Guava: GOOGLE CORE LIBRARIES for Java detailed documentation
Guava: GOOGLE CORE LIBRARIES for Java detailed documentation
Overview:
Guava is a set of core libraries provided by Google for Java developers to simplify common tasks in the development of Java.It provides many practical tool classes and functions, covering various fields, from setting operation to concurrent programming, and string processing to I/O operations.In this document, we will introduce some of the key features in the Guava library and provide the corresponding Java code example.
1. Collection operation:
The GUAVA collection operation function can greatly simplify the common operations of the Java collection.It provides some practical tool categories and methods, such as filtering, mapping, mergers, etc., as well as the sorting and traversal operation of the collection.
Example code:
// Import the required GUAVA class
import com.google.common.collect.Lists;
// Create a list
List<Integer> numbers = Lists.newArrayList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
// Use Guava to filter out the even number
List<Integer> evenNumbers = Lists.newArrayList(Collections2.filter(numbers, new Predicate<Integer>() {
@Override
public boolean apply(Integer number) {
return number % 2 == 0;
}
}));
// Print the result after filtering
for (Integer number : evenNumbers) {
System.out.println(number);
}
2. Concurrent programming:
GUAVA's concurrent programming function provides some practical categories and methods, simplifying the task of concurrent programming in multi -threaded environments.It provides functions such as thread pools, complications, and atomic operations.
Example code:
// Import the required GUAVA class
import com.google.common.util.concurrent.*;
// Create a thread pool
ListeningExecutorService executorService = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
// Submit asynchronous tasks
ListenableFuture<Integer> future = executorService.submit(() -> {
// Perform some time -consuming tasks
return calculateResult();
});
// Add callback method
Futures.addCallback(future, new FutureCallback<Integer>() {
@Override
public void onSuccess(Integer result) {
// Processing successful return results
System.out.println("Calculation result: " + result);
}
@Override
public void onFailure(Throwable t) {
// Treatment abnormal situation
System.out.println("Calculation failed: " + t.getMessage());
}
}, executorService);
3. String processing:
Guava provides some convenient methods to handle string, including splitting, connection, replacement, conversion and other functions.It also provides support for string encoding.
Example code:
// Import the required GUAVA class
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.CharMatcher;
import com.google.common.base.Charsets;
import com.google.common.io.BaseEncoding;
// Use the Joiner connection string
String joinedString = Joiner.on(", ").skipNulls().join("Hello", null, "World");
// The result of the output connection
System.out.println(joinedString);
// Use Splitter to split string
Iterable<String> splitString = Splitter.on(", ").trimResults().omitEmptyStrings().split(joinedString);
// The result of the disassembly after the split
for (String str : splitString) {
System.out.println(str);
}
// Use Charmatcher to remove special characters in the string
String cleanString = CharMatcher.is('a').removeFrom("abracadabra");
// The result of the output after removing special characters
System.out.println(cleanString);
// Use Charsets to obtain a specific character set encoding
Charset charset = Charsets.UTF_8;
// Use Baseencoding for encoding and decoding
BaseEncoding base64Encoding = BaseEncoding.base64();
String encodedString = base64Encoding.encode("Hello, World".getBytes(charset));
byte[] decodedBytes = base64Encoding.decode(encodedString);
// The result of the output encoding and decoding
System.out.println(encodedString);
System.out.println(new String(decodedBytes, charset));
Summarize:
This article provides a detailed document of the Guava library, which introduces its characteristics of collective operations, concurrent programming, and string processing.By providing code examples, readers can better understand how to use the Guava library to simplify common tasks in the development of Java.
