我必须以惰性初始化“静态类持有人惯用语单例”模式编写此代码
public class DateComparator{
private static DateComparator instance = null;
public static DateComparator getInstance()
{
if(instance == null)
instance = new DateComparator();
return instance;
}
}
这是我更改的代码:
public class DateComparator{
private static DateComparator container = null;
private static class DateComparatorHolder {
private static DateComparator instance=createInstance();
}
private static DateComparator createInstance() {
if(container == null)
//container = new DateComparator();
return new DateComparator();
}
public static DateComparator getInstance()
{
return DateComparatorHolder.instance;
}
最佳答案
不需要container
变量或createInstance()
:
public class DateComparator{
private static class DateComparatorHolder {
private static final DateComparator instance= new DateComparator();
}
public static DateComparator getInstance()
{
return DateComparatorHolder.instance;
}
}
就这样。