I have made a little javaFX app that reads from the database and writes to a file using openCSV.Everything is fine now.In the file i have a column and its values contain the path of an image(Example : /home/user/folder1/image.jpg).What i have to do is replace all the values of this column ,with another value that contains only the last folder name and the image name(Example : folder1/image.jpg).I read about this and i realised that i had to write a lot of code.What i am asking is if there is another way of doing this? For example can i replace all of this values directly from the query or can i use another library that lets me write to a specific column?
Thanks :)
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Using Java Processing I'm trying to find the last time that a specific string value is found in a table column and get another value from the cell next to it.
How would I do something like this?
Use any of the several available CSV parsing tools to read your file. For example, Apache Commons CSV.
As you read in each line, test if it contains your target value. If so, remember that row by stashing in a variable. Each time you find a hit, replace the previously stashed value with the latest, storing in that same variable.
When done reading the file, the last row meeting your criteria is in that variable. Now read the adjacent cell from that row. Voilà, your result.
You will find many examples of reading CSV files in existing Questions and Answers. Again, I recommend you use a library for reading and parsing the CSV rather than perform that chore yourself.
I am facing a problem in writing in MS Word file using Docx4j. The scenario is something like:
First user writes into the word file and supposedly he takes about 10 rows of the table and saves the file.
Second user comes and writes about 5 rows and saves the file again. But after sometime he again opens the file and modify something through java application.
Modified text is being added into the file instead of replacing the old text.
Now I want to replace his old text and want to save new paragraphs in table.
In simple words I want to replace old table rows with new one in Docx4j.
How can I reach to my desired rows to replace them?
Can anybody help me in this? Thanks
Use Replace to what you try do is just replace the String
Check this
https://www.docx4java.org/forums/docx-java-f6/replace-text-into-docx-within-a-table-t6.html
I have two csv files employee.csv and loan.csv.
In employee.csv I have four columns i.e. empid(Integer),name(String),age(Integer),education(String).
In loan.csv I have three columns i.e. loan(Double),balance(Double),empid(Integer).
Now, I want to merge these two csv files into a single csv file by empid column.So in the result.csv file the columns should be,
empid(Integer),
name(String),
age(Integer),
education(String),
loan(Double),
balance(Double).
Also I have to achieve this only by using kettle api program in Java.
Can anyone please help me?
First of all, you need to create a kettle transformation as below:
Take two "CSV Input Step", one for employee.csv and another for loan.csv
Hop the input to the "Stream Lookup" step and lookup using the "emplid"
Final step : Take a Text file output to generate a csv file output.
I have placed the ktr code in here.
Secondly, if you want to execute this transformation using Java, i suggest you read this blog. I have explained how to execute a .ktr/.kjb file using Java.
Extra points:
If its required that the names of the csv files need to be passed as a parameter from the Java code, you can do that by adding the below code:
trans.setParameterValue(parameterName, parameterValue);
where parameterName is the some variable name
and parameterValue is the name of the file or the location.
I have already taken the files names as the parameter in the kettle code i have shared.
Hope it helps :)
I have to read a text file and write it to an already existing excel file. The excel file is a customized excel sheet with different items in different columns. The items has different values for each of them... These items with there value can be found in a text file. But i dont have much idea as to how to do this.
E.g- example.txt
Name: John
Age=24
Sex=M
Graduate=M.S
example.xlsx
Age: Sex:
Name: Graduate:
Thanks in advance :)
Just as for so many other problems that need solved, there's an Apache library for that! In this case, it's the POI library. I've only used it for very basic spreadsheet manipulation, but managed that by just following a few tutorials. I'd link to one, but I can't now remember where it was.
Please see Apache POI-HSSF library for reading and writing Excel files with Java. There are some quick guides to get you started.
This post How to read and write excel file in java might help you.
You can also create a *.csv (comma separated value) file in Java. Just create a simple text file with CSV extension and put your values in there like that :
Age:,24,Sex:,M,
So you just separate your values with commas (or other delimiters like ';').
Every line in this file is a row, and every delimiter separates two columns. You won't be able to add colours/styles/formatting this way, but it gives you a file that is openable and understandable even without Excel (or other spreadsheet software).
I want to make a GUI application that contains three functions as follows:
Add a record
Edit a record
Delete a record
A record contains two fields - Name and Profession
There are two restrictions for the application
You can't use database to store info. You have to use a flat file.
Total file should not be re-written for every add/delete operation.
So, my questions are mentioned below:
Q1. Which file format would be better? (.xml or .csv or .txt or any other)
Q2. How can we perform the add/delete operation without the whole file being re-written?
The second part of your question is answered here : Best Way to Write Bytes in the Middle of a File in Java
As for the format - I would go with something as simple as possible. You don't want to have to deal with a bunch of markup processing, as using RandomAccessFile, you will going directly to a byte position. A fixed width style format would be good, so that based on the record number, you can calculate the starting position of a record or field in the file, without having to read everything in the file. The fields would then be padded out to the fixed width with spaces or some other suitable character.
I would go with CSV, zipped. it is both readable, and editable externally.
If CSV is your choice, this can help: http://javacsv.sourceforge.net/
Did you look at this? http://sourceforge.net/projects/flatworm/
Also consider Apache Derbi and HSQLDB
Another solution is this http://www.coyotegulch.com/products/jisp/index.html
You can reinvent the wheel, but that is only required if this is an academic assigment...
Given that the whole file must not be rewritten, I would suggest using RandomAccessFile that allow you to read and write only the record you want.
For the file format, a binary file, using fixed length for the record : ex: Name on 20 characters, Profession on 30.
This will allow you to use the seek() method of RandomAccessFile to directly access your data.