blocks|key|2414811|text|您通常不能在Java中这样做--当然，对于局部变量也不能这样做。通常，如果要将字符串或整数映射到值，则应使用Map<String,+...>、Map<Integer,+...>或数组，而不是单独的变量。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2414812|例如，可以使用反射或静态变量来实现这一点，但我强烈建议您不要这样做。基本上，您应该将变量视为单独的存储位置，这些存储位置在编译时碰巧有名称，而不是从名称到值的映射。如果需要后者，请显式创建映射。|2414813|entityMap^0|1I|G|1Z|H|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

You can't generally do this in Java - certainly not for local variables. Normally if you want to map a string or integer to a value, you should use a <code>Map&lt;String, ...&gt;</code>, a <code>Map&lt;Integer, ...&gt;</code> or an array instead of separate variables.

For instance or static variables you could use reflection to achieve this, but I would strongly advise you not to. Basically you should treat variables as separate storage locations which happen to have names at compile time, not a mapping from names to values. If you need the latter, create that mapping explicitly.

blocks|key|693354|text|也许您想看看数组：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|693355|String[]+texts+=+{+"Hello",+"world"};

for+(int+i=0;+i<2;+i%2B%2B)
++++System.out.println(texts[i]);

for+(String+text+:+texts)
+++System.out.println(text);|code-block|syntax|javascript|693356|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Maybe you want to look at arrays:

<pre><code>String[] texts = { "Hello", "world"};

for (int i=0; i&lt;2; i++)
 System.out.println(texts[i]);

for (String text : texts)
 System.out.println(text);
</code></pre>

blocks|key|2414861|text|您可以使用一个数组来完成这个任务：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2414862|String[]+text+=+new+String[2];
text[0]+=+"Hello";
text[1]+=+"world";

System.out.println(text[0]);
System.out.println(text[1]);|code-block|syntax|javascript|2414863|还可以使用变量对数组进行索引：|2414864|int+i+=+1;
System.out.println(text[i]);|2414865|Java通常不支持在运行时构造(本地)变量名。大多数(但不是所有)编程语言都是如此。|2414866|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You can do this using an array:

<pre><code>String[] text = new String[2];
text[0] = "Hello";
text[1] = "world";

System.out.println(text[0]);
System.out.println(text[1]);
</code></pre>

You can also index the array using a variable:

<pre><code>int i = 1;
System.out.println(text[i]);
</code></pre>

Java does not generally support constructing (local) variable names at runtime. This is true of most (but not all) programming languages.

blocks|key|693380|text|这是因为Java首先计算System.out.println(expr)中的表达式，然后将其转换为字符串。当Java计算表达式时，它遵循从左到右的规则.|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|693381|所以，你可以|693382|System.out.print("hello"%2B2);+//+hello2+++|code-block|syntax|javascript|693383|entityMap^0|C|O|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

It is because Java evaluates the expression inside <code>System.out.println(expr)</code> first, then convert it to a String. When Java evaluates the expression, it follows the left-to-right rule. 
So, you get 

<pre><code>System.out.print("hello"+2); // hello2 
</code></pre>

blocks|key|2414938|text|不能按名称访问局部变量，但可以按名称访问字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2414939|public+class+Tester+{
++++public+static+final+String+text+=+"Hello";
++++public+static+final+String+text2++=+"world";

++++public+static+void+main(String[]+args)+{
++++++++int+i+=+2;
++++++++System.out.println(Tester.class.getField("text").get(null));
++++++++System.out.println(Tester.class.getField("text"%2Bi).get(null));
++++}
}|code-block|syntax|javascript|2414940|由于明显的原因，这种做法是不被鼓励的。|2414941|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You cannot access local variable by name, however you can access fields by name.

<pre><code>public class Tester {
 public static final String text = "Hello";
 public static final String text2 = "world";

 public static void main(String[] args) {
 int i = 2;
 System.out.println(Tester.class.getField("text").get(null));
 System.out.println(Tester.class.getField("text"+i).get(null));
 }
}
</code></pre>

This practice is discouraged for obvious reasons.

<blockquote>
 Possible Duplicate: 
 <a href="https://stackoverflow.com/questions/3113040/use-a-variable-within-a-variable-java">Use a variable within a variable? Java</a> 
</blockquote>



Hi this is a general programming related question more so than a java question. If i have a program like this : 

<pre><code>public class tester {

 public static void main(String[] args) {
 int i = 2;
 String text = "Hello";
 String text2 = "world";

 System.out.println(text);
 System.out.println(text + i);
 } 
}
</code></pre>

I want to print "hello", then "world" but instead i print "hello" and then "hello2". is there anyway i can access the variable text2 by appending the counter i to the variable test? I need a solution for this for a much more complicated program i am working on

Thanks,
Matt

Programming variable question(java)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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 可能重复：嗨，这是一个与编程有关的一般问题，而不是一个java问题。如果我有这样的程序：public class tester {    public static void main(String[] args) {        int i = 2;        String text = "Hello";  ...

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