Arrays.deepToString() 方法同时适用于基元数组和对象数组

Arrays.deepToString() 方法同时适用于基元数组和对象数组：

import java.util.*;

public class MultiDimWrapperArray {
  public static void main(String[] args) {
    Integer[][] a1 = { // Autoboxing
      { 1, 2, 3, },
      { 4, 5, 6, },
    };
    Double[][][] a2 = { // Autoboxing
      { { 1.1, 2.2 }, { 3.3, 4.4 } },
      { { 5.5, 6.6 }, { 7.7, 8.8 } },
      { { 9.9, 1.2 }, { 2.3, 3.4 } },
    };
    String[][] a3 = {
      { "The", "Quick", "Sly", "Fox" },
      { "Jumped", "Over" },
      { "The", "Lazy", "Brown", "Dog", "&", "friend" },
    };
    System.out.println(
      "a1: " + Arrays.deepToString(a1));
    System.out.println(
      "a2: " + Arrays.deepToString(a2));
    System.out.println(
      "a3: " + Arrays.deepToString(a3));
  }
}
/* Output:
a1: [[1, 2, 3], [4, 5, 6]]
a2: [[[1.1, 2.2], [3.3, 4.4]], [[5.5, 6.6], [7.7,
8.8]], [[9.9, 1.2], [2.3, 3.4]]]
a3: [[The, Quick, Sly, Fox], [Jumped, Over], [The,
Lazy, Brown, Dog, &, friend]]
*/

同样的，在 Integer 和 Double 数组中，自动装箱可为你创建包装器对象。