在Java中执行批处理文件会产生意外结果

Question

I have the following batch File : -

gcc temp.c -o temp.exe
pause

This batch file compiles a .c file. This batch script runs fine when executed by double clicking, but When I use java for that purpose, It gives me an error. The following is the code

Process p = Runtime.getRuntime().exec("cmd /c start CPrun.bat");
p.waitFor();

CRun.bat is the name of the batch file.

The following is the error on cmd

'gcc' is not recognized as an internal or external command, 
operable program or batch file.

Note that gcc is my Compiler for C which is defined in the path of my Computer

Answer 1

Specifying the full path should do the trick. But don't forget to surround it with double quotes " . In batch it is recommended to surround all your paths with double quotes because in windows paths are very likely to contain whitespaces. Without the double quotes the whitespace will be handled as a delimiter, braking your paths in distinct parts (as if they were different arguments/executables).

About the environment variables: you will only have access to the environment variables your system passed to your JVM. To see these variables you can use System.getenv() it returns a string to string map, mapping environment variable names on their value. I have made a little demo where all available environment variables are printed.