想用exec打开Win7自带的播放器wmplayer.exe，于是
Runtime rt = Runtime.getRuntime();
rt.exec("wmplayer.exe");
编译通过，运行时提如下：
Exception in thread "main" java.io.IOException: Cannot run program "wmplayer.exe
": CreateProcess error=2, The system cannot find the file specified
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
at java.lang.Runtime.exec(Runtime.java:620)
at java.lang.Runtime.exec(Runtime.java:450)
at java.lang.Runtime.exec(Runtime.java:347)
at RuntimeDemo.main(RuntimeDemo.java:9)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find th
e file specified
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.<init>(ProcessImpl.java:386)
at java.lang.ProcessImpl.start(ProcessImpl.java:137)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
... 4 more
于是去设置环境变量：
首先新建一个名为WMPLAYER的环境变量，将wmplayer.exe的路径 C:\Program Files\Windows Media Player 放到里边
然后在Path的最后加上 ;%WMPLAYER%
编译通过，运行时仍出现同上的提示，这是为什么？我哪里配错了？