javaWeb(二)單例模式

-首先:

-1将構造方法私有化

-2.定義一個靜态成員方法

-饑餓模式

直接建立一個對象出來

private Student(){}

private static Student student = new Student();

publicstatic Student getInstance(){

return student;

}

-慵懶模式:

隻有第一個使用的時候才開始建立一個對象

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;