org.apache.hadoop.mapreduce.lib.db

类 DataDrivenDBRecordReader<T extends DBWritable>

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<LongWritable,T>

org.apache.hadoop.mapreduce.lib.db.DBRecordReader<T>

org.apache.hadoop.mapreduce.lib.db.DataDrivenDBRecordReader<T>

所有已实现的接口:

Closeable, AutoCloseable

直接已知子类:

MySQLDataDrivenDBRecordReader, OracleDataDrivenDBRecordReader

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class DataDrivenDBRecordReader<T extends DBWritable>
extends DBRecordReader<T>

A RecordReader that reads records from a SQL table, using data-driven WHERE clause splits. Emits LongWritables containing the record number as key and DBWritables as value.

字段概要

从类继承的字段 org.apache.hadoop.mapreduce.lib.db.DBRecordReader

statement

构造器概要

构造器

构造器和说明
DataDrivenDBRecordReader(DBInputFormat.DBInputSplit split, Class<T> inputClass, Configuration conf, Connection conn, DBConfiguration dbConfig, String cond, String[] fields, String table, String dbProduct)

方法概要

方法

限定符和类型	方法和说明
protected String	getSelectQuery() Returns the query for selecting the records, subclasses can override this for custom behaviour.

从类继承的方法 org.apache.hadoop.mapreduce.lib.db.DBRecordReader

close, createValue, executeQuery, getConditions, getConnection, getCurrentKey, getCurrentValue, getDBConf, getFieldNames, getPos, getProgress, getSplit, getStatement, getTableName, initialize, next, nextKeyValue, setStatement

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

DataDrivenDBRecordReader

public DataDrivenDBRecordReader(DBInputFormat.DBInputSplit split,
                        Class<T> inputClass,
                        Configuration conf,
                        Connection conn,
                        DBConfiguration dbConfig,
                        String cond,
                        String[] fields,
                        String table,
                        String dbProduct)
                         throws SQLException

参数:

split - The InputSplit to read data for

抛出:

SQLException

方法详细资料

getSelectQuery

protected String getSelectQuery()

Returns the query for selecting the records, subclasses can override this for custom behaviour.

覆盖:

getSelectQuery 在类中 DBRecordReader<T extends DBWritable>