设一个二维数组为a[][],判断其为空的条件有以下三点:
1.数组首地址是否为空(a==null)
2.是否为{},也就是array.length==0的情况
3.是否为{{}},这时array.length=1,但是array[0].length==0。满足任意一个条件就可以返回false了。
//也就是
if(array==null||array.length==0||(array.length==1&&array[0].length==0))
return false;
下面是一些检验:
int a[][];
int b[][] = {};
int c[][] = {{}};
System.out.println(a);
//The local variable a may not have been initialized,会报错,未被初始化
System.out.println(a.length);
//The local variable a may not have been initialized,会报错,未被初始化
System.out.println(a[0].length);
//The local variable a may not have been initialized,会报错,未被初始化
System.out.println(b);
//[[I@2a139a55
System.out.println(b.length);
//0
System.out.println(b[0].length);
//java.lang.ArrayIndexOutOfBoundsException: 会抛出异常,我认为是给了一个中括号,系统认为是一维数组,所以越界异常
System.out.println(c);
//[[I@15db9742,打印的是地址
System.out.println(c.length);
//1
System.out.println(c[0].length);
//0
参考:https://blog.csdn.net/severusyue/article/details/51694916