Java runtime exec not handling string array well

Question

I have a tomcat servlet which calls a jar function with parameters. The first parameter sometimes contains space. So I tried to use a String array, but it doesn't work at all.

What am I doing wrong?

requestParm = "java -classpath c:\\j\\test.jar test.connect " + fileName + " new";
requestParmarray =new String[]{"java -classpath c:\\j\\test.jar test.connect ",fileName , " new"};
requestParmarrayNew =new String[]{"java -classpath c:\\j\\test.jar test.connect "+fileName+" new"};

// This line works.but can not handle space well
Process ls_proc = Runtime.getRuntime().exec(requestPar);

// Does not call the function at all
Process ls_proc = Runtime.getRuntime().exec(requestParmarray ); 

// Does not call the function at all
Process ls_proc = Runtime.getRuntime().exec(requestParmarrayNew ); 

// Does not call the function at all
Process ls_proc = new ProcessBuilder("java -classpath c:\\j\\test.jar test.connect ",fileName, "new" ).start();

T.J. Crowder · Accepted Answer · 2016-06-21 05:42:43Z

5

You're creating the array incorrectly: Each individual argument must be in its own entry:

String[] requestParmArray = new String[] {
    "java",
    "-classpath",
    "c:\\j\\test.jar",
    "test.connect",
    fileName,
    "new"
};
Process ls_proc = Runtime.getRuntime().exec(requestParmArray);

Also note that I removed the space you had after test.connect; the spaces you put on the command line are just to separate arguments, but in the above, they're separated by being separate entries in the array.

edited Jun 21, 2016 at 5:42

answered Jun 21, 2016 at 5:39

T.J. Crowder

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1 Comment

Andy Shao Over a year ago

This fixes my problem :). Thank you.

Krzysztof Krasoń · Accepted Answer · 2016-06-21 05:44:11Z

2

You should make the array in exec() have each parameter as a separate array entry like:

String[] requestPar = new String[]{"java", "-classpath", "c:\\j\\test.jar", "test.connect ", fileName, "new"};

And use it:

Process ls_proc = Runtime.getRuntime().exec(requestPar);

edited Jun 21, 2016 at 5:44

answered Jun 21, 2016 at 5:39

Krzysztof Krasoń

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1 Comment

Andy Shao Over a year ago

This fixes my problem. Thank you.

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