JAVA中实现图片对象转换成图片文件和字节数组(Byte[ ])的方法讨论

JAVA中实现图片对象转换成图片文件和字节数组(Byte[ ])的方法讨论

网上关于这方面的讨论其实有很多，但找起来也不太容易，笔者以JMSL4.0画出的chart对象为例阐释这一过程，希望能带来些启发。

import com.imsl.chart.*;

import java.awt.image.BufferedImage;

import java.io.*;

import javax.imageio.stream.FileImageOutputStream;

import javax.imageio.stream.ImageOutputStream;

public class SampleImageIO {

public byte[] getByteArray() {

byte[] b = null;

try{

Chart chart = createChart();//generate image

chart.setScreenSize(new java.awt.Dimension(500,500));

BufferedImage bi = new BufferedImage(500, 500, BufferedImage.TYPE_4BYTE_ABGR_PRE);

chart.paintChart(bi.createGraphics()); //generate buffered image

//感觉bufferedimage经常和imageIO成对出现作为对图像对象的标准转化形式。

File file = new File("D:\\workspace\\SampleImageIO1.png");//deploy file

javax.imageio.ImageIO.write(bi, "PNG", file);//generate file

ByteArrayOutputStream bos = new ByteArrayOutputStream();

javax.imageio.ImageIO.write(bi, "png", bos);

b = bos.toByteArray();//generate byte[]

//check to get the byte[]

//其实byte[]的最大的用途应该是网站的图片动态显示，下面的code只是实验一下，也顺便介绍一下byte[]转换成文件的操作。

String newFileName = "d:\\temp\\wine1.png";

FileImageOutputStream imageOutput = new FileImageOutputStream(new File(newFileName));

imageOutput.write(b, 0, b.length);

imageOutput.close();

System.out.println("Please find image in " + newFileName);

}

catch(Exception ex) {

System.out.println("Exception: " + ex);

ex.printStackTrace();

}

return b;

}

//jmsl画图的code，挺快的，好用，但是人家是收费的library～～，抛砖引玉吧

static Chart createChart() {

Chart chart = new Chart();

AxisXY axis = new AxisXY(chart);

int npoints = 20;

double dx = .5 * Math.PI/(npoints-1);

double x[] = new double[npoints];

double y[] = new double[npoints];

// Generate some data

for (int i = 0; i < npoints; i++){

x[i] = i * dx;

y[i] = Math.cos(x[i]);

}

new Data(axis, x, y);

return chart;