我从磁盘提供二进制/十六进制数据转储。我被赋予了从中提取图像的任务。它是JPEG，PNG和GIF图像的混合转储。
您可以在此link找到数据文件。
图片页眉和页脚
jpg:
header: FF D8 FF E0 xx xx 4A 46 49 46 00, footer: FF D9
png:
header: 89 50 4E 47 0D 0A 1A 0A, footer: 49 45 4E 44 AE 42 60 82
gif:
header: 47 49 46 38 39 61, footer: 00 3B
完好无损。如何使用Java提取图像？
答案 0 :(得分：0)
我建议你：
FileInputStream打开输入文件。 FileOutputStream，使用图像的正确文件扩展名，然后将内容复制到该文件，直到找到相应的页脚。 答案 1 :(得分：0)
Download Marco Schmidt's jpegextractor的源代码和字节码。
这适用于jpg。
png ，
用
替换copyJpeg函数
private void copypng(InputStream in, OutputStream out) throws
IOException
{
boolean notFinished = true;
long copiedBytes = 3;
do
{
int v1 = in.read();
if (v1 == 0x89) // marker
{
int v2 = in.read();
if (v2 < 0) // end of file
{
out.write(0x82);
copiedBytes++;
notFinished = false;
}
else
if (v2 == 0x49) // embedded png stream ended
{
// copy the end of stream marker
out.write(0x49);
out.write(0x45);
out.write(0x4E);
out.write(0x44);
out.write(0xAE);
out.write(0x42);
out.write(0x60);
out.write(0x82);
copiedBytes += 2;
notFinished = false;
}
else
{
// copy the two bytes, just a marker of the embedded png
out.write(0x89);
out.write(v2);
copiedBytes += 2;
}
}
else
if (v1 == -1) // unexpected end of input file
{
notFinished = false;
}
else // just copy that value
{
out.write(v1);
copiedBytes++;
}
}
while (notFinished);
totalBytes += copiedBytes;
if (!quiet)
{
System.out.println(" (" + copiedBytes + " bytes)");
}
totalOutputFiles++;
// close output stream
try
{
out.close();
}
catch (IOException ioe)
{
// ignore error when closing output stream
}
}
并将process(InputStream in)替换为
private void process(InputStream in) throws
IOException
{
int v1;
do
{
v1 = in.read();
if (v1 == 0x89)
{
int v2 = in.read();
if (v2 == 0x50)
{
int v3 = in.read();
if (v3 == 0x4E)
{
int v4 = in.read();
if (v4 == 0x47)
{
int v5 = in.read();
if (v5 == 0x0D)
{
int v6 = in.read();
if (v6 == 0x0A)
{
int v7 = in.read();
if (v7 == 0x1A)
{
int v8 = in.read();
if (v8 == 0x0A)
{
OutputStream out = createNextOutputStream();
out.write(v1);
out.write(v2);
out.write(v3);
out.write(v4);
out.write(v5);
out.write(v6);
out.write(v7);
out.write(v8);
copypng(in, out);
}
}
}
}
}
}
}
}
}
while (v1 != -1);
}
对于 gif ， 用
替换copyJpeg函数
private void copygif(InputStream in, OutputStream out) throws
IOException
{
boolean notFinished = true;
long copiedBytes = 3;
do
{
int v1 = in.read();
if (v1 == 0x47) // marker
{
int v2 = in.read();
if (v2 < 0) // end of file
{
out.write(0x00);
copiedBytes++;
notFinished = false;
}
else
if (v2 == 0x21) // embedded png stream ended
{
// copy the end of stream marker
out.write(0x21);
out.write(0x00);
out.write(0x00);
out.write(0x3B);
out.write(0x00);
copiedBytes += 2;
notFinished = false;
}
else
{
// copy the two bytes, just a marker of the embedded png
out.write(0x47);
out.write(v2);
copiedBytes += 2;
}
}
else
if (v1 == -1) // unexpected end of input file
{
notFinished = false;
}
else // just copy that value
{
out.write(v1);
copiedBytes++;
}
}
while (notFinished);
totalBytes += copiedBytes;
if (!quiet)
{
System.out.println(" (" + copiedBytes + " bytes)");
}
totalOutputFiles++;
// close output stream
try
{
out.close();
}
catch (IOException ioe)
{
// ignore error when closing output stream
}
}
用
替换process(InputStream in)
private void process(InputStream in) throws
IOException
{
int v1;
do
{
v1 = in.read();
if (v1 == 0x47)
{
int v2 = in.read();
if (v2 == 0x49)
{
int v3 = in.read();
if (v3 == 0x46)
{
int v4 = in.read();
if (v4 == 0x38)
{
int v5 = in.read();
if (v5 == 0x39)
{
int v6 = in.read();
if (v6 == 0x61)
{
OutputStream out = createNextOutputStream();
out.write(v1);
out.write(v2);
out.write(v3);
out.write(v4);
out.write(v5);
out.write(v6);
copygif(in, out);
}
}
}
}
}
}
}
while (v1 != -1);
}
并更新outputSuffix
private void setDefaultArguments()的值