1. 定义文件枚举类
/**
* 文件类型枚举类
*
*/
public enum FileType {
/**
* JEPG.
*/
JPEG("FFD8FF"),
/**
* PNG.
*/
PNG("89504E47"),
/**
* GIF.
*/
GIF("47494638"),
/**
* TIFF.
*/
TIFF("49492A00"),
/**
* TIF.
*/
TIF("49492A00"),
/**
* Windows Bitmap.
*/
BMP("424D"),
/**
* Rich Text Format.
*/
RTF("7B5C727466"),
/**
* XML.
*/
XML("3C3F786D6C"),
/**
* HTML.
*/
HTML("68746D6C3E"),
/**
* Adobe Acrobat.
*/
PDF("255044462D312E"),
/**
* ZIP Archive.
*/
ZIP("504B0304"),
/**
* RAR Archive.
*/
RAR("52617221"),
/**
* Wave.
*/
WAV("57415645"),
/**
* AVI.
*/
AVI("41564920");
private String value = "";
private FileType(String value) {
this.value = value;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
2. 定义文件类型的工具类,来判断文件类型
/**
* 文件类型判断类
*/
public final class FileTypeJudge {
/**
* Constructor
*/
private FileTypeJudge() {}
/**
* 将文件头转换成16进制字符串
*
* @param 原生byte
* @return 16进制字符串
*/
private static String bytesToHexString(byte[] src){
StringBuilder stringBuilder = new StringBuilder();
if (src == null || src.length <= 0) {
return null;
}
for (int i = 0; i < src.length; i++) {
int v = src[i] & 0xFF;
String hv = Integer.toHexString(v);
if (hv.length() < 2) {
stringBuilder.append(0);
}
stringBuilder.append(hv);
}
return stringBuilder.toString();
}
/**
* 得到文件头
*
* @param filePath 文件路径
* @return 文件头
* @throws IOException
*/
private static String getFileContent(String filePath) throws IOException {
byte[] b = new byte[28];
InputStream inputStream = null;
try {
inputStream = new FileInputStream(filePath);
inputStream.read(b, 0, 28);
} catch (IOException e) {
e.printStackTrace();
throw e;
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
throw e;
}
}
}
return bytesToHexString(b);
}
/**
* 判断文件类型
*
* @param filePath 文件路径
* @return 文件类型
*/
public static FileType getType(String filePath) throws IOException {
String fileHead = getFileContent(filePath);
if (fileHead == null || fileHead.length() == 0) {
return null;
}
fileHead = fileHead.toUpperCase();
FileType[] fileTypes = FileType.values();
for (FileType type : fileTypes) {
if (fileHead.startsWith(type.getValue())) {
return type;
}
}
return null;
}
}
3. 在使用jai jar包调用时,先判断类型,再根据具体类型传递具体参数
/***
* 将单个TIF转换为多个JPEG文件
* @param srcFile
* @param destFile
* @return
*/
private static List<String> convertMTifToMJPEG(String srcFile, String destFile) {
List<String> jpegFiles = new ArrayList<String>() ;
try{
FileSeekableStream ss = new FileSeekableStream(srcFile);
TIFFDecodeParam param0 = null;
TIFFEncodeParam param = new TIFFEncodeParam();
JPEGEncodeParam param1 = new JPEGEncodeParam();
FileType fileType = FileTypeJudge.getType(srcFile);
ImageDecoder dec = ImageCodec.createImageDecoder(fileType.toString().toLowerCase(), ss, param0);
int count = dec.getNumPages();
param.setCompression(TIFFEncodeParam.COMPRESSION_GROUP4);
param.setLittleEndian(false);
for (int i = 0; i < count; i++) {
RenderedImage page = dec.decodeAsRenderedImage(i);
File f = new File(destFile + i + DOT + WaterMarkDownloadFileType.JPEG.name().toLowerCase());
ParameterBlock pb = new ParameterBlock();
pb.addSource(page);
pb.add(f.toString());
pb.add(WaterMarkDownloadFileType.JPEG.name());
pb.add(param1);
RenderedOp r = JAI.create("filestore",pb);
r.dispose();
jpegFiles.add(destFile + i + DOT + WaterMarkDownloadFileType.JPEG.name().toLowerCase()) ;
}
} catch (IOException e) {
e.printStackTrace();
}
return jpegFiles;
}
时间： 2024-11-07 00:17:26