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;