Guava教程
LongMath提供long基础类型的实用方法。
以下是com.google.common.math.LongMath类的声明:
@GwtCompatible(emulated=true)
public final class LongMath
extends Object
方法
方法继承
这个类继承了以下类方法:java.lang.Object
使用所选择的任何编辑器创建下面的java程序 C:/> Guava
GuavaTester.java
import java.math.RoundingMode;
import com.google.common.math.LongMath;
public class GuavaTester {
public static void main(String args[]){
GuavaTester tester = new GuavaTester();
tester.testLongMath();
}
private void testLongMath(){
try{
System.out.println(LongMath.checkedAdd(Long.MAX_VALUE, Long.MAX_VALUE));
}catch(ArithmeticException e){
System.out.println("Error: " + e.getMessage());
}
System.out.println(LongMath.divide(100, 5, RoundingMode.UNNECESSARY));
try{
//exception will be thrown as 100 is not completely divisible by 3 thus rounding
// is required, and RoundingMode is set as UNNESSARY
System.out.println(LongMath.divide(100, 3, RoundingMode.UNNECESSARY));
}catch(ArithmeticException e){
System.out.println("Error: " + e.getMessage());
}
System.out.println("Log2(2): "+LongMath.log2(2, RoundingMode.HALF_EVEN));
System.out.println("Log10(10): "+LongMath.log10(10, RoundingMode.HALF_EVEN));
System.out.println("sqrt(100): "+LongMath.sqrt(LongMath.pow(10,2), RoundingMode.HALF_EVEN));
System.out.println("gcd(100,50): "+LongMath.gcd(100,50));
System.out.println("modulus(100,50): "+LongMath.mod(100,50));
System.out.println("factorial(5): "+LongMath.factorial(5));
}
}
验证结果
使用javac编译器编译如下类
C:\Guava>javac GuavaTester.java
现在运行GuavaTester看到的结果
C:\Guava>java GuavaTester
看到结果
Error: overflow
20
Error: mode was UNNECESSARY, but rounding was necessary
Log2(2): 1
Log10(10): 1
sqrt(100): 10
gcd(100,50): 50
modulus(100,50): 0
factorial(5): 120
转载自并发编程网-ifeve.com