java static 靜態變數初始化

java static 靜態變數初始化
static final int NUMBER_OF_MONTHS = 12;
static final float PI = (float) 22 / 7;
如果你想使一個靜態變數在其它地方可以引用的話，如下

public static final int NUMBER_OF_MONTHS = 12;
public static final float PI = (float) 22 / 7;

寫在函數中

public class MainClass {

  public static void main(String[] arg) {
    final int FEET_PER_YARD = 3;          // Constant values
    final double MM_PER_INCH = 25.4;      // that cannot be changed

    System.out.println(FEET_PER_YARD);
    System.out.println(MM_PER_INCH);
   
  }

}

靜態變數如何初始化
Java類中可以定義一個static塊，用於靜態變數的初始化。如：

 

public class Test {   
    public static int _i;   
    static {   
         _i = 10;   
     }   
}  
public class Test { public static int _i; static { _i = 10; } }

當然最常用的初始化靜態變數的操作是在聲明變數時直接進行賦值操作。如：

 

public class Test {   
    public static int _i = 10;   
}  
public class Test { public static int _i = 10; }