java解压zip异常_java解压zip文件示例
若是使用Java自帶的壓縮工具包來實現解壓縮文件到指定文件夾的功能，因為jdk提供的zip只能按UTF-8格式處理，而Windows系統中文件名是以GBK方式編碼的，所以如果是解壓一個包含中文文件名的zip包，會報非法參數異常，所以要實現解壓縮，就得對DeflaterOutputStream.java、InflaterInputStream.java、ZipConstants.java、ZipEntry.java、ZipInputStream.java以及ZipOutputStream.java這些相關的類進行修改，過程如下：
因為從 J2SE 1.4 開始，Java 編譯器不再支持 import 進未命包名的類、接口，所以在創建的Java項目中，一定要新建一個自己定義的包，包命名的格式一般為學校域名的逆序+自己的網名，比如cn.edu.xidian.crytoll。
在包內新建DeflaterOutputStream類，代碼如下：
DeflaterOutputStream.java:
package cn.edu.xdian.crytoll;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.Deflater;
/**
* This class implements an output stream filter for compressing data in
* the "deflate" compression format. It is also used as the basis for other
* types of compression filters, such as GZIPOutputStream.
*
* @see???? Deflater
* @version???? 1.36, 03/13/06
* @author? David Connelly
*/
public
class DeflaterOutputStream extends FilterOutputStream {
/**
* Compressor for this stream.
*/
protected Deflater def;
/**
* Output buffer for writing compressed data.
*/
protected byte[] buf;
/**
* Indicates that the stream has been closed.
*/
private boolean closed = false;
/**
* Creates a new output stream with the specified compressor and
* buffer size.
* @param out the output stream
* @param def the compressor ("deflater")
* @param size the output buffer size
* @exception IllegalArgumentException if size is <= 0
*/
public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
super(out);
if (out == null || def == null) {
throw new NullPointerException();
} else if (size <= 0) {
throw new IllegalArgumentException("buffer size <= 0");
}
this.def = def;
buf = new byte[size];
}
/**
* Creates a new output stream with the specified compressor and
* a default buffer size.
* @param out the output stream
* @param def the compressor ("deflater")
*/
public DeflaterOutputStream(OutputStream out, Deflater def) {
this(out, def, 512);
}
boolean usesDefaultDeflater = false;
/**
* Creates a new output stream with a default compressor and buffer size.
* @param out the output stream
*/
public DeflaterOutputStream(OutputStream out) {
this(out, new Deflater());
usesDefaultDeflater = true;
}
/**
* Writes a byte to the compressed output stream. This method will
* block until the byte can be written.
* @param b the byte to be written
* @exception IOException if an I/O error has occurred
*/
public void write(int b) throws IOException {
byte[] buf = new byte[1];
buf[0] = (byte)(b & 0xff);
write(buf, 0, 1);
}
/**
* Writes an array of bytes to the compressed output stream. This
* method will block until all the bytes are written.
* @param b the data to be written
* @param off the start offset of the data
* @param len the length of the data
* @exception IOException if an I/O error has occurred
*/
public void write(byte[] b, int off, int len) throws IOException {
if (def.finished()) {
throw new IOException("write beyond end of stream");
}
if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
if (!def.finished()) {
// Deflate no more than stride bytes at a time.? This avoids
// excess copying in deflateBytes (see Deflater.c)
int stride = buf.length;
for (int i = 0; i < len; i+= stride) {
def.setInput(b, off + i, Math.min(stride, len - i));
while (!def.needsInput()) {
deflate();
}
}
}
}
/**
* Finishes writing compressed data to the output stream without closing
* the underlying stream. Use this method when applying multiple filters
* in succession to the same output stream.
* @exception IOException if an I/O error has occurred
*/
public void finish() throws IOException {
if (!def.finished()) {
def.finish();
while (!def.finished()) {
deflate();
}
}
}
/**
* Writes remaining compressed data to the output stream and closes the
* underlying stream.
* @exception IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
finish();
if (usesDefaultDeflater)
def.end();
out.close();
closed = true;
}
}
/**
* Writes next block of compressed data to the output stream.
* @throws IOException if an I/O error has occurred
*/
protected void deflate() throws IOException {
int len = def.deflate(buf, 0, buf.length);
if (len > 0) {
out.write(buf, 0, len);
}
}
}
總結
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