如何克隆缓存中取出的内容?

[专业二三维GIS]

在使用JCS时,从缓存中取出一个对象后,如果修改这个对象的属性值,缓存中的对象的相应属性值也会变化,可见通过JCS的get方法从缓存中取出的只是一个引用,如下:
JCS empcache=JCS.getInstance("empcache");
Employee employee=empcache.get("john");
System.out.print(employee.getDepartment()); //假设此时输出结果为"HR"
employee.setDepartment("Market");
System.out.print(employee.getDepartment()); //输出结果为"market"
System.out.print(empcache.get("john").getDepartment()); //这里的输出结果也变成了"market",但我不希望它改变.


我希望的结果是将缓存对象clone(深度复制)一个副本,当副本改变时缓存对象不会受到任何影响.
我知道可以自己重写Employee的clone()方法来实现对Employee对象的深度复制,但这样做很麻烦,而且不够灵活.不知道JCS里面有没有什么配置或方法使得从缓存中取出的是一个副本? 当然,除JCS之外的其它缓存技术如果能实现这种需求的话也请推荐一下.

[BearKin]

你要改变该对象的什么属性值? 该对象里面对象的属性值也要改么? 如果不需要改的话 不知道BeanUtils用来复制个Bean是不是更快些呢?

[BearKin]

引用 1 楼 bearkin 的回复:

你要改变该对象的什么属性值? 该对象里面对象的属性值也要改么? 如果不需要改的话 不知道BeanUtils用来复制个Bean是不是更快些呢?

如果说里面的对象也要COPY的话...想想..

[专业二三维GIS]

我早试过了,BeanUtils只能币制一些基本数据类型的值,并不能实现深度复制.

[BearKin]

那俺就不知道了 连里面的对象属性都要COPY的话...恩..

[BearKin]

import java.lang.reflect.Field;

public class ObjectCopy {

	public static void main(String[] args) throws Exception {
		A baseObject = new A(new B(new C("bString1", "bString2"), 1, 2), new C(
				"cString1", "cString2"));
		A copyObject = (A) copyObject(baseObject, "java.lang.Integer",
				"java.lang.String");

		System.out.println(baseObject);
		System.out.println(copyObject);
	}

	/**
	 * COPY对象(毛病还是很多的。。)
	 * 
	 * @author Lv9
	 * @since 2010.03.09
	 * @param Object baseObject 将要被COPY的对象
	 * @param String[] noCopyClassNames 对象内不必深COPY的属性声明(如java.lang.Integer)
	 */
	public static Object copyObject(Object baseObject,
			String... noCopyClassNames) throws Exception {
		Object copyObject = baseObject.getClass().newInstance();

		Field[] fields = baseObject.getClass().getDeclaredFields();

		for (Field field : fields) {
			field.setAccessible(true);
			if (checkClassType(field.getType().getName(), noCopyClassNames)) {
				field.set(copyObject, field.get(baseObject));
			} else {
				field.set(copyObject, copyObject(field.get(baseObject),
						noCopyClassNames));
			}
		}
		return copyObject;
	}

	public static boolean checkClassType(String className,
			String[] noCopyClassNames) {
		for (String noCopyClassName : noCopyClassNames) {
			if (className.equals(noCopyClassName)) {
				return true;
			}
		}
		return false;
	}
}

class A {
	private B b;
	private C c;

	public A() {

	}

	public A(B b, C c) {
		this.b = b;
		this.c = c;
	}

	public B getB() {
		return b;
	}

	public void setB(B b) {
		this.b = b;
	}

	public C getC() {
		return c;
	}

	public void setC(C c) {
		this.c = c;
	}

	@Override
	public String toString() {
		return "[A: b = " + b + ",c = " + c + ",hashCode = " + hashCode() + "]";
	}
}

class B {
	private C c;
	private Integer int1;
	private Integer int2;

	public B() {

	}

	public B(C c, Integer int1, Integer int2) {
		this.c = c;
		this.int1 = int1;
		this.int2 = int2;
	}

	public C getC() {
		return c;
	}

	public void setC(C c) {
		this.c = c;
	}

	public Integer getInt1() {
		return int1;
	}

	public void setInt1(Integer int1) {
		this.int1 = int1;
	}

	public Integer getInt2() {
		return int2;
	}

	public void setInt2(Integer int2) {
		this.int2 = int2;
	}

	@Override
	public String toString() {
		return "[B: int1 = " + int1 + ",int2 = " + int2 + ",c = " + c
				+ ",hashCode = " + hashCode() + "]";
	}
}

class C {
	private String string1;
	private String string2;

	public C() {

	}

	public C(String string1, String string2) {
		this.string1 = string1;
		this.string2 = string2;
	}

	public String getString1() {
		return string1;
	}

	public void setString1(String string1) {
		this.string1 = string1;
	}

	public String getString2() {
		return string2;
	}

	public void setString2(String string2) {
		this.string2 = string2;
	}

	@Override
	public String toString() {
		return "[C: string1 = " + string1 + ",string2 = " + string2
				+ ",hashCode = " + hashCode() + "]";
	}
}

刚写的 您运行下吧 我查看了结果 思路大概就是这样吧..

[专业二三维GIS]

晕了,我就是不想写代码才发问的,你的这种方法我也想过.
我只是想知道直接用JCS或其它缓存组件有没有复制内容的功能.

不过非常感谢你,辛苦了!

[BearKin]

代码一共没多少行 写就写了被..