如何从Net Beans中的Java代码执行jar文件

Question

I have a JAR file("AccessDB.jar" - on executing it, launches a tool). I have to access this jar file from this location (D:\\NB\\ProjFolder) in Netbeans 7.0. I tried reading it using ProcessBuilder, but it failed.

From this java code, I have to launch the tool (in jar file) by reading it. How can the code be modified for this?

public class classAccessDB {

public void GenerateAccessDB() {
    Runtime run = Runtime.getRuntime(); 
try 
{
     ProcessBuilder pb = new ProcessBuilder("C:\\Program Files\\Java\\jdk1.6.0_20\\bin\\java.exe", "-jar", "AccessDB.jar");
     pb.directory(new File("D:\\NB\\ProjFolder")); 
     Process p = pb.start(); 
     InputStream is = p.getInputStream(); 
     BufferedReader br = new BufferedReader(new InputStreamReader(is)); 

     String resultOutput = br.toString(); 
     System.out.println(resultOutput); 
}
catch(Exception E) 
{
     E.printStackTrace();
     System.out.println(E.getMessage());   
}
}
}

Answer 1

Might be possible your .jar isn't executable. Instantiate classes or make call to any static method.

Add Main-Class entry while creating a JAR. into manifest file .

Then you can use

Process ps=Runtime.getRuntime().exec(new String[]{"java","-jar","yourJar.jar"});
        ps.waitFor();
        java.io.InputStream is=ps.getInputStream();
        byte b[]=new byte[is.available()];
        is.read(b,0,b.length);
        System.out.println(new String(b));

Answer 2

Well it worked for me when I did :

public class classAccessDB {

public void GenerateAccessDB() {
Runtime run = Runtime.getRuntime(); 
try 
{
 ProcessBuilder pb = new ProcessBuilder("\"C:\\Program Files\\Java\\jdk1.6.0_20\\bin\\java\" -jar \"D:\\NB\\ProjFolder\\AccessDB.jar\"");

 Process p = pb.start(); 
 InputStream is = p.getInputStream(); 
 BufferedReader br = new BufferedReader(new InputStreamReader(is)); 

 String resultOutput = br.toString(); 
 System.out.println(resultOutput); 
}
catch(Exception E) 
{
  E.printStackTrace();
  System.out.println(E.getMessage());   
}
}
}

By the way your question helped me a lot thx :))

Answer 3

Try

ProcessBuilder pb = new ProcessBuilder(
    "C:\\Program Files\\Java\\jdk1.6.0_20\\bin\\java.exe",
    "-jar",
    "D:\\NB\\ProjFolder\\AccessDB.jar");

instead. I saw in your code that you do change to the folder D:\\NB\\ProjFolder before starting the Java process and I would also think that should work. But using the absolute file name will work for sure.

If that doesn't work, look at the error message which you get; that should contain a clue what is wrong.