java编程思想—chapter11.Zipcompress.java

//: c12:ZipCompress.java
// Uses Zip compression to compress any
// number of files given on the command line.
// {Args: ZipCompress.java}
// {Clean: test.zip}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import com.bruceeckel.simpletest.*;
import java.io.*;
import java.util.*;
import java.util.zip.*;

public class ZipCompress {
  private static Test monitor = new Test();
  // Throw exceptions to console:
  public static void main(String[] args)
  throws IOException {
    FileOutputStream f = new FileOutputStream("test.zip");
    CheckedOutputStream csum =
      new CheckedOutputStream(f, new Adler32());
     ZipOutputStream zos = new ZipOutputStream(csum);
     BufferedOutputStream out =
      new BufferedOutputStream(zos);
    zos.setComment("A test of Java Zipping");
    // No corresponding getComment(), though.
    for(int i = 0; i < args.length; i++) {
      System.out.println("Writing file " + args[i]);
      BufferedReader in =
        new BufferedReader(new FileReader(args[i]));
      zos.putNextEntry(new ZipEntry(args[i]));
      int c;
      while((c = in.read()) != -1)
        out.write(c);
      in.close();
    }
    out.close();
    // Checksum valid only after the file has been closed!
    System.out.println("Checksum: " +
      csum.getChecksum().getValue());
    // Now extract the files:
    System.out.println("Reading file");
    FileInputStream fi = new FileInputStream("test.zip");
    CheckedInputStream csumi =
      new CheckedInputStream(fi, new Adler32());
    ZipInputStream in2 = new ZipInputStream(csumi);
    BufferedInputStream bis = new BufferedInputStream(in2);
    ZipEntry ze;
    while((ze = in2.getNextEntry()) != null) {
      System.out.println("Reading file " + ze);
      int x;
      while((x = bis.read()) != -1)
        System.out.write(x);
    }
    if(args.length == 1)
      monitor.expect(new String[] {
        "Writing file " + args[0],
        "%% Checksum: //d+",
        "Reading file",
        "Reading file " + args[0]}, args[0]);
    System.out.println("Checksum: " +
      csumi.getChecksum().getValue());
    bis.close();
    // Alternative way to open and read zip files:
    ZipFile zf = new ZipFile("test.zip");
    Enumeration e = zf.entries();
    while(e.hasMoreElements()) {
      ZipEntry ze2 = (ZipEntry)e.nextElement();
      System.out.println("File: " + ze2);
      // ... and extract the data as before
    }
    if(args.length == 1)
      monitor.expect(new String[] {
        "%% Checksum: //d+",
        "File: " + args[0]
      });
  }
} ///:~ 

/*为什么运行会出现错误，如下：

Exception in thread "main" java.util.zip.ZipException: ZIP file must have at least one entry
 at java.util.zip.ZipOutputStream.finish(ZipOutputStream.java:291)
 at java.util.zip.DeflaterOutputStream.close(DeflaterOutputStream.java:141)
 at java.util.zip.ZipOutputStream.close(ZipOutputStream.java:310)
 at java.io.FilterOutputStream.close(FilterOutputStream.java:143)
 at ch11.ZipCopress.main(ZipCopress.java:25)

请朋友们帮忙分析下，谢谢

*/