Multithread java class

Here is a sample class to run multiple thread in a class. All threads are started in a for loop and after all threads are finished thread join function will wait for all thread to finish.

public class MultiThreadRules {

class MultiThreads implements Runnable {
   private String rulePath;
   public MultiThreads(String rulePath){
                this.rulePath = rulePath;



for(int i=0; i<=5, i++){ //number of threads
this.inputValue = inputValue;
Thread t = new Thread(this);
t.start(); //all threads started
threads.add(t);  
}

try {
for(Thread tt:threads){
tt.join(); //all threads are done
}

} catch (InterruptedException e) {
logger.error(e.getMessage());
}




     }
     public void run() {
      //perform action here
     }
  }


}

Create excel file report with multiple sheets using poi

Previously have done a program to generate and populate excel file on multiple sheets. Firstly download the poi framework jar files from their website http://poi.apache.org/.
Then using array of strings, populate the array according to where the location the cell is. Example below, first array is the row and second array is the column.

String[][] excelData = new String[2000][50];

excelData[0][0] = "Title";
excelData[0][1] = "Name";
excelData[0][2] = "Code";
excelData[0][3] = "Description";


excelData[1][0] = "title 1";
excelData[1][1] = "mike";
excelData[1][2] = "code 1";
excelData[1][3] = "Description 1";


Depending on the number of sheets to generate in the excel file, add the array of strings into an arraylist.

Then pass the list of string of array to the method below together with the file name of excel to generate.
The sheet name to generate is declared in variable sheetName.


private static void writeDataToExcelFile(String fileName,
List<String[][]> resList) {
HSSFWorkbook myWorkBook = new HSSFWorkbook();
String sheetName = "";
for (int i = 0; i < resList.size(); i++) {
sheetName = "Document-" + i;
HSSFSheet mySheet = myWorkBook.createSheet(sheetName);
HSSFRow myRow = null;
HSSFCell myCell = null;
String[][] excelData = resList.get(i);
for (int rowNum = 0; rowNum < excelData.length; rowNum++) {
myRow = mySheet.createRow(rowNum);
for (int cellNum = 0; cellNum < excelData[0].length; cellNum++) {
myCell = myRow.createCell(cellNum);
myCell.setCellValue(excelData[rowNum][cellNum]);
}
}
}


try {
FileOutputStream out = new FileOutputStream(fileName + ".xls");
myWorkBook.write(out);
out.close();
} catch (Exception e) {
e.printStackTrace();
}


myWorkBook = null;

}

Reading properties file in java

Reading properties file is straightforward using ResourceBundle java util. Below are the codes. ResourceBundle will get the information from the setting-config.properties file. Make sure the properties file is  in the same path as the java class. The data obtained is passed into a map for easy retrieval using key value later.

private HashMap<String, String> propertiesMap = new HashMap<String, String>();

private ResourceBundle resourceBundle = null;


protected void readProperties() {
List<String> propList = new ArrayList<String>();
try {
resourceBundle = ResourceBundle.getBundle("setting-config");
for (Iterator<String> iterator = resourceBundle.keySet().iterator(); iterator.hasNext();) {
String keyString = iterator.next();
propertiesMap.put(keyString, resourceBundle.getString(keyString));
}
}catch (Exception exception) {
System.out.print(exception.getLocalizedMessage());
}
}