工厂模式（懒汉式、饿汉式）

package factory;

/**

 * 饿汉式工厂

 * 

 * @ClassName: Factory1.java

 * @Description: 不管你用不用，进来后直接就帮你创建对象

 * @Author lyf

 * @Date 2017年3月10日 上午9:33:37

 *

 */

public class Factory1 {

private Factory1() {

}
private static Factory1 factory1 = new Factory1();

public static Factory1 getInstance() {

return factory1;

}

}

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package factory;

/**

 * 懒汉式工厂

 * 

 * @ClassName: Factory2.java

 * @Description: 不立即生成，存在线程不安全，所以上同步锁

 * @Author lyf

 * @Date 2017年3月10日 上午9:35:43

 *

 */

public class Factory2 {

private Factory2() {

}

private static Factory2 factory2 = null;

private synchronized static Factory2 getInstance() {
if (factory2 == null) {
factory2 = new Factory2();
}
return factory2;

}

}