javaWeb(二)单例模式

-首先:

-1将构造方法私有化

-2.定义一个静态成员方法

-饥饿模式

直接创建一个对象出来

private Student(){}

private static Student student = new Student();

publicstatic Student getInstance(){

return student;

}

-慵懒模式:

只有第一个使用的时候才开始创建一个对象

private static Teacher teacher = null;

private static Object block = new Object();

private Teacher(){}

public Teacher getInstance(){

if(teacher==null)

synchronized(block){

if(teacher==null){

teacher = new Teacher();

return teacher;