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Azhwani 2023-06-08 21:43:31 +02:00 committed by GitHub
parent 9918d614e6
commit 5bfb63b2a1
1 changed files with 62 additions and 0 deletions

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@ -1,9 +1,16 @@
package com.baeldung.readlargefile; package com.baeldung.readlargefile;
import java.io.BufferedReader;
import java.io.File; import java.io.File;
import java.io.FileInputStream; import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException; import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SeekableByteChannel;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.Scanner; import java.util.Scanner;
import java.util.stream.Stream;
import org.apache.commons.io.FileUtils; import org.apache.commons.io.FileUtils;
import org.apache.commons.io.LineIterator; import org.apache.commons.io.LineIterator;
@ -93,6 +100,61 @@ public class ReadLargeFileUnitTest {
logMemory(); logMemory();
} }
@Test
public void givenUsingBufferedReader_whenIteratingAFile_thenCorrect() throws IOException {
String fileName = "src/test/resources/myFile";
logMemory();
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
while (br.readLine() != null) {
// do something with each line
}
}
logMemory();
}
@Test
public void givenUsingNewBufferedReader_whenIteratingAFile_thenCorrect() throws IOException {
String fileName = "src/test/resources/myFile";
logMemory();
try (BufferedReader br = java.nio.file.Files.newBufferedReader(Paths.get(fileName))) {
while (br.readLine() != null) {
// do something with each line
}
}
logMemory();
}
@Test
public void givenUsingSeekableByteChannel_whenIteratingAFile_thenCorrect() throws IOException {
String fileName = "src/test/resources/myFile";
logMemory();
try (SeekableByteChannel ch = java.nio.file.Files.newByteChannel(Paths.get(fileName), StandardOpenOption.READ)) {
ByteBuffer bf = ByteBuffer.allocate(1000);
while (ch.read(bf) > 0) {
bf.flip();
// System.out.println(new String(bf.array()));
bf.clear();
}
}
logMemory();
}
@Test
public void givenUsingStreamApi_whenIteratingAFile_thenCorrect() throws IOException {
String fileName = "src/test/resources/myFile";
logMemory();
try (Stream<String> lines = java.nio.file.Files.lines(Paths.get(fileName))) {
lines.forEach(line -> {
// do something with each line
});
}
logMemory();
}
// utils // utils
private final void logMemory() { private final void logMemory() {