Introduction
This program helps to read any specific Text or Contents from the file or multiple files from the folder location.
This program can be used when we want to search any specific records like –
- There are specific Exception need to search and pick some line like 3 0r 5
- There are specific IDs which user wants to search from the 100 files for document purpose.
Please find a program written in Java and let us know if any issue.
Note: We have written this Program using Simple way because everyone can understand and utilize. There are many other and optimized way to develop this program.
Program in Java
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
/**
* This class helps to read data/records from set of files.
*
* @author dsahu1
*
*/
public class KWReadContentsFromFiles {
/**
* This method helps to execute the program.
*
* @param args
*/
public static void main(String[] args) {
// Call method to start business logic to retrieve information
readContentsFromFilesByText(
"C:/Logs/Exception_20171104/",
"Exception", ".txt", 3);
}
/**
* This method helps to read data from Files based on passed text.
*
* @param filesPath
* @param textToSearch
* @param fileType
*/
private static void readContentsFromFilesByText(String filesPath,
String textToSearch, final String fileType, int numberOfLinePrint) {
// Instantiate FilenameFilter filter
FilenameFilter filter = new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(fileType);
}
};
File folder = new File(filesPath);
// Retrieve list of Files available
File[] listOfFiles = folder.listFiles(filter);
StringBuilder filteredOutput = new StringBuilder();
// Iterate all Files one by one to Read Text Information
for (int i = 0; i < listOfFiles.length; i++) {
File file = listOfFiles[i];
String line = null;
String fileName = file.getName();
// Initiate count to capture number of line in the output
int count = 0;
try {
// FileReader reads text files in the default encoding.
FileReader fileReader = new FileReader(file);
// Always wrap FileReader in BufferedReader.
BufferedReader bufferedReader = new BufferedReader(fileReader);
// Boolean variable to hold contents availability
boolean isContaintFound = false;
// Read Files
while ((line = bufferedReader.readLine()) != null) {
// Check passed text to search
if (line.contains(textToSearch)) {
isContaintFound = true;
filteredOutput.append(line).append("\n");
count++;
continue;
} else if (isContaintFound && count < numberOfLinePrint) {
count++;
filteredOutput.append(line).append("\n");
} else if (isContaintFound && count == numberOfLinePrint) {
filteredOutput.append(line).append("\n");
isContaintFound = false;
}
}
if (count != 0) {
filteredOutput.append("****File Name **** ")
.append(fileName)
.append(" Total Occurence :" + count).append("\n");
count = 0;
}
bufferedReader.close();
} catch (FileNotFoundException ex) {
System.out.println("Unable to open file '" + fileName + "'");
} catch (IOException ex) {
System.out.println("Error reading file '" + fileName + "'");
}
}
}
}