public static String getImgStr(String imgFile){
  //將圖片文件轉(zhuǎn)化為字節(jié)數(shù)組字符串，并對(duì)其進(jìn)行Base64編碼處理
  
  InputStream in = null;
  byte[] data = null;
  //讀取圖片字節(jié)數(shù)組
  try
  {
   in = new FileInputStream(imgFile);  
   data = new byte[in.available()];
   in.read(data);
   in.close();
  }
  catch (IOException e)
  {
   e.printStackTrace();
  }
  return new String(Base64.encodeBase64(data));
 }

public class ReadImageTest {
 public static void main(String[] args) throws IOException {
   FileInputStream fis = new FileInputStream(new File("C:\\Users\\luzhifei\\Pictures\\hc_logo.png"));   
   String picStr="";
   byte[] read = null;
   int len = 0;
   read= new byte[fis.available()];
   fis.read(read);
   String baseStr= Base64.getEncoder().encodeToString(read);
   //System.out.println( baseStr);
   byte[] op= Base64.getDecoder().decode(baseStr);
   // System.out.println(new String(op));
   FileOutputStream fos = new FileOutputStream(new File("d:\\temp\\1.jpg"));
   fos.write(op,0,op.length );
   fos.flush();
   fos.close();
 }
}

public static void imageToBase64Str() throws IOException{
   FileInputStream fis = new FileInputStream(new File("C:\\Users\\luzhifei\\Pictures\\hc_logo.png"));
   byte[] read = new byte[1024];
   int len = 0;
   List<byte[]> blist=new ArrayList<byte[]>();
   int ttllen=0;
   while((len = fis.read(read))!= -1){
    byte[] dst=new byte[len];
    System.arraycopy(read, 0, dst, 0, len);
    ttllen+=len;
    blist.add(dst);
   }
   fis.close();
   byte[] dstByte=new byte[ttllen];
   int pos=0;
   for (int i=0;i<blist.size();i++){
    if (i==0){
     pos=0;
    }
    else{
    pos+=blist.get(i-1).length; 
    }
    System.arraycopy(blist.get(i), 0, dstByte, pos, blist.get(i).length);
   }
   String baseStr= Base64.getEncoder().encodeToString(dstByte);
   byte[] op= Base64.getDecoder().decode(baseStr);
   FileOutputStream fos = new FileOutputStream(new File("d:\\temp\\2.jpg"));
   fos.write(op,0,op.length );
   fos.flush();
   fos.close();
 }