java 未定义数组类型的 copyOf 方法
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copyOf method undefined for the type Arrays
提问by Greg
elementData = Arrays.copyOf(elementData, newCapacity);
Gives error:
给出错误：
The method copyOf(Object[], int) is undefined for the type Arrays
方法 copyOf(Object[], int) 对于 Arrays 类型是未定义的
This was not a problem on my home computer, but at my school's it gives the error above. I'm guessing it's running an older JRE version - any workaround?
这在我的家用电脑上不是问题，但在我学校的电脑上却出现了上述错误。我猜它正在运行旧的 JRE 版本 - 有什么解决方法吗？
回答by BalusC
From the javadocs:
从javadocs：
Since:
1.6
自：
1.6
So yes, your school is apparently using Java 1.5 or older. Two solutions are:
所以是的，您的学校显然使用的是 Java 1.5 或更早版本。两种解决方案是：
- Upgrade it (however, I'd first consult the school's system admin ;) ).
- Write your own utility method which does the same task (it's open source(line 2908)).
- 升级它（但是，我会先咨询学校的系统管理员；））。
- 编写您自己的实用方法来完成相同的任务（它是开源的（第 2908 行））。
回答by Brian Roach
Arrays.copyOf()was introduced in 1.6.
Arrays.copyOf()在 1.6 中引入。
You'd need to create a new array of the size you need and copy the contents of the old array into it.
您需要创建一个所需大小的新数组，并将旧数组的内容复制到其中。
From: http://www.source-code.biz/snippets/java/3.htm
来自：http: //www.source-code.biz/snippets/java/3.htm
/**
* Reallocates an array with a new size, and copies the contents
* of the old array to the new array.
* @param oldArray the old array, to be reallocated.
* @param newSize the new array size.
* @return A new array with the same contents.
*/
private static Object resizeArray (Object oldArray, int newSize) {
int oldSize = java.lang.reflect.Array.getLength(oldArray);
Class elementType = oldArray.getClass().getComponentType();
Object newArray = java.lang.reflect.Array.newInstance(
elementType,newSize);
int preserveLength = Math.min(oldSize,newSize);
if (preserveLength > 0)
System.arraycopy (oldArray,0,newArray,0,preserveLength);
return newArray;
}
回答by akf
Arrays.copyOfwas introduced in 1.6. One work around would be to upgrade to 1.6. Another is to use System.arraycopy(see: http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html)
Arrays.copyOf在 1.6 中引入。一种解决方法是升级到 1.6。另一种是使用System.arraycopy（见：http: //java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html）
回答by bmargulies
Sounds like you have different versions of Java on different computers.
听起来您在不同的计算机上有不同版本的 Java。
Arrays.copyOfis new in Java 1.6.
Arrays.copyOf是新的Java 1.6。
