Java能设置参数默认值吗

不能，死心吧，只能使用可变参数，如下：

@Test
    public void test1() {
       var("张3","打球","吃饭");
       var("张3");
    }

    //默认爱好，相当于默认值
    static final String default_hobby = "打球";
    
    static void var(String name, String... hobby) {
        if (hobby.length == 0) {
            //hobby参数默认值
            System.out.println(name + "喜欢" + default_hobby);
        } else {
            System.out.println(name + "喜欢" + Stream.of(hobby).collect(Collectors.joining()));
        }
    }