Exception in thread "main" java.lang.NoClassDefFoundError

错误出现在第26行，也就是EncodeHintType第一次被调用的那一行，并且E这个类已经在Createqr.java里被import了

package com.ldh.zxing;

import java.io.File;
import java.nio.file.Path;
import java.util.HashMap;

import com.google.zxing.EncodeHintType;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;

//生成二维码
public class CreateQRCode {

 public static void main(String[] args) {
  
  int width = 300;
  int height = 300;
  String format = "png";
  String content = "Hello, i am liu";
  
  //定义二维码参数
  HashMap hints = new HashMap();
  hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
  hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
  hints.put(EncodeHintType.MARGIN, 2);
  
  //生成二维码
  try {
   BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);
   
   Path file = new File("E:/JAVA/zxing/img.png").toPath();
   MatrixToImageWriter.writeToPath(bitMatrix, format, file);
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

}