Hadoop MapRduce 重写DBOutputFormat更新mysql数据库_MySQL

 

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);	}}

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>

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>

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;		}  }

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>

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 ...