不可变(immutable)类的意思是创建该类的实例后,,该实例的Field是不可改变的,Java提供的8个包装类和java.lang.String类都是不可变类。
如果需要创建自定义的不可变类,可遵守如下规则:
AddressTest { 2 3 } Address { String detail; String postcode; Address() {10this.detail = “”;11this.postcode = “”;12 } Address(String detail, String postcode) {15this.detail = detail;16this.postcode = postcode;17 } String getDetail() {.detail;22 }23public String getPostcode() {.postcode;25 } equals(Object obj) {29 ……30 } hashCode() {33return detail.hashCode() + postcode.hashCode() * 31;34 }35 36 }你不勇敢,没人替你坚强!