Java Program for MapReduce processing data

1, through the traditional Key-value class analysis data

When you create a key class, all keys inherit the Writablecomparable interface

public class Sendorkey implements Writablecomparable

{

Default Constructor+parameterized constructor

Implementation of ReadFields method

Implementation of Write method

Overriding the Compare to method

}

Sensorkey.java

Sensorvalue.java

"Note: The default constructor initializes the variable

Constructors with parameters initialize class variables with their parameter values

The default ReadFields method parameter is datainput, regardless of what the content is, we use the Readfield method to accept and pass the data entered into this class, regardless of the dataoutput content, the Write method will output the data

In the Compreto method logic, we will compare the different sensors

Each property contains a get and set method "

2, creating a customized Recordreader class (how to create a custom Recordreader Class)

"Note: The custom Recordreader will inherit the default Recordreader, his parameters when the custom Key,value type, in Nextkeyvalue, we get the current value from the reader that contains the full record. Records, the columns are split according to the TDB key, and the first three columns are assigned to the key class, and the value class is assigned a value of "

3.creating a customized InputFormat class

Java Program for MapReduce processing data