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ImageReader 读取jpeg出错,该如何解决

热度:76   发布时间:2016-04-24 12:26:49.0
ImageReader 读取jpeg出错
下面是书上的例子,为什么运行时出错:
Not a JPEG file: starts with 0x00 0x00
jpg文件可以正常打开的呀?


package ch03.image;

import java.awt.Image;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;

public class SkiImageClient2 {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
  SkiImageClient2 sc2=new SkiImageClient2();
   
sc2.createImage("telemk");
//sc2.getRawBytes("nordic");
}


public byte[] getRawBytes(String name)
{
System.out.println("Start....");
ByteArrayOutputStream out=new ByteArrayOutputStream();
try
{
String cwd=System.getProperty("user.dir");
String sep=System.getProperty("file.separator");
String base_name=cwd+sep+"jpegs"+sep;
String file_name=base_name+name+".jpg";

FileInputStream in=new FileInputStream(file_name);

if(in==null)

{
System.out.println("in is null");
in=new FileInputStream(base_name+"nordic.jpg");
}

byte[] buffer=new byte[2048];
int n=0;
 
while ((n=in.read())!=-1)
out.write(buffer,0,n);
 
 
in.close();
System.out.println("End....");
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
return out.toByteArray();

}

public Image createImage(String name)
{
byte[] bytes=getRawBytes(name);
ByteArrayInputStream in=new ByteArrayInputStream(bytes);

Iterator iterators=ImageIO.getImageReadersByFormatName("jpg");
ImageReader iterator=(ImageReader)iterators.next();
 
try
{
ImageInputStream iis=ImageIO.createImageInputStream(in);
iterator.setInput(iis,true);
return iterator.read(0);

}
catch(IOException e)
{
System.out.println("Error");
System.err.print(e.getMessage());
return null;
}
 
//return null;
 
}

}


------解决方案--------------------
探讨
Java code

while ((n = in.read()) != -1)




Java code

while ((n = in.read(buffer)) != -1)


上面改成下面这句,应该OK了
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