Java Tips Blog

import java.io.BufferedReader;
 
import java.io.File;
 
import java.io.FileInputStream;
 
import java.io.FileOutputStream;
 
import java.io.IOException;
 
import java.io.InputStream;
 
import java.io.InputStreamReader;
 
import java.util.Enumeration;
 
import java.util.jar.JarEntry;
 
import java.util.jar.JarFile;
 
import java.util.jar.JarOutputStream;   public class EditJarFile {
 
public static void main(String args[]) {
 
 if (args.length != 2) {
 
    System.err.println("command: java EditJarFile sample.jar addsample.txt");
 
    System.exit(-1);
 
}
 
String jartoEdit = args[0];
 
String newFile = args[1];
 
File tempJar = null;
 
try {
 
  tempJar = File.createTempFile(jartoEdit, null);
 
} catch (IOException e) {
 
  System.err.println("Unable to create intermediate file.");
 
  System.exit(-2);
 
}
 
  JarFile jar = null;
 
try {
 
   jar = new JarFile(jartoEdit);
 
} catch (IOException e) {
 
   System.err.println("Unable to access original file.");
 
   System.exit(-3);
 
}
 
boolean delFlag = false;
 
try {
 
JarOutputStream newJar =
 
new JarOutputStream(
 
new FileOutputStream(tempJar));
 
byte buffer[] = new byte[1024];
 
int bytesRead;
 
try {
 
FileInputStream fis = new FileInputStream(newFile);
 
Enumeration entries = jar.entries();
 
while (entries.hasMoreElements()) {
 
JarEntry entry = (JarEntry) entries.nextElement();
 
String name = entry.getName();
 
System.out.println
 
("Copy " + name + " into new jar? (y or n)");
 
BufferedReader reader =
 
new BufferedReader
 
(new InputStreamReader(System.in));
 
String line = reader.readLine();
 
if ("n".equals(line)) {
 
System.out.println("Skipping: " + name);
 
continue;
 
}
 
InputStream is = jar.getInputStream(entry);
 
newJar.putNextEntry(entry);
 
while ((bytesRead = is.read(buffer)) != -1) {
 
newJar.write(buffer, 0, bytesRead);
 
}
 
}
 
try {
 
JarEntry entry = new JarEntry(newFile);
 
newJar.putNextEntry(entry);
 
while ((bytesRead = fis.read(buffer)) != -1) {
 
newJar.write(buffer, 0, bytesRead);
 
}
 
} finally {
 
fis.close();
 
}
 
delFlag = true;
 
} catch (IOException ex) {
 
System.err.println
 
("Operation aborted due to : " + ex);
 
} finally {
 
try {
 
newJar.close();
 
} catch (IOException ignored) {
 
}
 
}
 
} catch (IOException ex) {
 
System.err.println(
 
"Can't access new file");
 
} finally {
 
try {
 
jar.close();
 
} catch (IOException ignored) {
 
}
 
if (!delFlag) {
 
tempJar.delete();
 
}
 
}
 
if (delFlag) {
 
File origFile = new File(jartoEdit);
 
origFile.delete();
 
tempJar.renameTo(origFile);
 
}
 
}
 
}