Guava: GOOGLE CORE LIBRARIES for Java performance optimization skills
Title: Guava: Google Core Libraries for Java Performance Optimization Skills
Introduction:
Guava is a set of open source Java core libraries released by Google.It provides a lot of practical tools and functions to help us write Java code more efficiently.In addition, Guava also provides some performance optimization techniques that make our applications perform better in terms of performance.This article will introduce some techniques for performance optimization using Guava and provide some Java code examples.
1. Avoid creating unnecessary objects
In Java, frequent creation of objects will cause frequent distribution of memory and garbage recycling, thereby reducing the performance of the application.Guava provides some tools to help us avoid creating unnecessary objects.For example, using Guava's `Optional` type can avoid returning` null` values, and tool classes such as `ints`,` Longs`, `Floats` and` DoubleS` can avoid creating basic data type packaging classes.
Example code:
Optional<String> optionalValue = Optional.of("Hello");
String value = optionalValue.or("Default value");
int intValue = Ints.tryParse("123");
System.out.println(intValue);
Second, use cache
The Guava's `Cache` class can help us realize the cache mechanism to improve the speed of data reading.By causing the read data in the memory, a disk or network IO operation can be performed every time you read the data to speed up the response speed of the application.
Example code:
LoadingCache<String, Object> cache = CacheBuilder.newBuilder()
.maximumSize(100)
.expireAfterWrite(10, TimeUnit.MINUTES)
.build(
new CacheLoader<String, Object>() {
public Object load(String key) throws Exception {
// Read the logic of data from the database or network
return fetchData(key);
}
});
Object value = cache.get("key");
3. Use the collection tool class
Guava provides some collection tool classes that can help us operate the collection more efficiently.For example, `lists.newarrayList ()` method can be used to create a variable arrayList, while the `ImmutableList` class can create an unable variable list.These collection tool classes are optimized in terms of performance, which can improve code execution efficiency.
Example code:
List<Integer> list = Lists.newArrayList(1, 2, 3, 4, 5);
System.out.println(list);
List<Integer> immutableList = ImmutableList.of(1, 2, 3, 4, 5);
System.out.println(immutableList);
4. Use functional programming style
GUAVA's functional programming style can help us write more concise, readable code, and have improved performance in terms of performance.For example, the `Predicates` class provided by Guava can be used to create conditional judgment functions. The Functions" class can be used to create a conversion function. These functions can greatly simplify the writing of the code in the collection operation and improve the execution efficiency.
Example code:
List<Integer> numbers = Lists.newArrayList(1, 2, 3, 4, 5);
List<Integer> evenNumbers = Lists.newArrayList(Collections2.filter(numbers, Predicates.compose(Predicates.equal(0), Functions.mod(2))));
System.out.println(evenNumbers);
in conclusion:
This article introduces some techniques for performance optimization using Guava, and demonstrates the relevant Java code examples.By avoiding creating unnecessary objects, using cache, using collection tool classes and functional programming styles, we can improve the performance of the application and improve the readability of the code.I hope these techniques can help readers better use Guava for Java development.
