2019獨角獸企業(yè)重金招聘Python工程師標準>>>

1、確保一個類只有一個實例，并提供一個全局的訪問點

2、飽漢式單例實現(xiàn)

package?com.shma.singleton;/***?飽漢式單例實現(xiàn)*?@author?admin**/ public?class?Singleton01?{private?static?Singleton01?uniqueInstance?=?new?Singleton01();private?Singleton01()?{}public?static?Singleton01?getInstance()?{return?uniqueInstance;}? }

3、餓漢式單例實現(xiàn)

package?com.shma.singleton;/***?餓漢式單例雙鎖機制*?@author?admin**/ public?class?Singleton02?{private?volatile?static?Singleton02?uniqueInstance?=?null;private?Singleton02()?{}public?static?Singleton02?getInstance()?{if(uniqueInstance?==?null)?{synchronized?(Singleton02.class)?{if(uniqueInstance?==?null)?{uniqueInstance?=?new?Singleton02();}}}return?uniqueInstance;} }

4、實現(xiàn)巧克力鍋爐類，巧克力鍋爐是一個單例類

package?com.shma.singleton.chocolate;/***?巧克力加工鍋爐類*?@author?admin**/ public?class?ChocolateBoiler?{//記錄鍋爐內(nèi)原料是否為空private?boolean?empty?=?false;//記錄鍋爐內(nèi)原料是否煮沸private?boolean?boiled?=?false;private?volatile?static?ChocolateBoiler?uniqueInstance?=?null;private?ChocolateBoiler()?{}public?static?ChocolateBoiler?getInstance()?{if(uniqueInstance?==?null)?{synchronized?(ChocolateBoiler.class)?{if(uniqueInstance?==?null)?{uniqueInstance?=?new?ChocolateBoiler();}}}System.out.println("Returning?instance?of?Chocolate?Boiler");return?uniqueInstance;}/***?裝滿鍋爐*?原料為空*/public?void?fill()?{if?(isEmpty())?{empty?=?false;boiled?=?false;//?fill?the?boiler?with?a?milk/chocolate?mixture}}/***?排出成品*?原料不能為空并且已經(jīng)被煮沸*/public?void?drain()?{if?(!isEmpty()?&&?isBoiled())?{//?drain?the?boiled?milk?and?chocolateempty?=?true;}}/***?煮沸方法*?條件是鍋爐原料不能為空并且沒有被煮沸過*/public?void?boil()?{if?(!isEmpty()?&&?!isBoiled())?{//?bring?the?contents?to?a?boilboiled?=?true;}}public?boolean?isEmpty()?{return?empty;}public?boolean?isBoiled()?{return?boiled;} }package?com.shma.singleton.chocolate;public?class?ChocolateController?{public?static?void?main(String[]?args)?{ChocolateBoiler?boiler?=?ChocolateBoiler.getInstance();//裝入原料boiler.fill();//煮沸boiler.boil();//排出boiler.drain();//?will?return?the?existing?instanceChocolateBoiler?boiler2?=?ChocolateBoiler.getInstance();} }

轉(zhuǎn)載于:https://my.oschina.net/shma1664/blog/400838

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