JAVA .clone方法示例分析

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public class CloneTest implements Cloneable {public long primitive;public Long box;public String name;public String interest[]; // 数组public Object object; // 这个对象无法clone，也没有意义去clonepublic Other oth; // 复杂对象，也需要实现Cloneable接口@Overridepublic Object clone() {CloneTest o = null;try {o = (CloneTest) super.clone();// 数组对象与 复杂对象需要进行深度复制o.interest = interest.clone();o.oth = (Other) oth.clone();// Object.clone()是protected方法，无法调用// o.object = object.clone();} catch (CloneNotSupportedException e) {e.printStackTrace();}return o;}public static void main(String[] args) throws Exception {CloneTest t = new CloneTest();t.primitive = 1;t.box = 1L;t.name = "leo";t.interest = new String[] { "aa", "bb" };t.oth = new Other();t.oth.other = "other";t.object = new Object();CloneTest t2 = (CloneTest) t.clone();t2.primitive = 2;t2.box = 2L;t2.name = "dongql";t2.interest[0] = "AA";System.out.print(t + "\t" + t.oth + "\t" + t.primitive + "\t" + t.box + "\t" + t.name + "\t" + t.interest[0]);System.out.println("\t" + t.interest[1] + "\t" + t.object + "\t" + t.oth.other);System.out.print(t2 + "\t" + t2.oth + "\t" + t2.primitive + "\t" + t2.box + "\t" + t2.name + "\t" + t2.interest[0]);System.out.println("\t" + t2.interest[1] + "\t" + t2.object + "\t" + t2.oth.other);// 修改引用// 不进行深度复制这个也不会影响t.interest与t.object值// 原因是t2.interest与t.object的指针被修改，而不是值被修改// t2.interest = new String[]{"c", "d"};t2.object = new Object();// 修改值t2.interest[1] = "BB";t2.oth.other = "OTHER";System.out.print(t2 + "\t" + t2.oth + "\t" + t2.primitive + "\t" + t2.box + "\t" + t2.name + "\t" + t2.interest[0]);System.out.println("\t" + t2.interest[1] + "\t" + t2.object + "\t" + t2.oth.other);}}class Other implements Cloneable {public String other;@Overridepublic Object clone() {Other o = null;try {o = (Other) super.clone();} catch (CloneNotSupportedException e) {e.printStackTrace();}return o;}}

运行结果：

kk.CloneTest@1888759kk.Other@6e140811leoaabbjava.lang.Object@e53108otherkk.CloneTest@f62373kk.Other@19189e122dongqlAAbbjava.lang.Object@e53108otherkk.CloneTest@f62373kk.Other@19189e122dongqlAABBjava.lang.Object@1f33675OTHER

分析总结：
复制需要实现java.lang.Cloneable接口，重写clone方法
原生类型会复制值，包装类与其它类对象复制的是引用，要实现对象复制得深度复制，如：o.oth = (Other) oth.clone();
重新new一个对象并赋值给原对象这个跟clone方法实际上做的是一件事，如：t2.object = new Object();

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