Home > Database > Mysql Tutorial > body text

Hadoop MapRduce 重写DBOutputFormat更新mysql数据库_MySQL

WBOY
Release: 2016-06-01 13:10:06
Original
1129 people have browsed it

 

在http://blog.csdn.net/sunflower_cao/article/details/28266939  写过可以通过继承 Writable, DBWritable实现在reduce过程中讲结果写入到mysql数据库里边,但是一直有一个问题就是只能实现insert  没法去更新已经存在的数据,这就导致不同的mapreduce程序获得的数据只能插入到不同的数据库中 在使用的时候需要建立view或者使用复杂的sql语句去查询,今天调查了下,发现可以通过重写DBOutputFormat

 

上代码:

TblsWritable.java

import java.io.DataInput;import java.io.DataOutput;import java.io.IOException;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import org.apache.hadoop.io.Writable;import org.apache.hadoop.mapreduce.lib.db.DBWritable;/** * 重写DBWritable *  * @author caozw TblsWritable需要向mysql中写入数据 */public  class TblsWritable implements Writable, DBWritable {	String initTime;	String new_android_user;	String new_ios_user;	String new_total_user;	String iosUserTotal;	String androidUserTotal;	String userTotal;	public TblsWritable() {	}	public TblsWritable(String initTime, String new_android_user,			String new_ios_user, String new_total_user,			String iosUserTotal, String androidUserTotal, String userTotal) {		this.initTime = initTime;		this.new_android_user = new_android_user;		this.new_ios_user = new_ios_user;		this.new_total_user = new_total_user;		this.iosUserTotal = iosUserTotal;		this.androidUserTotal = androidUserTotal;		this.userTotal = userTotal;	}	@Override	public void write(PreparedStatement statement) throws SQLException {		statement.setString(1, this.new_android_user);		statement.setString(2, this.new_ios_user);		statement.setString(3, this.new_total_user);		statement.setString(4, this.androidUserTotal);		statement.setString(5, this.iosUserTotal);		statement.setString(6, this.userTotal);		statement.setString(7, this.initTime);	}	@Override	public void readFields(ResultSet resultSet) throws SQLException {		this.new_android_user = resultSet.getString(1);		this.new_ios_user = resultSet.getString(2);		this.new_total_user = resultSet.getString(3);		this.androidUserTotal = resultSet.getString(4);		this.iosUserTotal = resultSet.getString(5);		this.userTotal = resultSet.getString(6);		this.initTime = resultSet.getString(7);	}	@Override	public void write(DataOutput out) throws IOException {		out.writeUTF(this.new_android_user);		out.writeUTF(this.new_ios_user);		out.writeUTF(this.new_total_user);		out.writeUTF(this.androidUserTotal);		out.writeUTF(this.iosUserTotal);		out.writeUTF(this.userTotal);		out.writeUTF(this.initTime);	}	@Override	public void readFields(DataInput in) throws IOException {		this.new_android_user = in.readUTF();		this.new_ios_user = in.readUTF();		this.new_total_user = in.readUTF();		this.androidUserTotal = in.readUTF();		this.iosUserTotal = in.readUTF();		this.userTotal = in.readUTF();		this.initTime = in.readUTF();	}	public String toString() {		return new String(this.initTime + " " + this.new_android_user + " "				+ this.new_ios_user + " " + this.new_total_user + " "				+ this.androidUserTotal + " " + this.iosUserTotal + " "				+ this.userTotal);	}}
Copy after login


WriteDataToMysql.java

import java.io.IOException;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Iterator;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IntWritable;import org.apache.hadoop.io.LongWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapreduce.Job;import org.apache.hadoop.mapreduce.Mapper;import org.apache.hadoop.mapreduce.Reducer;import org.apache.hadoop.mapreduce.lib.db.DBConfiguration;import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;/** * 将mapreduce的结果数据写入mysql中 *  * @author caozw */public class WriteDataToMysql {	public static String[] fieldNames = { "INITTIME", "NEW_ANDROID_USER",			"NEW_IOS_USER", "NEW_USER_TOTAL", "TOTAL_ANDROID_USER",			"TOTAL_IOS_USER", "TOTAL_USER" };	public static String table = "USER_INFO_STATIC";		public static class ConnMysqlMapper extends			Mapper<longwritable text intwritable> {		enum Counter {			LINESKIP,		}		private final static IntWritable one = new IntWritable(1);		private final static IntWritable zero = new IntWritable(0);		public void map(LongWritable key, Text value, Context context)				throws IOException, InterruptedException {			try {				String line = value.toString();				String[] strings = line.split("/t");				String initTime = strings[1];				String devType = strings[4];				if (initTime.length() == 19) {					SimpleDateFormat sdf = new SimpleDateFormat(							"yyyy-MM-dd HH:mm:ss");					Date date = sdf.parse(initTime);					if ("1".equals(devType)) {						context.write(new Text(initTime.substring(0, 10)), one);						context.write(new Text(initTime.substring(0, 10)), zero);					}				} else {					// System.err.println(initTime);					context.getCounter(Counter.LINESKIP).increment(1);				}				// } catch (ArrayIndexOutOfBoundsException e) {			} catch (ArrayIndexOutOfBoundsException e) {				context.getCounter(Counter.LINESKIP).increment(1);				return;			} catch (ParseException e) {				context.getCounter(Counter.LINESKIP).increment(1);				return;			}		}	}	public static class ConnMysqlReducer extends			Reducer<text intwritable tblswritable> {		static int iosUserTotal = 0;		static int androidUserTotal = 0;		public void reduce(Text key, Iterable<intwritable> values,				Context context) throws IOException, InterruptedException {			int android = 0;			int ios = 0;			int total = 0;			for (Iterator<intwritable> itr = values.iterator(); itr.hasNext();) {				total++;				if (0 == itr.next().get()) {					android++;				} else {					ios++;				}			}			iosUserTotal += ios;			androidUserTotal += android;			/*			 * System.err.println(key.toString() + ":" + String.valueOf(android)			 * + ":" + String.valueOf(ios) + ":" + String.valueOf(total));			 */			context.write(					new TblsWritable(key.toString(), String.valueOf(android),							String.valueOf(ios), String.valueOf(total), String									.valueOf(androidUserTotal), String									.valueOf(iosUserTotal), String									.valueOf(androidUserTotal + iosUserTotal)),					null);		}	}	public static void main(String args[]) throws IOException,			InterruptedException, ClassNotFoundException {		Configuration conf = new Configuration();		DBConfiguration.configureDB(conf, "com.mysql.jdbc.Driver",				"jdbc:mysql://127.0.0.1:3306/XINGXUNTONG", "hadoop", "123456");		Job job = new Job(conf, "test mysql connection");		job.setJarByClass(WriteDataToMysql.class);		job.setMapperClass(ConnMysqlMapper.class);		job.setReducerClass(ConnMysqlReducer.class);		job.setOutputKeyClass(Text.class);		job.setOutputValueClass(IntWritable.class);		job.setSpeculativeExecution(false);		job.setInputFormatClass(TextInputFormat.class);		job.setOutputFormatClass(MysqlDBOutputFormat.class);		//job.setOutputFormatClass(DBOutputFormat.class);				FileInputFormat.addInputPath(job, new Path(args[0]));		// DBOutputFormat.setOutput(job, "test", "initTime", "new_user_total");		//DBOutputFormat.setOutput(job, table, fieldNames);		MysqlDBOutputFormat.setOutput(job, table, fieldNames);		System.exit(job.waitForCompletion(true) ? 0 : 1);	}}</intwritable></intwritable></text></longwritable>
Copy after login


MysqlDBOutputFormat.java

/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements.  See the NOTICE file * distributed with this work for additional information * regarding copyright ownership.  The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License.  You may obtain a copy of the License at * *     http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import java.io.IOException;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.apache.hadoop.classification.InterfaceAudience;import org.apache.hadoop.classification.InterfaceStability;import org.apache.hadoop.mapreduce.Job;import org.apache.hadoop.mapreduce.JobContext;import org.apache.hadoop.mapreduce.OutputCommitter;import org.apache.hadoop.mapreduce.OutputFormat;import org.apache.hadoop.mapreduce.RecordWriter;import org.apache.hadoop.mapreduce.TaskAttemptContext;import org.apache.hadoop.mapreduce.lib.db.DBConfiguration;import org.apache.hadoop.mapreduce.lib.db.DBWritable;import org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;import org.apache.hadoop.util.StringUtils;/** * A OutputFormat that sends the reduce output to a SQL table. * <p>  * {@link MysqlDBOutputFormat} accepts <key> pairs, where  * key has a type extending DBWritable. Returned {@link RecordWriter}  * writes <b>only the key</b> to the database with a batch SQL query.   *  */@InterfaceAudience.Public@InterfaceStability.Stablepublic class MysqlDBOutputFormat<k extends dbwritable v> extends OutputFormat<k> {  private static final Log LOG = LogFactory.getLog(MysqlDBOutputFormat.class);  public void checkOutputSpecs(JobContext context)       throws IOException, InterruptedException {}  public OutputCommitter getOutputCommitter(TaskAttemptContext context)       throws IOException, InterruptedException {    return new FileOutputCommitter(FileOutputFormat.getOutputPath(context),                                   context);  }  /**   * A RecordWriter that writes the reduce output to a SQL table   */  @InterfaceStability.Evolving  public class DBRecordWriter       extends RecordWriter<k v> {    private Connection connection;    private PreparedStatement statement;    public DBRecordWriter() throws SQLException {    }    public DBRecordWriter(Connection connection        , PreparedStatement statement) throws SQLException {      this.connection = connection;      this.statement = statement;      this.connection.setAutoCommit(false);    }    public Connection getConnection() {      return connection;    }        public PreparedStatement getStatement() {      return statement;    }        /** {@inheritDoc} */    public void close(TaskAttemptContext context) throws IOException {      try {        statement.executeBatch();        connection.commit();      } catch (SQLException e) {        try {          connection.rollback();        }        catch (SQLException ex) {          LOG.warn(StringUtils.stringifyException(ex));        }        throw new IOException(e.getMessage());      } finally {        try {          statement.close();          connection.close();        }        catch (SQLException ex) {          throw new IOException(ex.getMessage());        }      }    }    /** {@inheritDoc} */    public void write(K key, V value) throws IOException {      try {        key.write(statement);        statement.addBatch();      } catch (SQLException e) {        e.printStackTrace();      }    }  }  /**   * Constructs the query used as the prepared statement to insert data.   *    * @param table   *          the table to insert into   * @param fieldNames   *          the fields to insert into. If field names are unknown, supply an   *          array of nulls.   */  public String constructQuery(String table, String[] fieldNames) {		if (fieldNames == null) {			throw new IllegalArgumentException(					"Field names may not be null");		}		StringBuilder query = new StringBuilder();		query.append("UPDATE ").append(table);		System.err.println("fieldNames.length:" + fieldNames.length);		if (fieldNames.length > 0) {			query.append(" SET ");			query.append(fieldNames[1] + " = ?");			query.append("," + fieldNames[2] + " = ?");			query.append("," + fieldNames[3] + " = ?");			query.append("," + fieldNames[4] + " = ?");			query.append("," + fieldNames[5] + " = ?");			query.append("," + fieldNames[6] + " = ?");			query.append(" WHERE ");			query.append(fieldNames[0] + " = ?");			System.err.println(query.toString());			return query.toString();		} else {			return null;		}  }  /** {@inheritDoc} */  public RecordWriter<k v> getRecordWriter(TaskAttemptContext context)       throws IOException {    DBConfiguration dbConf = new DBConfiguration(context.getConfiguration());    String tableName = dbConf.getOutputTableName();    String[] fieldNames = dbConf.getOutputFieldNames();        if(fieldNames == null) {      fieldNames = new String[dbConf.getOutputFieldCount()];    }        try {      Connection connection = dbConf.getConnection();      PreparedStatement statement = null;        statement = connection.prepareStatement(                    constructQuery(tableName, fieldNames));      return new DBRecordWriter(connection, statement);    } catch (Exception ex) {      throw new IOException(ex.getMessage());    }  }  /**   * Initializes the reduce-part of the job with    * the appropriate output settings   *    * @param job The job   * @param tableName The table to insert data into   * @param fieldNames The field names in the table.   */  public static void setOutput(Job job, String tableName,       String... fieldNames) throws IOException {    if(fieldNames.length > 0 && fieldNames[0] != null) {      DBConfiguration dbConf = setOutput(job, tableName);      dbConf.setOutputFieldNames(fieldNames);    } else {      if (fieldNames.length > 0) {        setOutput(job, tableName, fieldNames.length);      }      else {         throw new IllegalArgumentException(          "Field names must be greater than 0");      }    }  }    /**   * Initializes the reduce-part of the job    * with the appropriate output settings   *    * @param job The job   * @param tableName The table to insert data into   * @param fieldCount the number of fields in the table.   */  public static void setOutput(Job job, String tableName,       int fieldCount) throws IOException {    DBConfiguration dbConf = setOutput(job, tableName);    dbConf.setOutputFieldCount(fieldCount);  }    private static DBConfiguration setOutput(Job job,      String tableName) throws IOException {    job.setOutputFormatClass(MysqlDBOutputFormat.class);    job.setReduceSpeculativeExecution(false);    DBConfiguration dbConf = new DBConfiguration(job.getConfiguration());        dbConf.setOutputTableName(tableName);    return dbConf;  }}</k></k></k></k></key></p>
Copy after login


MysqlDBOutputFormat.java是将hadoop源码里边的DBOutputFormat.java拿过来重写了里边的constructQuery的方法,在生成sql语句的时候产生update的sql语句来实现的

DBOutputFormat.java里边的constructQuery

public String constructQuery(String table, String[] fieldNames) {    if(fieldNames == null) {      throw new IllegalArgumentException("Field names may not be null");    }    StringBuilder query = new StringBuilder();    query.append("INSERT INTO ").append(table);    if (fieldNames.length > 0 && fieldNames[0] != null) {      query.append(" (");      for (int i = 0; i <p><br>重写后:</p><pre class="brush:php;toolbar:false">public String constructQuery(String table, String[] fieldNames) {		if (fieldNames == null) {			throw new IllegalArgumentException(					"Field names may not be null");		}		StringBuilder query = new StringBuilder();		query.append("UPDATE ").append(table);		System.err.println("fieldNames.length:" + fieldNames.length);		if (fieldNames.length > 0) {			query.append(" SET ");			query.append(fieldNames[1] + " = ?");			query.append("," + fieldNames[2] + " = ?");			query.append("," + fieldNames[3] + " = ?");			query.append("," + fieldNames[4] + " = ?");			query.append("," + fieldNames[5] + " = ?");			query.append("," + fieldNames[6] + " = ?");			query.append(" WHERE ");			query.append(fieldNames[0] + " = ?");			System.err.println(query.toString());			return query.toString();		} else {			return null;		}  }
Copy after login


按照java的思想我这里其实可以通过extends DBOutputFomat来实现update mysql的功能 ,但是我试了死活不行,暂且记下 有时间再来仔细揣摩

重载方式代码(测试未通过)有知道为什么的还请不吝赐教

import org.apache.hadoop.mapreduce.lib.db.DBOutputFormat;import org.apache.hadoop.mapreduce.lib.db.DBWritable;public class MysqlOutputFormat1<k extends dbwritable> extends DBOutputFormat<k v> {	public String constructQuery(String table, String[] fieldNames) {		if (fieldNames == null) {			throw new IllegalArgumentException(					"Field names may not be null");		}		StringBuilder query = new StringBuilder();		query.append("UPDATE ").append(table);		System.err.println("fieldNames.length:"+fieldNames.length);		if (fieldNames.length > 0) {			query.append(" SET ");			query.append(fieldNames[1] + " = ?");			query.append("," + fieldNames[2] + " = ?");			query.append("," + fieldNames[3] + " = ?");			query.append("," + fieldNames[4] + " = ?");			query.append("," + fieldNames[5] + " = ?");			query.append("," + fieldNames[6] + " = ?");			query.append(" WHERE ");			query.append(fieldNames[0] + " = ?");			System.err.println(query.toString());			return query.toString();		} else {			return null;		}	}}</k></k>
Copy after login


另外可以通过我感觉可以通过sql语句的merge方式生成merge语句从而实现有则更新 没有则插入 参考网页http://en.wikipedia.org/wiki/Merge_%28SQL%29

--http://en.wikipedia.org/wiki/Merge_%28SQL%29 MERGE INTO tablename USING table_reference ON (condition)   WHEN MATCHED THEN   UPDATE SET column1 = value1 [, column2 = value2 ...]   WHEN NOT MATCHED THEN   INSERT (column1 [, column2 ...]) VALUES (value1 [, value2 ...
Copy after login


 

 

source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!