Java IO Tutorial - Java JarFile.getEntry(String name)

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Syntax

JarFile.getEntry(String name) has the following syntax.

public ZipEntry getEntry(String name)

Example

In the following code shows how to use JarFile.getEntry(String name) method.

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.util.zip.ZipFile;
//ww  w  .  j  ava  2 s.  co  m
/**
 * This program will search all jar and zip files in the current directory for a
 * given class file.
 * 
 * @author Dave Glasser
 */
public class Main {

  /**
   * Returns true if the jar or zip file at jarFilePath contains (with the
   * internal path) the file named by classFilePath.
   */
  public static boolean searchJarFile(String jarFilePath, String classFilePath) {
    return searchJarFile(new File(jarFilePath), classFilePath);
  }

  public static boolean searchJarFile(File file, String classFilePath) {

    try {
      if (!file.exists())
        return false;

      ZipFile jarFile = new ZipFile(file);
      if (jarFile.getEntry(classFilePath) != null) {
        jarFile.close();
        return true;
      } else {
        jarFile.close();
        return false;
      }
    } catch (IOException ex) {
      System.out.println(ex.toString());
      return false;
    }
  }

  static class ArchiveFilter implements FileFilter {

    public boolean accept(File pathName) {
      String upcase = pathName.getName().toUpperCase();
      if (upcase.endsWith(".ZIP") || upcase.endsWith(".JAR"))
        return true;
      return false;
    }
  }

  public static void main(String[] args) {
    if (args.length == 0) {
      System.out.println("usage: java ClassFinder <class name>\n\n"
          + "example: java ClassFinder java.lang.String\n");
      System.exit(0);
    }

    File cwd = new File(".");
    File[] archives = cwd.listFiles(new ArchiveFilter());

    String classFileName = args[0].replace('.', '/');
    if (classFileName.endsWith(".class") == false) {
      classFileName += ".class";
    }

    System.out.println("Searching for " + classFileName + " ...");
    for (int j = 0; j < archives.length; j++) {
      // System.out.println("Searching " + archives[j].getName());
      if (searchJarFile(archives[j], classFileName)) {
        System.out.println("FOUND IN " + archives[j].getName());
      }
    }
  }
}

The code above generates the following result.

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