享元模式

Flyweight

重复利用对象

String s1 = "abc";
String s2 = "abc";
String s3 = new String("abc");
String s4 = new String("abc");

System.out.println(s1 == s2);// true
System.out.println(s1 == s3);// false
System.out.println(s3 == s4);// false
System.out.println(s3.intern() == s1);// true
System.out.println(s3.intern() == s4.intern());// true