Java 7切换语句，字符串不起作用 [英] Java 7 switch statement with strings not working

问题描述

根据 Java教程，在 Java SE 7 及更高版本，您可以在switch语句的表达式中使用String对象。

According to The Java Tutorials, in Java SE 7 and later, you can use a String object in the switch statement's expression.

String s = ...
switch(s){
    //do stuff
}

但这是真的吗？我安装了JRE并将其添加到Eclipse项目的构建路径，但是我收到以下编译时错误：

But is this true? I've installed the JRE and added it to the build path of my Eclipse project, but I'm getting the following compile-time error:

无法打开
String类型的值。只允许可转换的int值或
枚举常量

Cannot switch on a value of type String. Only convertible int values or enum constants are permitted

此外，我认为自从我被能够使用它的 java.nio.file.Files 类，以及 JLayer 。

Also, I think I've got it configured correctly since I was able to use its java.nio.file.Files class, as well as JLayer.

任何想法？

推荐答案

虽然JDT团队确实实施了启用字符串功能，Java 7的支持将不会在Eclipse 3.7.1之前：

While it is true that the JDT team has implemented the Switch on String feature, the support for Java 7 won't be before Eclipse 3.7.1:

请参阅 bug 288548 ：

由于JSR-292（Invoke Dynamic）和JSR-334（项目硬币）
和由于Java 7的正式发布日期（2011年7月28日）在3.7
之后，我们不得不将Java 7的支持推迟到3.7.1。还没有决定
是否可以作为3.7.1下载或单独的
功能更新的一部分。

Due to late availability of JSR-292 (Invoke Dynamic) and JSR-334 (Project Coin) and due to the official release date (July 28, 2011) of Java 7 being after 3.7 ships we had to defer the Java 7 support to 3.7.1. It has not yet been decided whether this will be available as part of the 3.7.1 downloads or as separate feature update.

工作由于Java 7功能目前正在BETA_JAVA7
分支中进行，我们将为稳定的版本提供单独的更新，以便
提供对有兴趣的方面的Java 7功能的早期访问。 p>

The work for the Java 7 features is currently in progress in the 'BETA_JAVA7' branch and we will deliver separate updates for the stable builds in order to provide early access to the Java 7 features for interested parties.

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