把你的程序编译了一下,发现可以读图片,看半天也没找到什么错误,后来看到楼主读的是bmp图像,于是试着读了一个bmp图像,反先也不行,于是认为ImageIO.read读不了bmp格式的矢量图。楼主可以自己搜索一下:java bmp
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// This code was taken and cleaned up from a
// Javaworld tips and tricks column
//
import java.awt.image.*;
import java.awt.*;
import java.io.*;
import javax.swing.*; //
// really just a collection of methods to read a BMP file
//
public class BMPLoader
{ // build an int from a byte array - convert little to big endian
public static int constructInt(byte[] in,int offset) {
int ret = ((int)in[offset + 3] & 0xff);
ret = (ret << 8) | ((int)in[offset + 2] & 0xff);
ret = (ret << 8) | ((int)in[offset + 1] & 0xff);
ret = (ret << 8) | ((int)in[offset + 0] & 0xff);
return(ret);
}
// build an int from a byte array - convert little to big endian
// set high order bytes to 0xfff
public static int constructInt3(byte[] in,int offset) {
int ret = 0xff;
ret = (ret << 8) | ((int)in[offset + 2] & 0xff);
ret = (ret << 8) | ((int)in[offset + 1] & 0xff);
ret = (ret << 8) | ((int)in[offset + 0] & 0xff);
return(ret);
} // build an int from a byte array - convert little to big endian
public static long constructLong(byte[] in,int offset) {
long ret = ((long)in[offset + 7] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 6] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 5] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 4] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 3] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 2] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 1] & 0xff);
ret |= (ret << 8) | ((long)in[offset + 0] & 0xff);
return(ret);
}
// build an double from a byte array - convert little to big endian
public static double constructDouble(byte[] in,int offset) {
long ret = constructLong(in,offset);
return(Double.longBitsToDouble(ret));
} // build an short from a byte array - convert little to big endian
public static short constructShort(byte[] in,int offset) {
short ret = (short)((short)in[offset + 1] & 0xff);
ret = (short)((ret << 8) | (short)((short)in[offset + 0] & 0xff));
return(ret);
} //
// internal class representing a bitmap header structure
// with code to read it from a file
static class BitmapHeader {
public int nsize;
public int nbisize;
public int nwidth;
public int nheight;
public int nplanes;
public int nbitcount;
public int ncompression;
public int nsizeimage;
public int nxpm;
public int nypm;
public int nclrused;
public int nclrimp; // read in the bitmap header
public void read(FileInputStream fs) throws IOException
{
final int bflen=14; // 14 byte BITMAPFILEHEADER
byte bf[]=new byte[bflen];
fs.read(bf,0,bflen);
final int bilen=40; // 40-byte BITMAPINFOHEADER
byte bi[]=new byte[bilen];
fs.read(bi,0,bilen); // Interperet data.
nsize = constructInt(bf,2);
// System.out.println("File type is :"+(char)bf[0]+(char)bf[1]);
// System.out.println("Size of file is :"+nsize); nbisize = constructInt(bi,2);
// System.out.println("Size of bitmapinfoheader is :"+nbisize); nwidth = constructInt(bi,4);
// System.out.println("Width is :"+nwidth); nheight = constructInt(bi,8);
// System.out.println("Height is :"+nheight); nplanes = constructShort(bi,12); //(((int)bi[13]&0xff)<<8) | (int)bi[12]&0xff;
// System.out.println("Planes is :"+nplanes); nbitcount = constructShort(bi,14); //(((int)bi[15]&0xff)<<8) | (int)bi[14]&0xff;
// System.out.println("BitCount is :"+nbitcount); // Look for non-zero values to indicate compression
ncompression = constructInt(bi,16);
// System.out.println("Compression is :"+ncompression); nsizeimage = constructInt(bi,20);
// System.out.println("SizeImage is :"+nsizeimage); nxpm = constructInt(bi,24);
// System.out.println("X-Pixels per meter is :"+nxpm); nypm = constructInt(bi,28);
// System.out.println("Y-Pixels per meter is :"+nypm); nclrused = constructInt(bi,32);
// System.out.println("Colors used are :"+nclrused); nclrimp = constructInt(bi,36);
// System.out.println("Colors important are :"+nclrimp);
}
}
{
try {
BitmapHeader bh = new BitmapHeader();
bh.read(fs); if (bh.nbitcount==24)
return(readMap24(fs,bh)); if (bh.nbitcount==32)
return(readMap32(fs,bh)); if (bh.nbitcount==8)
return(readMap8(fs,bh)); fs.close();
}
catch (IOException e)
{
// System.out.println("Caught exception in loadbitmap!");
}
return(null);
}
/**
readMap24 internal routine to read the bytes in a 24 bit bitmap Arguments:
fs - file stream
bh - header struct
Returns:
Image Object, be sure to check for (Image)null !!!! */ protected static Image readMap32(FileInputStream fs,BitmapHeader bh) throws IOException
{
Image image;
// No Palatte data for 24-bit format but scan lines are
// padded out to even 4-byte boundaries.
int xwidth = bh.nsizeimage / bh.nheight;
int ndata[] = new int [bh.nheight * bh.nwidth];
byte brgb[] = new byte [ bh.nwidth * 4 * bh.nheight];
fs.read (brgb, 0, bh.nwidth * 4 * bh.nheight);
int nindex = 0;
for (int j = 0; j < bh.nheight; j++)
{
for (int i = 0; i < bh.nwidth; i++)
{
ndata [bh.nwidth * (bh.nheight - j - 1) + i] = constructInt3(brgb,nindex);
nindex += 4;
}
} image = Toolkit.getDefaultToolkit().createImage
( new MemoryImageSource (bh.nwidth, bh.nheight,
ndata, 0, bh.nwidth));
fs.close();
return(image);
} /**
readMap24 internal routine to read the bytes in a 24 bit bitmap Arguments:
fs - file stream
bh - header struct
Returns:
Image Object, be sure to check for (Image)null !!!! */ protected static Image readMap24(FileInputStream fs,BitmapHeader bh) throws IOException
{
Image image;
// No Palatte data for 24-bit format but scan lines are
// padded out to even 4-byte boundaries.
int npad = (bh.nsizeimage / bh.nheight) - bh.nwidth * 3;
int ndata[] = new int [bh.nheight * bh.nwidth];
byte brgb[] = new byte [( bh.nwidth + npad) * 3 * bh.nheight];
fs.read (brgb, 0, (bh.nwidth + npad) * 3 * bh.nheight);
int nindex = 0;
for (int j = 0; j < bh.nheight; j++)
{
for (int i = 0; i < bh.nwidth; i++)
{
ndata [bh.nwidth * (bh.nheight - j - 1) + i] = constructInt3(brgb,nindex);
nindex += 3;
}
nindex += npad;
} image = Toolkit.getDefaultToolkit().createImage
( new MemoryImageSource (bh.nwidth, bh.nheight,
ndata, 0, bh.nwidth));
fs.close();
return(image);
}
/**
readMap8 internal routine to read the bytes in a 8 bit bitmap Arguments:
fs - file stream
bh - header struct
Returns:
Image Object, be sure to check for (Image)null !!!! */
protected static Image readMap8(FileInputStream fs,BitmapHeader bh) throws IOException
{
Image image; // Have to determine the number of colors, the clrsused
// parameter is dominant if it is greater than zero. If
// zero, calculate colors based on bitsperpixel.
int nNumColors = 0;
if (bh.nclrused > 0)
{
nNumColors = bh.nclrused;
}
else
{
nNumColors = (1&0xff)<< bh.nbitcount;
}
// System.out.println("The number of Colors is"+nNumColors); // Some bitmaps do not have the sizeimage field calculated
// Ferret out these cases and fix 'em.
if (bh.nsizeimage == 0)
{
bh.nsizeimage = ((((bh.nwidth* bh.nbitcount)+31) & ~31 ) >> 3);
bh.nsizeimage *= bh.nheight;
// System.out.println("nsizeimage (backup) is"+nsizeimage);
} // Read the palatte colors.
int npalette[] = new int [nNumColors];
byte bpalette[] = new byte [nNumColors*4];
fs.read (bpalette, 0, nNumColors*4);
int nindex8 = 0;
for (int n = 0; n < nNumColors; n++)
{
npalette[n] = constructInt3(bpalette,nindex8);
nindex8 += 4;
} // Read the image data (actually indices into the palette)
// Scan lines are still padded out to even 4-byte
// boundaries.
int npad8 = (bh.nsizeimage / bh.nheight) - bh.nwidth;
// System.out.println("nPad is:"+npad8); int ndata8[] = new int [bh.nwidth * bh.nheight];
byte bdata[] = new byte [(bh.nwidth+npad8)* bh.nheight];
fs.read (bdata, 0, (bh.nwidth+npad8)*bh.nheight);
nindex8 = 0;
for (int j8 = 0; j8 < bh.nheight; j8++)
{
for (int i8 = 0; i8 < bh.nwidth; i8++)
{
ndata8 [bh.nwidth*(bh.nheight-j8-1)+i8] =
npalette [((int)bdata[nindex8]&0xff)];
nindex8++;
}
nindex8 += npad8;
} image = Toolkit.getDefaultToolkit().createImage
( new MemoryImageSource (bh.nwidth, bh.nheight,
ndata8, 0, bh.nwidth)); return(image);
} /**
load method - see read for details Arguments:
sdir and sfile are the result of the FileDialog()
getDirectory() and getFile() methods. Returns:
Image Object, be sure to check for (Image)null !!!! */
public static Image load(String sdir, String sfile) {
return(load(sdir + sfile));
}
/**
load method - see read for details Arguments:
sdir - full path name Returns:
Image Object, be sure to check for (Image)null !!!! */
public static Image load(String sdir)
{
try
{
FileInputStream fs=new FileInputStream(sdir);
return(read(fs));
}
catch(IOException ex) {
return(null);
}
} public static void main(String[] args) throws IOException
{
if(args.length == 0){
System.out.println("Usage >java BMPLoader ImageFile.bmp");
System.exit(0);
}
FileInputStream in = new FileInputStream(args[0]);
Image TheImage = read(in);
JFrame TheFrame = new JFrame(args[0]);
JLabel TheLabel = new JLabel(new ImageIcon(TheImage));
TheFrame.getContentPane().add(new JScrollPane(TheLabel));
TheFrame.setSize(300,300);
TheFrame.setVisible(true);
}
// end class BMPLoader
}