项目中需要用到二维码，二维码的码制是PDF417，在做了一番研究之后发现zxing是个不错的开源工具（代码托管在google上面）。为什么选择zxing，由于其他一些工具比如barcode4j（开源，支持读，好像不支持写，最后维护时间在2010年）、barcode（商业版）都不太适合，所以选择了zxing。
zxing并没有提供直接可以使用的jar文件，而是需要自己通过编译源码，生成需要的jar文件。额外说明，zxing利用maven管理自己的代码，并且默认使用了jdk7，代码中也使用了jdk7的一些新特性，基于这些情况，可以适当调整jdk的版本（如果降低jdk的版本，需要改动少量的源码）。
下面直接贴出读写文件的代码：
ZxingPdfRead
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();
}
}
}
ZxingPdfWrite
package test;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.URLEncoder;
import javax.imageio.ImageIO;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.pdf417.PDF417Writer;
public class ZxingPdfWrite {
private static final int BLACK = 0xff000000;
private static final int WHITE = 0xFFFFFFFF;
/**
* @param args
* @throws WriterException
*/
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
PDF417Writer pdf417Writer = new PDF417Writer();
//注意中文乱码问题
BitMatrix bitMatrix = pdf417Writer.encode(URLEncoder.encode("我是中国人","UTF-8"),
BarcodeFormat.PDF_417, 100, 50);
writeToFile(bitMatrix,"png",new File("E:\\work\\all_workspace\\wp_zxing\\barcode4jTest\\src\\test\\helloworld.png"));
}
public static void writeToFile(BitMatrix matrix, String format, File file)
throws IOException {
BufferedImage image = toBufferedImage(matrix);
ImageIO.write(image, format, file);
}
public static BufferedImage toBufferedImage(BitMatrix matrix) {
int width = matrix.getWidth();
int height = matrix.getHeight();
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_ARGB);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
image.setRGB(x, y, matrix.get(x, y) == true ? BLACK : WHITE);
}
}
return image;
}
}
BufferedImageLuminanceSource.java
/*
* Copyright 2009 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import com.google.zxing.LuminanceSource;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.geom.AffineTransform;
/**
* This LuminanceSource implementation is meant for J2SE clients and our blackbox unit tests.
*
* @author dswitkin@google.com (Daniel Switkin)
* @author Sean Owen
*/
public final class BufferedImageLuminanceSource extends LuminanceSource {
private final BufferedImage image;
private final int left;
private final int top;
private int[] rgbData;
public BufferedImageLuminanceSource(BufferedImage image) {
this(image, 0, 0, image.getWidth(), image.getHeight());
}
public BufferedImageLuminanceSource(BufferedImage image, int left, int top, int width,
int height) {
super(width, height);
int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();
if (left + width > sourceWidth || top + height > sourceHeight) {
throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
}
this.image = image;
this.left = left;
this.top = top;
}
// These methods use an integer calculation for luminance derived from:
// <code>Y = 0.299R + 0.587G + 0.114B</code>
@Override
public byte[] getRow(int y, byte[] row) {
if (y < 0 || y >= getHeight()) {
throw new IllegalArgumentException("Requested row is outside the image: " + y);
}
int width = getWidth();
if (row == null || row.length < width) {
row = new byte[width];
}
if (rgbData == null || rgbData.length < width) {
rgbData = new int[width];
}
image.getRGB(left, top + y, width, 1, rgbData, 0, width);
for (int x = 0; x < width; x++) {
int pixel = rgbData[x];
int luminance = (306 * ((pixel >> 16) & 0xFF) +
601 * ((pixel >> 8) & 0xFF) +
117 * (pixel & 0xFF)) >> 10;
row[x] = (byte) luminance;
}
return row;
}
@Override
public byte[] getMatrix() {
int width = getWidth();
int height = getHeight();
int area = width * height;
byte[] matrix = new byte[area];
int[] rgb = new int[area];
image.getRGB(left, top, width, height, rgb, 0, width);
for (int y = 0; y < height; y++) {
int offset = y * width;
for (int x = 0; x < width; x++) {
int pixel = rgb[offset + x];
int luminance = (306 * ((pixel >> 16) & 0xFF) +
601 * ((pixel >> 8) & 0xFF) +
117 * (pixel & 0xFF)) >> 10;
matrix[offset + x] = (byte) luminance;
}
}
return matrix;
}
@Override
public boolean isCropSupported() {
return true;
}
@Override
public LuminanceSource crop(int left, int top, int width, int height) {
return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
}
// Can't run AffineTransforms on images of unknown format.
@Override
public boolean isRotateSupported() {
return image.getType() != BufferedImage.TYPE_CUSTOM;
}
@Override
public LuminanceSource rotateCounterClockwise() {
if (!isRotateSupported()) {
throw new IllegalStateException("Rotate not supported");
}
int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();
// Rotate 90 degrees counterclockwise.
AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);
// Note width/height are flipped since we are rotating 90 degrees.
BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, image.getType());
// Draw the original image into rotated, via transformation
Graphics2D g = rotatedImage.createGraphics();
g.drawImage(image, transform, null);
g.dispose();
// Maintain the cropped region, but rotate it too.
int width = getWidth();
return new BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width),
getHeight(), width);
}
}