Java 如何将zip文件读取为字节数组,然后将字节数组转换回zip文件?
我尝试使用以下代码将ZIP文件转换为字节数组:Java 如何将zip文件读取为字节数组,然后将字节数组转换回zip文件?,java,zip,bytearray,Java,Zip,Bytearray,我尝试使用以下代码将ZIP文件转换为字节数组: private static byte[] readZipFile(String zipFnm) // read in fnm, returning it as a single string { FileInputStream fileInputStream=null; File file = new File(zipFnm); byte[] bFile = new byte[(int) file.length()]; t
private static byte[] readZipFile(String zipFnm)
// read in fnm, returning it as a single string
{
FileInputStream fileInputStream=null;
File file = new File(zipFnm);
byte[] bFile = new byte[(int) file.length()];
try{
//convert file into array of bytes
fileInputStream = new FileInputStream(zipFnm);
fileInputStream.read(bFile);
fileInputStream.close();
}catch(Exception e){
e.printStackTrace();
}
return bFile;
}
public byte[] readXMLFile(){
File file = new File("a.xml");
byte[] b = new byte[(int) file.length()];
try {
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.read(b);
fileInputStream.close();
}catch (FileNotFoundException e) {
System.out.println("File Not Found.");
e.printStackTrace();
}catch (IOException e1) {
System.out.println("Error Reading The File.");
e1.printStackTrace();
}
return b;
}
public void writeXMLFile(byte[] fileContent){
try {
FileOutputStream fos = new FileOutputStream("abc.xml");
fos.write(fileContent);
fos.close();
}catch(FileNotFoundException ex){
System.out.println("FileNotFoundException : " + ex);
}catch(IOException ioe) {
System.out.println("IOException : " + ioe);
}
}
这段代码用于通过调用writeByteToZip(fnm+“.ZIP”)将字节数组转换回ZIP代码>
我做错了什么?我使用
byte[] bzip = readZipFile(zipFnm);
int totalLen1 = bzip.length;
System.out.println("Total byte length of zip: " + totalLen1);
我得到的只是一个零大小的zip文件和Netbeans中的运行时错误,如下所示:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.io.FileOutputStream.write(FileOutputStream.java:305)
at steg.Steg.writeByteToZip(Steg.java:402)
at steg.Steg.save(Steg.java:292)
at steg.frame1.jButton2ActionPerformed(frame1.java:349)
at steg.frame1.access$300(frame1.java:24)
at steg.frame1$4.actionPerformed(frame1.java:172)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2713)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
at java.awt.EventQueue.access$000(EventQueue.java:101)
at java.awt.EventQueue$3.run(EventQueue.java:666)
at java.awt.EventQueue$3.run(EventQueue.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:680)
at java.awt.EventQueue$4.run(EventQueue.java:678)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
由于b文件
为空,将导致您提供的堆栈跟踪
原因可能是readZipFile
方法中的以下行:
byte[] bFile = new byte[(int) file.length()];
在这里,您将分配给局部变量,而不是类字段。尝试将该行替换为:
bFile = new byte[file.length()];
您的代码还显示资源处理能力差。使用现有的库方法进行阅读(例如Java 7)或编写代码,例如:
FileInputStream fileInputStream = null;
try {
fileInputStream = new //...
} finally {
if (fileInputStream != null) {
fileInputStream.close();
}
}
如果您有Java 7,可以使用try with resources:
try (FileInputStream fileInputStream = new FileInputStream(zipFnm)) {
// Use your stream
}
问题可能是writeByteToZip()
中的变量bFile
。确保它不是null
将来,当您发布引发异常的代码时,请在异常发生的行中添加注释(/),正如前面所说的,该文件可能不存在
但是,我只想指出Java 7中可以使用的实用程序。class提供:
static byte[] readAllBytes(Path path)
static Path write(Path path, byte[] bytes, OpenOption... options)
Seams完全符合您的需要。不管文件是否为Zip,您只需简单地获取字节,然后使用它们将其写入其他文件即可。请注意,Java 7中的路径表示所讨论的文件的路径。我没有检查您的代码。但我正在处理此类要求。因此,我想分享我的代码
要读取zip文件并转换为字节数组,请执行以下操作:
private static byte[] readZipFile(String zipFnm)
// read in fnm, returning it as a single string
{
FileInputStream fileInputStream=null;
File file = new File(zipFnm);
byte[] bFile = new byte[(int) file.length()];
try{
//convert file into array of bytes
fileInputStream = new FileInputStream(zipFnm);
fileInputStream.read(bFile);
fileInputStream.close();
}catch(Exception e){
e.printStackTrace();
}
return bFile;
}
public byte[] readXMLFile(){
File file = new File("a.xml");
byte[] b = new byte[(int) file.length()];
try {
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.read(b);
fileInputStream.close();
}catch (FileNotFoundException e) {
System.out.println("File Not Found.");
e.printStackTrace();
}catch (IOException e1) {
System.out.println("Error Reading The File.");
e1.printStackTrace();
}
return b;
}
public void writeXMLFile(byte[] fileContent){
try {
FileOutputStream fos = new FileOutputStream("abc.xml");
fos.write(fileContent);
fos.close();
}catch(FileNotFoundException ex){
System.out.println("FileNotFoundException : " + ex);
}catch(IOException ioe) {
System.out.println("IOException : " + ioe);
}
}
要从字节数组写入zip文件,请执行以下操作:
private static byte[] readZipFile(String zipFnm)
// read in fnm, returning it as a single string
{
FileInputStream fileInputStream=null;
File file = new File(zipFnm);
byte[] bFile = new byte[(int) file.length()];
try{
//convert file into array of bytes
fileInputStream = new FileInputStream(zipFnm);
fileInputStream.read(bFile);
fileInputStream.close();
}catch(Exception e){
e.printStackTrace();
}
return bFile;
}
public byte[] readXMLFile(){
File file = new File("a.xml");
byte[] b = new byte[(int) file.length()];
try {
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.read(b);
fileInputStream.close();
}catch (FileNotFoundException e) {
System.out.println("File Not Found.");
e.printStackTrace();
}catch (IOException e1) {
System.out.println("Error Reading The File.");
e1.printStackTrace();
}
return b;
}
public void writeXMLFile(byte[] fileContent){
try {
FileOutputStream fos = new FileOutputStream("abc.xml");
fos.write(fileContent);
fos.close();
}catch(FileNotFoundException ex){
System.out.println("FileNotFoundException : " + ex);
}catch(IOException ioe) {
System.out.println("IOException : " + ioe);
}
}
希望这有帮助。不是zipFnm
为空-在引用bfile
的行上引发异常。始终在finally块中关闭流。