关于枚举类的构造方法

输出结果： It is a account type
It is a account type
It is a account type
SAVING
解释：简而言之，枚举类有是三个实例，故调用三次构造方法，打印三次It is a account type 2.

public class EnumIndexTest {
enum Constants2 {
 Constants_A("枚举成员A"),
 Constants_B("枚举成员B"), 
 Constants_C("枚举成员C"), 
 Constants_D(3);
 private String description;
 private int i = 4;

 private Constants2() {

 }

private Constants2(String description){
this.description =  description;
}

private Constants2(int i) {
    this.i = this.i + i;
}

public String getDescription() {
     return description;
}

public int geti() {
      return i;
}

}
public static void main(String[] args) {
for(int i = 0;i < Constants2.values().length;i++){
 System.out.println(Constants2.values()[i]+"调用getDescription()方法为："+Constants2.values()[i].getDescription());
}
System.out.println(Constants2.valueOf("Constants_D")+"调用geti() 方法为："+Constants2.valueOf("Constants_D").geti());
}
}

输出结果： Constants_A调用getDescription()方法为：枚举成员A
Constants_B调用getDescription()方法为：枚举成员B
Constants_C调用getDescription()方法为：枚举成员C
Constants_D调用getDescription()方法为：null
Constants_D调用geti() 方法为：7