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Create hashmap and dynamically populate

 
Greenhorn
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Is it possible to create an hashmap and dynamically populate it ?

How can I do that?

Eg:

I want a hash map created with Keys " A, B , C" with null values ( A B C represent column names of a table)


The values for these keys come from a String parsed by split ( No of strings to be parsed runs into millions) Eg: 123|S|122.14, or S,344,122.146
Strings will be have values for keys (columns) A B C in different positions ( Eg: for 123|S|122.14 - Keys are A B C and for S,123,122.14 kEYS ARE B A C)


I want to bulk load db after maping them to hashmap lists(?) Basically get A=123 B=S C=122.14 using 123|S|122.14 and A=344 B= S and C=122.146 for S,344,122.146 and bulk load fast into a db table


Any ideas

Thanks
 
Bartender
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Abagesh Kumar wrote:Is it possible to create an hashmap and dynamically populate it ?


Yes.

Abagesh Kumar wrote:How can I do that?


You can write a code which puts key-value pairs in HashMap. I didn't get this question clearly.

Abagesh Kumar wrote:I want a hash map created with Keys " A, B , C" with null values


If values are null anyway, why do you need a Map? It can be done by List as well.

Abagesh Kumar wrote:
The values for these keys come from a String parsed by split ( No of strings to be parsed runs into millions) Eg: 123|S|122.14, or S,344,122.146
Strings will be have values for keys (columns) A B C in different positions ( Eg: for 123|S|122.14 - Keys are A B C and for S,123,122.14 kEYS ARE B A C)


Again, can you please clarify a more? I did not get what this is.

Abagesh Kumar wrote:I want to bulk load db after maping them to hashmap lists


What is 'bulk load db after mapping'? Which mapping? What is 'HashMap Lists'?

Can you please provide more clarification about what exactly are you trying to do? How? And where does HashMap comes into picture?
 
Abagesh Kumar
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I have 4 types of strings which have different delimiters(|, space, <> , comma)

I want to prase them with split . So I will have the substrings in an array

I want to have key=value pairs ( key is column name of table , values are substrings in the strings) ( hashmap comes into picture here) Since keys are same for all the strings( they are not part of the string, I have to map a key to the values which come from the string)

Finally, I want to load these into a db table.
=====================================================
Example:( Str1, Str2)

123|S|122.14,
S,344,122.146

We can define formats

A|B|C

B|A|C in the program

I want to store the A=123 B=S C=122.14
A=344 B=S C=122.146 ( hashmap)

( mapping the format string with actual value string) and finally load into db

This is the idea I have thought off. But I dont know how to write code for this. Hope I am clearer now.


Please advise Many thanks
 
Abagesh Kumar
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I created a hashmap which will have the keys A , B and C and have position no of substring before the actual string is parsed .

A=2 B= 1 and C=0. Then i am replacing with correct values

But I am getting this exception

A= 2834.56150 B= 1 C 0609
Exception in thread "main" java.lang.NumberFormatException: For input string: "2834.56150"

Please help.

----------------------------------------------------------------------------------



[Added code tags - see UseCodeTags for details]
 
Bartender
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Abagesh Kumar wrote:
But I am getting this exception

A= 2834.56150 B= 1 C 0609
Exception in thread "main" java.lang.NumberFormatException: For input string: "2834.56150"


You're using Integer.parse(). But 2834.56150 isn't an integer, is it?
 
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Find Java Hashmap list of hashmap faq with example. You will find solutions for  following most asked questions as below
- Ways To Iterate Hashmap.
- Difference Between Hashtable And Hashmap
- what Hashmap Return If Mapping Key Does Not Exist

and more. Visit QuizCure for more tech related queries.
 
Marshal
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