Java 7切换语句,字符串不起作用

根据 The Java Tutorials,在 Java SE 7和更高版本中,您可以在switch语句的表达式中使用String对象.

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

但这是真的吗？我已经安装了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：

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

此外,我想我已经配置正确,因为我可以使用其java.nio.file.Files类以及JLayer.

有任何想法吗？

解决方法

虽然JDT团队确实实施了 Switch on String feature,但对Java 7的支持不会在Eclipse 3.7.1之前：

见bug 288548：

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.

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.