Java 使用枚举类型数据的例子，java枚举类型例子,枚举(enum)是JDK

Java 使用枚举类型数据的例子，java枚举类型例子,枚举(enum)是JDK

枚举(enum)是JDK 1.5 后新增的特性

public enum Planet {  MERCURY (3.303e+23, 2.4397e6),  VENUS   (4.869e+24, 6.0518e6),  EARTH   (5.976e+24, 6.37814e6),  MARS    (6.421e+23, 3.3972e6),  JUPITER (1.9e+27,   7.1492e7),  SATURN  (5.688e+26, 6.0268e7),  URANUS  (8.686e+25, 2.5559e7),  NEPTUNE (1.024e+26, 2.4746e7),  PLUTO   (1.27e+22,  1.137e6);  private final double mass;   // in kilograms  private final double radius; // in meters  Planet(double mass, double radius) {      this.mass = mass;      this.radius = radius;  }  public double mass()   { return mass; }  public double radius() { return radius; }  // universal gravitational constant  (m3 kg-1 s-2)  public static final double G = 6.67300E-11;  public double surfaceGravity() {      return G * mass / (radius * radius);  }  public double surfaceWeight(double otherMass) {      return otherMass * surfaceGravity();  }}// Example usage (slight modification of Sun's example):public static void main(String[] args) {    Planet pEarth = Planet.EARTH;    double earthRadius = pEarth.radius(); // Just threw it in to show usage    // Argument passed in is earth Weight.  Calculate weight on each planet:    double earthWeight = Double.parseDouble(args[0]);    double mass = earthWeight/pEarth.surfaceGravity();    for (Planet p : Planet.values())       System.out.printf("Your weight on %s is %f%n",                         p, p.surfaceWeight(mass));}//该片段来自于http://byrx.net