单例模式代码

1、懒汉式：

			public class Single {
					private static Single s = null;
					private Single(){};
					public static Single getInstance(){
						if(s == null){
							synchronized (Single.class) {
								if(s == null)
								s = new Single();
							}
						}
						return s;
				}
			}

2、饿汉式：

				public class Single {
						private static Single s = new Single();;
						private Single(){};
						public static Single getInstance(){
							return s;
					}
				}