java利用zxing包解二维码

我在网上找了一个解二维码的代码，利用的zxing包的功能解码，代码和zxing包都是现成的，编译通过然后运行是有些二维码能解析出来，有些就解析不出来。求大神
package test;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;

import java.net.URLDecoder;

import java.util.EnumMap;

import java.util.Map;

import javax.imageio.ImageIO;

import com.google.zxing.BinaryBitmap;

import com.google.zxing.BufferedImageLuminanceSource;

import com.google.zxing.DecodeHintType;

import com.google.zxing.LuminanceSource;

import com.google.zxing.MultiFormatReader;

import com.google.zxing.Reader;

import com.google.zxing.ReaderException;

import com.google.zxing.Result;

import com.google.zxing.common.HybridBinarizer;

public class ZxingPdfRead {

private static Reader barcodeReader = new MultiFormatReader();

/** 
 * @param args 
 * @throws IOException 
 */  
public static void main(String[] args) throws Exception {  
    File testImage = new File(  
            "E:\\work\\all_workspace\\wp_zxing\\barcode4jTest\\src\\test\\helloworld.png");  

    BufferedImage image = ImageIO.read(testImage);  

    LuminanceSource source = new BufferedImageLuminanceSource(image);  

    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));  

    try {  
        Map<DecodeHintType, Object> hints = new EnumMap<DecodeHintType, Object>(  
                DecodeHintType.class);  

        hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);  

        Result result = barcodeReader.decode(bitmap, hints);  

        String resultText = result.getText();  

        System.out.println("resultText:" + URLDecoder.decode(resultText, "UTF-8"));  
    } catch (ReaderException ignored) {  
        ignored.printStackTrace();  
    }  
}  

}

解析不出来很正常，图片解析度太低，编码不标准，拍照没有对焦，过于偏斜等等都会识别不出来。

图片解析度没问题，手机都能解析出来，而且我是直接用的电脑生成的jpg二维码，不是扫出来保存的。图片不存在问题的