Guide to use the API framework in the Java class library

Guide to use the API framework in the Java class library Overview: The measuring unit is a concept that is often used in measurement and measurement data, and the API framework of the measurement unit in the Java class library provides a convenient way to handle various measurement units and conduct unit conversion.This article will introduce how to use the measured unit API framework in the Java library, and provide some example code to help readers better understand its usage. 1. Introduce the API framework of the measurement unit First, we need to introduce the API framework of the measurement unit in the Java project.The Java SE 8 and above versions have built up the javax.measure package, so we only need to import the corresponding class in the code to start using it. import javax.measure.*; import javax.measure.quantity.*; 2. Define the measurement unit The API framework of the measurement unit provides many built -in measurement units, such as length, quality, time, etc.However, we can also define their own measurement units by inheriting the quantity class.Below is an example of a custom temperature measurement unit: public class Temperature extends Quantity<Temperature> { public Temperature(Number number, Unit<Temperature> unit) { super(number, unit); } } In the above example, we created a TEMPERATURE class by inheriting the QUNTITITY class to represent temperature.The constructor accepts a Number object and a unit object, respectively represents the value and measurement unit of the temperature, respectively. 3. Basic operation Using the measured unit API framework, we can perform various basic operations, such as unit conversion, numerical comparison, etc.Here are some common basic operation examples: // Unit conversion Quantity<Length> distanceInMeters = Quantities.getQuantity(10, Units.METER); Quantity<Length> distanceInFeet = distanceInMeters.to(Units.FOOT); // Numeric comparison Quantity<Temperature> temperature1 = Quantities.getQuantity(25, Units.CELSIUS); Quantity<Temperature> temperature2 = Quantities.getQuantity(77, Units.FAHRENHEIT); boolean isEqual = temperature1.equals(temperature2); // false // Numerical operations Quantity<Mass> mass1 = Quantities.getQuantity(5, Units.KILOGRAM); Quantity<Mass> mass2 = Quantities.getQuantity(2, Units.POUND); Quantity<Mass> totalMass = mass1.add(mass2); In the above examples, we first convert a length value from rice to feet, and then compare whether the two temperature values are equal. Finally, calculate the sum of the two mass values. 4. Format output The API framework of the measurement unit also provides some methods to format the output measurement unit data.We can follow the units and accuracy that need to specify the output.The following is an example of an output temperature value: Quantity<Temperature> temperature = Quantities.getQuantity(25, Units.CELSIUS); System.out.println(temperature.to(Units.FAHRENHEIT).toString()); // 77.0 °F In the above example, we converted the degree of degrees Celsius to Fahrenheit and output in the form of a string. Summarize: The API framework in the JAVA library is a powerful tool for processing the conversion of the unit and unit to conversion.This article introduces how to use this framework and provide some example code to help readers better understand its usage.By flexibly applying the API framework of the unit, we can easily manage and operate various measurement unit data.