Java:如何初始化 String[]?

沃梦达教程 Java问题

2022-01-01

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

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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

你需要初始化 errorSoon，如错误消息所示，您只有声明了.

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，以便它可以为 String 元素分配正确的内存存储在您可以开始设置索引之前.

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.

如果您仅声明数组(如您所做的那样)，则不会为 String 元素分配内存，而只有 errorSoon，并且当您尝试在任何索引处初始化变量时将引发错误.


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，您还可以在大括号内初始化 String 数组，{ } 就是这样，
As a side note, you could also initialize the String array inside braces, { } as so,
String[] errorSoon = {"Hello", "World"};

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


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