apache.hadoop.mapred.lib.db.DBInputFormat;
/*
MySQL DB Schema:
DROP TABLE IF EXISTS `WordCount`.`Counting`;
CREATE TABLE `WordCount`.`Counting` (
`name` char(48) default NULL,
`count` int(11) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
*/
public class DBWordCount {
// Output Record Object
static class WordCountInfoRecord implements Writable, DBWritable
{
public String name;
public int count;
public WordCountInfoRecord() {
}
public WordCountInfoRecord(String str, int c)
{
this.name = str;
this.count = c;
}
public void readFields(DataInput in) throws IOException {
this.name = Text.readString(in);
this.count = in.readInt();
}
public void write(DataOutput out) throws IOException {
Text.writeString(out, this.name);
out.writeInt(this.count);
}
public void readFields(ResultSet result) throws SQLException {
this.name = result.getString(1);
this.count = result.getInt(2);
}
public void write(PreparedStatement stmt) throws SQLException {
stmt.setString(1, this.name);
stmt.setInt(2, this.count);
}
public String toString() {
return new String(this.name + " " + this.count);
}
}
public static class Map extends MapReduceBase implements Mapper<LongWritable, IntWritable,Text,IntWritable>
{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException
{
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
word.set(tokenizer.nextToken());
output.collect(word, one);
}
}
}
public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, WordCountInfoRecord, NullWritable>
{
public void reduce(Text key, Iterator<intwritable> values, OutputCollector<
WordCountInfoRecord, NullWritable=""> output, Reporter reporter) throws IOException
{
int sum = 0;
while (values.hasNext()) {
sum += values.next().get();
}
// Output Data into MySQL
output.collect(new WordCountInfoRecord(key.toString(),sum), NullWritable.get());
}
}
public static void main(String[] args) throws Exception
{
// The following is basic wordcount
JobConf conf = new JobConf(DBWordCount.class);
conf.setJobName("MySQL DB Wordcount");
Class.forName("com.mysql.jdbc.Driver");
conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(DBOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path(args[0]));
// Setup MySQL Connection , default account:root , no password
String[] MyDBPath={"jdbc:mysql://localhost:3306/WordCount","你的帳號", "你的密碼"};
DBConfiguration.configureDB(conf, "com.mysql.jdbc.Driver",MyDBPath[0], MyDBPath[1], MyDBPath[2]);
// Setup Output MySQL Format
DBOutputFormat.setOutput(conf, "Counting","name", "count");
// Set Mapper and Reducer Class
conf.setMapperClass(Map.class);
//conf.setCombinerClass(Reduce.class);
conf.setReducerClass(Reduce.class);
// I've tried all combinations , but the bug still happen.
conf.setMapOutputKeyClass(Text.class);
conf.setMapOutputValueClass(IntWritable.class);
conf.setOutputKeyClass(WordCountInfoRecord.class);
conf.setOutputValueClass(NullWritable.class);
JobClient.runJob(conf);
}
}
4. 輸入以下指令：# Author: Jyun-Yao Huang (allen501pc@gmail.com)## Set up class path.CLASSPATH=/opt/hadoop/hadoop-0.20.2-ant.jar:/opt/hadoop/hadoop-0.20.2-tools.jar:/opt/hadoop/hadoop-0.20.2-core.jar:/opt/hadoop/lib/mysql-connector-java-5.1.16-bin.jar:./## Set up src files.SRC = DBWordCount.java## Set up class files.OBJ = $(SRC:.java=.class)## Set up jar file.JAR_FILE = DBWordCount.jar## Set up main function.MAIN_FUNC = DBWordCountall: $(OBJ)jar -cvf $(JAR_FILE) DBWordCount*.classmake help%.class: %.javajavac -classpath $(CLASSPATH) $<clean:hadoop fs -rmr outputcleanall:rm *.class *.jarhadoop fs -rmr outputrun:hadoop jar $(JAR_FILE) $(MAIN_FUNC) input/input.txthelp:@echo "==============HELP====================="@echo "make run"@echo "=====END================"
