可变参数重载的问题

来源：互联网发布：中国互联网金融数据编辑：程序博客网时间：2024/06/05 15:31

1. 可变参数相当于传数组参数，参数为0相当于数组为空

2. 当可变参数方法重载的时候，如果实际传参为0个，编译将不通过(无法分辨调用的哪个方法)

package com.yjq.cn.initialize;/** *  可变参数 */public class VarArgsTest {static void fc(int i, String... str) {System.out.print("fc.args : [" + i + " ");for(String s : str) {System.out.print(s + " ");}System.out.println("]; args.length: " + str.length);}//重载1static void f(Integer... args) {System.out.print("first");for(Integer i : args) {System.out.print(" " + i);}System.out.println();}//重载2static void f(Character... args) {System.out.print("second");for(Character c : args) {System.out.print(" " + c);}System.out.println();}//重载3static void f(Long... args) {System.out.print("third");for(Long l : args) {System.out.print(" " + l);}System.out.println();}public static void main(String[] args) {fc(1, "one");fc(2, "two", "three");//可变参数个数可以传0个fc(0);System.out.println("--------------------");//重载的情况f('a', 'b', 'c');f(1);f(2, 1);f(0);f(0L);//f();  //此时编译报错 The method f(Integer[]) is ambiguous for the type VarArgsTest}}

//output
fc.args : [1 one ]; args.length: 1fc.args : [2 two three ]; args.length: 2fc.args : [0 ]; args.length: 0--------------------second a b cfirst 1first 2 1first 0third 0