Java io Stream operation demo class

1. read operation
/** *@author lxw *@date 2020/6/24 *@desc Get file input stream , Read here into memory *@param [fileName]
*@return byte[] **/ public byte[] readPdfFile(String fileName) throws
Exception{ InputStream in = null; byte[] bytesRel; try {
// read Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH File name bit under path fileName File File f = new
File(Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH+fileName); in = new
FileInputStream(f); //in.available It is only suitable for judging the number of bytes in the stream when reading local files , It is not suitable for the determination of stream data size in the network bytesRel =
new byte[ in.available()]; in.read(bytesRel); } catch (IOException e) {
log.error(" read file {} fail !"+Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH+fileName);
throw new BizException(IfspRespCode.RESP_ERROR," read pdf File failed !"); }finally { if (in
!= null){ try { in.close(); } catch (IOException e) {
log.error(" Input stream shutdown failed ! reason :{}",e.getMessage()); } } } return bytesRel; }
2. Write file
/** *@author lxw *@date 2020/6/24 *@desc Write file If you want to improve efficiency , You can use buffered streams *@param
[pdfByte, fileName] *@return void **/ public void writePdfFile(byte[]
pdfByte,String fileName) throws Exception{ // Check whether the file already exists , Exist delete
checkFIleExit(fileName,Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH);
OutputStream os = null; try { os = new
FileOutputStream(Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH+fileName);
os.write( pdfByte ) ; os.flush() ; } catch (IOException e) {
log.error(" write file {} fail !"+Constants.PDF_CREATE_AND_SIGN.PDF_FILE_PATH+fileName);
}finally { try { if (os!=null) os.close(); } catch (IOException e) {
log.error(" Input stream shutdown failed ! reason :{}",e.getMessage()); } } } /** *@author lxw *@date
2020/6/23 *@desc Check whether the file exists , Delete if it exists *@param [fileName, path] *@return void **/
public void checkFIleExit(String fileName,String path){
log.info("checkFIleExit Method input parameter :fileName:{},path:{}",fileName,path); File file =
new File(path+fileName); if (file.exists()){ file.delete(); } }
 

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