java之 惰性初始化
阿新 • • 發佈:2018-11-06
class Soap { private String s; Soap(){ System.out.println("Soap()"); s="Constructed"; } public String toString() { return s; } } class Bath { private String s1 ="happy", s2 = "happy", s3,s4; private Soap castille; private int i; private float toy; public Bath() { System.out.println("Inside Bath()"); s3 = "Joy"; toy = 3.14f; castille = new Soap(); } { i=47; } public String toString(){ if(s4==null) s4 = "Joy"; return "s1 = " + s1 +"\n"+ "s2 = " + s2 +"\n"+ "s3 = " + s3 +"\n"+ "s4 = " + s4 +"\n"+ "i = " + i +"\n"+ "toy = " + toy +"\n"+ "castille =" + castille; } public static void main(String[] args) { Bath b = new Bath(); System.out.println(b); } }
輸出
Inside Bath() Soap() s1 = happy s2 = happy s3 = Joy s4 = Joy i = 47 toy = 3.14 castille =Constructed
來自thinking in java