Java静态类初始化块介绍

使用初始化块初始化实例变量。但是，静态初始化块只能初始化静态实例变量。这些块仅在加载类时执行一次。一个类中可以有多个静态初始化块，按照它们在程序中出现的顺序被调用。

下面给出了一个演示 Java 中的静态初始化块的程序：

例子

public class Demo {
   static int[] numArray = new int[10];
   static {
      System.out.println("Running static initialization block.");
      for (int i = 0; i < numArray.length; i++) {
         numArray[i] = (int) (100.0 * Math.random());
      }
   }
   void printArray() {
      System.out.println("The initialized values are:");
      for (int i = 0; i < numArray.length; i++) {
         System.out.print(numArray[i] + " ");
      }
      System.out.println();
   }
   public static void main(String[] args) {
      Demo obj1 = new Demo();
      System.out.println("For obj1:");
      obj1.printArray();
      Demo obj2 = new Demo();
      System.out.println("\nFor obj2:");
      obj2.printArray();
   }
}

输出

Running static initialization block.
For obj1:
The initialized values are:
40 75 88 51 44 50 34 79 22 21
For obj2:
The initialized values are:
40 75 88 51 44 50 34 79 22 21