Java8 program to read data from file and displaying Statistics of data

 
Employees date of birth is stored in an file in the following format:

08/06/1984

29/5/1982

20/1/1989

17/5/1989

22nd October 1991

14th December 1991

20th February 1994

27th July 1990

26th Dec 1991

12th Nov 1990

19th Dec 1990

27th Dec 1989

Java8 IntSummaryStatistics class to calculate total employees, total age, and average age group of the organization.  

 import java.nio.file.Files;  
 import java.nio.file.Paths;  
 import java.time.LocalDate;  
 import java.util.IntSummaryStatistics;  
 import java.util.stream.Stream;  
 public class DemoExample {  
      public static void main(String... args) {  
           try (Stream<String> lines = Files.lines(Paths.get("demo"))) {  
                IntSummaryStatistics intstream = lines.sequential()  
                          .mapToInt(e -> LocalDate.now().getYear() - Integer.parseInt(e.substring(e.trim().length() - 4)))  
                          .summaryStatistics();  
                long total_age = intstream.getSum();  
                long total_count = intstream.getCount();  
                double avg_age = intstream.getAverage();  
                System.out.println("Total employees :" + total_count);  
                System.out.println("Total age is :" + total_age);  
                System.out.println("Average age is :" + avg_age);  
           } catch (Exception e) {  
                e.printStackTrace();  
           }  
      }  
 }  

Java with Apache POI

Apache POI to create excel file

---

Maven dependencies:


<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.9</version>
</dependency>

<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.9</version>
</dependency>

Example:

---

 import java.io.File;  
 import java.io.FileOutputStream;  
 import java.io.IOException;  
 import java.nio.file.Files;  
 import java.nio.file.Paths;  
 import org.apache.poi.ss.usermodel.Cell;  
 import org.apache.poi.ss.usermodel.Row;  
 import org.apache.poi.ss.usermodel.Sheet;  
 import org.apache.poi.ss.usermodel.Workbook;  
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;  
 public class WorkingWithExcel {  
      public static void main(String[] args) {  
           createWorkBook();  
      }  
      /**  
       * Create workbook with one work sheet. Once work sheet is created, then  
       * content will be added to the work sheet.  
       */  
      private static void createWorkBook() {  
           final String WORKBOOK_NAME = "emp_workbook.xlsx";  
           if (!Files.exists(Paths.get(WORKBOOK_NAME))) {  
                try (FileOutputStream fos = new FileOutputStream(new File("emp_workbook.xlsx"))) {  
                     Workbook workbook = new XSSFWorkbook();  
                     Sheet sheet = workbook.createSheet("emp_details");  
                     int rowcount = 0;  
                     Row row = sheet.createRow(rowcount++);  
                     Object[] colHeading = getColumnHeadings();  
                     int i = 0;  
                     for (Object obj : colHeading) {  
                          Cell cell = row.createCell(i++);  
                          cell.setCellValue((String) obj);  
                     }  
                     Object empData[][] = getEmpData();  
                     for (Object obj[] : empData) {  
                          i = 0;  
                          row = sheet.createRow(rowcount++);  
                          for (Object ob : obj) {  
                               Cell cell = row.createCell(i++);  
                               cell.setCellValue((String) ob);  
                          }  
                     }  
                     workbook.write(fos);  
                     System.out.println("Work book is created successfully with name :" + WORKBOOK_NAME);  
                } catch (IOException e) {  
                     e.printStackTrace();  
                }  
           } else {  
                System.out.println("File already exists with the name :" + WORKBOOK_NAME);  
           }  
      }  
      /**  
       * To return work sheet headings  
       *   
       * @return  
       */  
      private static Object[] getColumnHeadings() {  
           return new Object[] { "EMPNO", "ENAME", "EMAIL", "CITY" };  
      }  
      /**  
       * Actual data to add to work sheet  
       *   
       * @return  
       */  
      public static Object[][] getEmpData() {  
           return new Object[][] { { "SPAN001", "Lakshman", "lakshman.a@spaneos.com", "Bangalore" },  
                     { "SPAN002", "Krish", "krish.t@spaneos.com", "Bangalore" },  
                     { "SPAN003", "Suresh", "suresh.s@spaneos.com", "Bangalore" },  
                     { "SPAN004", "Ramesh", "ramesh.r@spaneos.com", "Bangalore" } };  
      }  
 }