枚舉enum概念

枚舉是由一組固定常量組成的類型.

使用枚舉的好處:類型安全,易於輸入

枚舉可作爲switch()的形參

枚舉舉例:

//定義枚舉
public enum Unit {
U1,U2,U3   
}
/**********************/
//實體類
public class Student {
    private Unit unit; //枚舉類型的變量
    private String target;

  //省略setter/getter

  public Student(){   
  }
  public Student(Unit unit, String target) {
    this.unit = unit;
    this.target = target;
  }

}
/**********************/
import java.util.List;
import java.util.ArrayList;
public class Test {
    public static void main(String[] args) {
        List list = new ArrayList();
        list.add(new Student(Unit.U1,”興趣和入門”));
        list.add(new Student(Unit.U2,”原理和深入”));
        list.add(new Student(Unit.U3,”開發”));

    for (Student student : list) {
        System.out.println(student.getUnit()+"目標是："+student.getTarget());
    }   
  }

}