Introduction to the API framework in the Java class library

Introduction to the API framework in the Java class library In Java programming, the processing unit is a common task.In order to help developers handle the conversion and calculations of the measurement unit more easily, the Java class library provides a measured unit API framework.This framework provides a set of categories and interfaces to represent and operate various measurement units. The core concept of the API framework of the unit is Measurement and Unit.Measurement is an object that represents a specific measurement value, such as length, weight, time, etc.Unit is used to represent the object of the unit, such as rice, kg, second, etc. The calculation and conversion of the API framework of the measurement unit are very simple.First, we need to create a Measurement object to specify its value and unit.For example, to indicate a Measurement with a length of 5 meters, you can use the following code: Measurement<Length> lengthMeasurement = Measurement.of(5, Units.METRE); In this example, we use Units.metre provided by the UNITS class.Next, we can perform various computing operations on the Measurement object, such as addition, subtraction, multiplication, and division.For example, we can measure the two lengths and get a new Measurement object, indicating that its total length: Measurement<Length> lengthSum = lengthMeasurement.plus(Measurement.of(3, Units.METRE)); In addition to the basic calculation operation, the API framework of the unit also provides a variety of convenient conversion methods.For example, we can convert a length unit into another.The following code converts a MEASUREMENT object with a length of 5 meters into Measurement objects in a feet: a feet: Measurement<Length> feetMeasurement = lengthMeasurement.to(Units.FOOT); The API framework of the measurement unit also supports the creation and use of custom units.We can use the static method of the Unit class to create a custom unit.For example, the following code creates a custom unit that represents temperature: Unit<Temperature> celsius = Unit.builder().symbol("°C").name("Celsius").addLinearConversion(0, 32).addLinearConversion(100, 212).build(); By using a custom unit, we can use the measurement unit API framework to process the calculation and conversion of various measured units, so that the code is more readable and easy to maintain. In summary, the API framework of the measurement unit is a powerful and flexible tool in the Java class library to handle the calculation and conversion of various measurement units.Whether it is a predetermined measurement unit or a custom unit, this API framework can help developers to more easily perform the tasks related to the unit.