Frequently Asked Questions Answers in the GUAVA (Google Common Libraares) Input/OUTPUT framework
Guava (Google Common Libraares) is a powerful Java class library that provides a wide and rich INPUT/OUTPUT framework.This article will answer some common questions about the Guava Input/Output framework and provide Java code examples.
Question 1: What is the Input/OUTPUT framework of Guava?
Guava's INPUT/OUTPUT framework is a module for processing input and output operations.It provides various tools and interfaces to simplify common input and output tasks.
Question 2: How to read the file with Guava?
You can use the GUAVA Files tool class to read the file.The following is a sample code that reads the content of the file with Guava:
import com.google.common.base.Charsets;
import com.google.common.io.Files;
import java.io.File;
import java.io.IOException;
import java.util.List;
public class FileReadExample {
public static void main(String[] args) {
File file = new File("path/to/file.txt");
try {
List<String> lines = Files.readLines(file, Charsets.UTF_8);
for (String line : lines) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
Question 3: How to use Guava to write files?
The Guava Files tool class can also be used for file writing.Below is a sample code that uses Guava to write file content:
import com.google.common.base.Charsets;
import com.google.common.io.Files;
import java.io.File;
import java.io.IOException;
import java.util.List;
public class FileWriteExample {
public static void main(String[] args) {
File file = new File("path/to/file.txt");
try {
List<String> lines = List.of("Line 1", "Line 2", "Line 3");
Files.write(lines, file, Charsets.UTF_8);
} catch (IOException e) {
e.printStackTrace();
}
}
}
Question 4: How to use Guava to process byte flow?
The GUAVA's Bytestreams tool class provides a method of processing byte running.The following is a sample code that uses GUAVA for byte reading and writing operations:
import com.google.common.io.ByteStreams;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class ByteStreamExample {
public static void main(String[] args) {
try {
FileInputStream input = new FileInputStream("path/to/input.txt");
FileOutputStream output = new FileOutputStream("path/to/output.txt");
ByteStreams.copy(input, output);
input.close();
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Question 5: How to use Guava to process character stream?
Guava's Charstreams tool class provides a method of processing character stream.Below is a sample code that uses Guava to perform character stream reading and writing operations:
import com.google.common.io.CharStreams;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class CharStreamExample {
public static void main(String[] args) {
try {
FileReader reader = new FileReader("path/to/input.txt");
FileWriter writer = new FileWriter("path/to/output.txt");
CharStreams.copy(reader, writer);
reader.close();
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Question 6: How to use Guava for line -based processing?
Guava's LineProcessor interface can be used for line -based processing.Below is a sample code based on GUAVA for row processing. This example calculates the sum of the number of rows in the file:
import com.google.common.base.Charsets;
import com.google.common.io.Files;
import com.google.common.io.LineProcessor;
import java.io.File;
import java.io.IOException;
public class LineProcessorExample {
public static void main(String[] args) {
File file = new File("path/to/file.txt");
try {
int totalLines = Files.asCharSource(file, Charsets.UTF_8).readLines(new LineCounter());
System.out.println("Total lines: " + totalLines);
} catch (IOException e) {
e.printStackTrace();
}
}
static class LineCounter implements LineProcessor<Integer> {
private int lineCount = 0;
@Override
public boolean processLine(String line) throws IOException {
lineCount++;
return true;
}
@Override
public Integer getResult() {
return lineCount;
}
}
}
The above are common questions and answers about the Guava Input/Output framework.I hope this article can help you better understand and use the Input/OUTPUT module of Guava.
