The best practice and optimization technique of the Core framework in the Java class library
The best practice and optimization technique of the Core framework in the Java class library
Introduction:
The Core framework in the Java class library is an indispensable part of developing Java applications.It contains the core category and interfaces of the Java language and provides many important functions and characteristics.During the development process, understanding the best practice and optimization skills of the Core framework can help developers better use and improve the performance of the application.
Best practice and optimization skills:
1. Using non -changing classes: Unchanged classes refer to classes that cannot be changed after the creation.Using non -conversion category can improve the security and reliability of the code, and does not need additional synchronization operations in the multi -threaded environment.For example, you can use the `java.lang.string` class to store string because it is immutable.
Example code:
String str = "Hello";
str = str + "world"; // Created a new string object
2. Avoid using magic numbers: Magic numbers refer to unpretional numbers that appear directly in the code.Use constant or enumeration types to replace magic numbers to improve the readability and maintenance of code.Definition constants help uniformly manage and modify the same value.
Example code:
final int MAX_SIZE = 10;
for (int i = 0; i < MAX_SIZE; i++) {
// Circle execution code
}
3. Use the TRY-WITH-Resources statement to handle resources: In Java 7 and above, you can use the Try-With-Resources statement to close the resource of the interface of `java.lang.Autoclose".This can avoid the problem of memory leakage caused by forgetting to close resources.
Example code:
try (FileInputStream fileInputStream = new FileInputStream("file.txt")) {
// Use the file input flow reading data
} catch (IOException e) {
e.printStackTrace();
}
4. Use StringBuilder or StringBuffer for string stitching: When processing a large number of string stitching, using StringBuilder or StringBuffer can improve performance.StringBuilder is non -threaded and suitable for a single -threaded environment; StringBuffer is thread -safe and suitable for multi -threaded environment.
Example code:
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("Hello");
stringBuilder.append(" World");
String result = stringBuilder.toString();
5. Use the Java collection framework: The Java collection framework provides a set of interfaces and classes for storage, operation and access data.Select the appropriate collection class according to specific needs, such as List, SET, MAP, etc., which can improve the readability and performance of the code.
Example code:
List<String> list = new ArrayList<>();
list.add("Java");
list.add("Python");
list.add("C++");
for (String element : list) {
System.out.println(element);
}
6. Understand and use the appropriate thread pool: In the multi -threaded environment, the use of thread pools can be reused to use the created threads to reduce the creation and destruction of threads.You can use the method provided by `java.util.concurrent.executors` to create a thread pool.
Example code:
ExecutorService executorService = Executors.newFixedThreadPool(5);
executorService.execute(() -> {
// Code executing task
});
executorService.shutdown();
Summarize:
This article introduces the best practice and optimization technique of using the Core framework in the Java library.Through reasonable use of unavailable categories, avoiding magic figures, using Try-With-Resources statement, using StringBuilder or StringBuffer for string stitching, using the Java set framework, and understanding and using appropriate thread pools can improve the readability of the code,Maintenance and performance.I hope these practices and skills will help Java developers.
