Write a data into Excel file in java.

Writing the data into java is having few easy steps.

Step 1- Create HSSFWorkbook class object.
HSSFWorkbook workbook = new HSSFWorkbook();

Step 2- Call workbook.createSheet() method by mentioning the sheet name.
HSSFSheet sheet = workbook.createSheet("Sample sheet");

Read Data from Excel file in java.

We cas read or write the data in Excel using apache poi apis. In below example I'm going to use "poi-3.12-20150511.jar".

Step 1- Create Excel file with some data.

Year    Country    By
1975    West Indies    17 run
1979    West Indies    92 run
1983    India    43 run
1987    Australia    7 run
1992    Pakistan    22 run
1996    Sri Lanka    7 wicket
1999    Australia    8 wicket
2003    Australia    125 run
2007    Australia    53 run
2001    India    6 wicket
2015    Australia    7 wicket

Step 2- Create
String fileName = "D:\\Ashish\\Personal\\WebApplication1\\iccworlcuplist.xls";
FileInputStream file = new FileInputStream(new File(fileName));

Read the data from CSV file and Map it to java object in java.

If you want to read the CSV file and store the data into java object no need to set the data into java object one by one. Opencsv has given a nice feature for this.

Step 1- Create CSV file."worldcup.csv"

1975,WestInddies,Australia,17 Run
1979,WestInddies,England,92 Run
1983,India,WestInddies,43 Run
1987,Australia,England,7 Run
1992,Pakistan,England,22 Run
1996,Sri Lanka,Australia,7 Wicket
1999,Australia,Pakistan,8 Wicket
2003,Australia,India,125 Run
2007,Australia,Sri Lanka,53 Run
2011,India,Sri Lanka,6 Wicket
2015,Australia,New Zeland,7 Wicket

Write Data into csv file in java.

To reading the data from csv file either use java IO library or usr third pary jar like "opencsv.jar". In given example I'm using opencsv.jar.

Step 1-  Create CSVWriter object.
String csv = "D:\\Ashish\\Personal\\WebApplication1\\worldcupwrite2.csv";
CSVWriter writer = new CSVWriter(new FileWriter(csv));

Step 2- Create String array for data
String[] country = "WestInddies#India#Australia#Pakistan#Sri Lanka".split("#");

Step 3- Call writer.writeNext(country) method and pass the String array object as data.

Read Data at a time from csv file in java.

To reading the data from csv file either use java IO library or usr third pary jar like "opencsv.jar". In given example I'm using opencsv.jar.

Step 1- Create csv file."worldcup.csv"

1975,WestInddies,Australia,17 Run
1979,WestInddies,England,92 Run
1983,India,WestInddies,43 Run
1987,Australia,England,7 Run
1992,Pakistan,England,22 Run
1996,Sri Lanka,Australia,7 Wicket
1999,Australia,Pakistan,8 Wicket
2003,Australia,India,125 Run
2007,Australia,Sri Lanka,53 Run
2011,India,Sri Lanka,6 Wicket
2015,Australia,New Zeland,7 Wicket

Read Data from csv file line by line in java.

To reading the data from csv file either use java IO library or usr third pary jar like "opencsv.jar". In given example I'm using opencsv.jar.

Step 1- Create csv file. "worldcup.csv"

1975,WestInddies,Australia,17 Run
1979,WestInddies,England,92 Run
1983,India,WestInddies,43 Run
1987,Australia,England,7 Run
1992,Pakistan,England,22 Run
1996,Sri Lanka,Australia,7 Wicket
1999,Australia,Pakistan,8 Wicket
2003,Australia,India,125 Run
2007,Australia,Sri Lanka,53 Run
2011,India,Sri Lanka,6 Wicket
2015,Australia,New Zeland,7 Wicket

Pagination in java jsp.

The pagination is very useful when we have large number of records in a table. If we displaying all the record the at a time it will take more time to load all the data and taking more memory. So it's not a good for either memory or performance point of view. If we go for pagination it will load limited amount of record at a time so it will good for both memory and performance point of view.

In this example i'm going to display one of db table record in tabular format using pagination. I'm loading only 5 record at a time. Each request fetching  only 5 Record at a time by using below variable-
showRows = 5 (display the number of record per page)
totalRecords = 5 display the number of page at a time like 1,2,3,4,5 hyper link will come on each time