Java编程100例

/* * @(#)CNZipOutputStream.java 1.27 03/02/07 * * Copyright 2003 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package java.util.zip; import java.io.OutputStream; import java.io.IOException; import java.util.Vector; import java.util.Hashtable; import java.util.Enumeration; /** * This class implements an output stream filter for writing files in the * ZIP file format. Includes support for both compressed and uncompressed * entries. * * @author David Connelly * @version 1.27, 02/07/03 */ public class CNZipOutputStream extends DeflaterOutputStream implements ZipConstants { private ZipEntry entry; private Vector entries = new Vector(); private Hashtable names = new Hashtable(); private CRC32 crc = new CRC32(); private long written; private long locoff = 0; private String comment; private int method = DEFLATED; private boolean finished; private String encoding="UTF-8"; private boolean closed = false; /** * Check to make sure that this stream has not been closed */ private void ensureOpen() throws IOException { if (closed) { throw new IOException("Stream closed"); } } /** * Compression method for uncompressed (STORED) entries. */ public static final int STORED = ZipEntry.STORED; /** * Compression method for compressed (DEFLATED) entries. */ public static final int DEFLATED = ZipEntry.DEFLATED; /** * Creates a new ZIP output stream. * @param out the actual output stream */ public CNZipOutputStream(OutputStream out) { super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true)); usesDefaultDeflater = true; } public CNZipOutputStream(OutputStream out,String encoding) { super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true)); usesDefaultDeflater = true; this.encoding=encoding; } /** * Sets the ZIP file comment. * @param comment the comment string * @exception IllegalArgumentException if the length of the specified * ZIP file comment is greater than 0xFFFF bytes */ public void setComment(String comment) { if (comment != null && comment.length() > 0xffff/3 && getUTF8Length(comment) > 0xffff) { throw new IllegalArgumentException("ZIP file comment too long."); } this.comment = comment; } /** * Sets the default compression method for subsequent entries. This * default will be used whenever the compression method is not specified * for an individual ZIP file entry, and is initially set to DEFLATED. * @param method the default compression method * @exception IllegalArgumentException if the specified compression method * is invalid */ public void setMethod(int method) { if (method != DEFLATED && method != STORED) { throw new IllegalArgumentException("invalid compression method"); } this.method = method; } /** * Sets the compression level for subsequent entries which are DEFLATED. * The default setting is DEFAULT_COMPRESSION. * @param level the compression level (0-9) * @exception IllegalArgumentException if the compression level is invalid */ public void setLevel(int level) { def.setLevel(level); } /** * Begins writing a new ZIP file entry and positions the stream to the * start of the entry data. Closes the current entry if still active. * The default compression method will be used if no compression method * was specified for the entry, and the current time will be used if * the entry has no set modification time. * @param e the ZIP entry to be written * @exception ZipException if a ZIP format error has occurred * @exception IOException if an I/O error has occurred */ public void putNextEntry(ZipEntry e) throws IOException { ensureOpen(); if (entry != null) { closeEntry(); // close previous entry } if (e.time == -1) { e.setTime(System.currentTimeMillis()); } if (e.method == -1) { e.method = method; // use default method } switch (e.method) { case DEFLATED: if (e.size == -1 || e.csize == -1 || e.crc == -1) { // store size, compressed size, and crc-32 in data descriptor // immediately following the compressed entry data e.flag = 8; } else if (e.size != -1 && e.csize != -1 && e.crc != -1) { // store size, compressed size, and crc-32 in LOC header e.flag = 0; } else { throw new ZipException( "DEFLATED entry missing size, compressed size, or crc-32"); } e.version = 20; break; case STORED: // compressed size, uncompressed size, and crc-32 must all be // set for entries using STORED compression method if (e.size == -1) { e.size = e.csize; } else if (e.csize == -1) { e.csize = e.size; } else if (e.size != e.csize) { throw new ZipException( "STORED entry where compressed != uncompressed size"); } if (e.size == -1 || e.crc == -1) { throw new ZipException( "STORED entry missing size, compressed size, or crc-32"); } e.version = 10; e.flag = 0; break; default: throw new ZipException("unsupported compression method"); } e.offset = written; if (names.put(e.name, e) != null) { throw new ZipException("duplicate entry: " + e.name); } writeLOC(e); entries.addElement(e); entry = e; } /** * Closes the current ZIP entry and positions the stream for writing * the next entry. * @exception ZipException if a ZIP format error has occurred * @exception IOException if an I/O error has occurred */ public void closeEntry() throws IOException { ensureOpen(); ZipEntry e = entry; if (e != null) { switch (e.method) { case DEFLATED: def.finish(); while (!def.finished()) { deflate(); } if ((e.flag & 8) == 0) { // verify size, compressed size, and crc-32 settings if (e.size != def.getTotalIn()) { throw new ZipException( "invalid entry size (expected " + e.size + " but got " + def.getTotalIn() + " bytes)"); } if (e.csize != def.getTotalOut()) { throw new ZipException( "invalid entry compressed size (expected " + e.csize + " but got " + def.getTotalOut() + " bytes)"); } if (e.crc != crc.getValue()) { throw new ZipException( "invalid entry CRC-32 (expected 0x" + Long.toHexString(e.crc) + " but got 0x" + Long.toHexString(crc.getValue()) + ")"); } } else { e.size = def.getTotalIn(); e.csize = def.getTotalOut(); e.crc = crc.getValue(); writeEXT(e); } def.reset(); written += e.csize; break; case STORED: // we already know that both e.size and e.csize are the same if (e.size != written - locoff) { throw new ZipException( "invalid entry size (expected " + e.size + " but got " + (written - locoff) + " bytes)"); } if (e.crc != crc.getValue()) { throw new ZipException( "invalid entry crc-32 (expected 0x" + Long.toHexString(e.crc) + " but got 0x" + Long.toHexString(crc.getValue()) + ")"); } break; default: throw new InternalError("invalid compression method"); } crc.reset(); entry = null; } } /** * Writes an array of bytes to the current ZIP entry data. This method * will block until all the bytes are written. * @param b the data to be written * @param off the start offset in the data * @param len the number of bytes that are written * @exception ZipException if a ZIP file