// 译者注：enum 在 Java 5.0 中是关键字，所以该例在 5.0 中应该编译失败
// 但英文原著发表于 Java 5.0 出现之前，所以可以使用 enum 作变量名
// 为忠于原著，这里未作修改
Enumeration enum = jarFile.entries();
while (enum.hasMoreElements()) {
  process(enum.nextElement());
}

import java.io.*;
import java.util.*;
import java.util.jar.*;
public class JarDir {
  public static void main (String args[]) 
    throws IOException {
    if (args.length != 1) {
      System.out.println("Please provide a JAR filename");
      System.exit(-1);
    }
    JarFile jarFile = new JarFile(args[0]);
    Enumeration enum = jarFile.entries();
    while (enum.hasMoreElements()) {
      process(enum.nextElement());
    }
  }
  private static void process(Object obj) {
    JarEntry entry = (JarEntry)obj;
    String name = entry.getName();
    long size = entry.getSize();
    long compressedSize = entry.getCompressedSize();
    System.out.println(name + " " + size + " " + compressedSize);
  }
}

META-INF/MANIFEST.MF  5315  1910
META-INF/4JCEJARS.SF  5368  1958
META-INF/4JCEJARS.DSA  2207  1503
META-INF/    0    2
javax/ 0    0
javax/crypto/  0    0
javax/crypto/interfaces/    0    0
javax/crypto/interfaces/DHKey.class   209   185
javax/crypto/interfaces/DHPublicKey.class    265   215
javax/crypto/interfaces/DHPrivateKey.class   267   215
javax/crypto/interfaces/PBEKey.class  268   224
javax/crypto/SecretKey.class  167   155
...

import java.io.*;
import java.util.jar.*;
public class JarRead {
  public static void main (String args[]) 
    throws IOException {
    if (args.length != 2) {
      System.out.println("Please provide a JAR filename and file to read");
      System.exit(-1);
    }
    JarFile jarFile = new JarFile(args[0]);
    JarEntry entry = jarFile.getJarEntry(args[1]);
    InputStream input = jarFile.getInputStream(entry);
    process(input);
    jarFile.close();
  }
  private static void process(InputStream input) 
    throws IOException {
    InputStreamReader isr = 
      new InputStreamReader(input);
    BufferedReader reader = new BufferedReader(isr);
    String line;
    while ((line = reader.readLine()) != null) {
      System.out.println(line);
    }
    reader.close();
  }
}

The itsy bitsy spider 
Ran up the water spout
Down came the rain and
Washed the spider out