package com;public interface ITest { public void test();}===========================================package com;public class Test1 implements ITest { @Override public void test() { // TODO Auto-generated method stub System.out.println("調(diào)用成功"); }}======================================package com;public class Test2 { private static ITest iTest; public static void main(String[] args) { // TODO Auto-generated method stub iTest.test(); } public ITest getiTest() { return iTest; } public void setiTest(ITest iTest) { this.iTest = iTest; } }為什么返回值為null???第一次用sf,求大神指點(diǎn)
4 回答
慕容森
TA貢獻(xiàn)1853條經(jīng)驗(yàn) 獲得超18個(gè)贊
你只是聲明一個(gè)名為iTest的變量, 并未給其實(shí)例化, 在JAVA語(yǔ)言中通常是用NEW這個(gè)關(guān)鍵字來(lái)實(shí)例化一個(gè)對(duì)象的.
把你上面的代碼修改成如下的:
package com;
public class Test2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
ITest tmp = new Test1();
tmp.test();
}
}
寶慕林4294392
TA貢獻(xiàn)2021條經(jīng)驗(yàn) 獲得超8個(gè)贊
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