Java:如何初始化String []? [英] Java: how to initialize String[]?

问题描述

错误

% javac  StringTest.java 
StringTest.java:4: variable errorSoon might not have been initialized
        errorSoon[0] = "Error, why?";

代码

public class StringTest {
        public static void main(String[] args) {
                String[] errorSoon;
                errorSoon[0] = "Error, why?";
        }
}

推荐答案

您需要初始化 errorSoon，如错误消息所示，您只有

You need to initialize errorSoon, as indicated by the error message, you have only declared it.

String[] errorSoon;                   // <--declared statement
String[] errorSoon = new String[100]; // <--initialized statement

您需要初始化数组，以便可以在开始设置索引之前为元素 分配正确的内存存储.

You need to initialize the array so it can allocate the correct memory storage for the String elements before you can start setting the index.

如果仅 声明数组(如您所做的那样)，则不会为String元素分配内存，而只会为errorSoon分配引用句柄，并且在您执行此操作时会抛出错误尝试在任何索引处初始化变量.

If you only declare the array (as you did) there is no memory allocated for the String elements, but only a reference handle to errorSoon, and will throw an error when you try to initialize a variable at any index.

作为旁注，您还可以将大括号内的String数组初始化为{ }，

As a side note, you could also initialize the String array inside braces, { } as so,

String[] errorSoon = {"Hello", "World"};

等效于

String[] errorSoon = new String[2];
errorSoon[0] = "Hello";
errorSoon[1] = "World";

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