Guava 提供 Arrays.concat(T[], T[], Class).

Class 参数的原因，仅供参考，是因为泛型数组有明显的上升趋势.如果你做了 Arrays.concat(Integer[], Long[])，你想要返回一个 Object[] 吗?还是Number[]?Guava 让你指定，所以没有歧义......而且因为所有替代方案都可能导致运行时不可预测的 ClassCastException.

The reason for the Class parameter, FYI, is because generic arrays have a distinct tendency to get upcast. If you did Arrays.concat(Integer[], Long[]), did you want an Object[] back? Or a Number[]? Guava makes you specify so there's no ambiguity...and because all of the alternatives can lead to unpredictable ClassCastExceptions at runtime.

(披露:我为 Guava 做出了贡献.)

(Disclosure: I contribute to Guava.)