在运行时执行java命令

Question

Process process2 = Runtime.getRuntime().exec(new String[]{"javac","-g:vars","/Users/amol/Documents/Java/a.java"});
Process process3 = Runtime.getRuntime().exec(new String[]{"javap","-l","-c","/Users/amol/Documents/Java/a"});

I tried to run this code but I am facing a strange problem. It compiles correctly (means the first line compiles the program) but the second line gives an error saying that 'a' not found . However when I checked the given directory a.class file was created correctly. How should I correctly run the second line?

Answer 1

javap takes a class name, not a filename. You probably want to execute:

javap -l -c -classpath /Users/amol/Documents/Java a

(Split that into string arguments appropriately, of course.)

Note that this will still fail if a is in a package - or if the class in a.java isn't actually a at all (which is valid for non-public classes). In both of these cases, you'd need to determine the classes involved, probably by building into an empty directory and finding out which files are produced by javac .

Answer 2

您可能必须为javap指定类路径参数，直到该类的目录。

Process process3 = Runtime.getRuntime().exec(new String[]{"javap","-l","-c","-classpath  \"/Users/amol/Documents/Java/\"","a"});