针对图片压缩处理，只改变其内存大小

package test;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Iterator;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.FileImageInputStream;
import javax.imageio.stream.FileImageOutputStream;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImgUtil {
	
	
	/**
	* @Title: compressPic 
	* @Description: 压缩图片,通过压缩图片质量，保持原图大
	* @param  quality:0-1    
	* @return byte[] 
	* @throws
	*/
	public static byte[] compressPic(byte[] imageByte,float quality) {
	byte[] inByte = null;
	try {
	ByteArrayInputStream byteInput = new ByteArrayInputStream(imageByte);
	Image img = ImageIO.read(byteInput);
	float newWidth = img.getWidth(null);
	float newHeight = img.getHeight(null);

	Image image = img.getScaledInstance((int) newWidth,(int) newHeight, Image.SCALE_SMOOTH);


	// 缩放图像
	BufferedImage tag = new BufferedImage((int) newWidth,
	(int) newHeight, BufferedImage.TYPE_INT_RGB);
	Graphics2D g = tag.createGraphics();
	g.drawImage(image, 0, 0, null); // 绘制缩小后的
	g.dispose();
	ByteArrayOutputStream out = new ByteArrayOutputStream(imageByte.length);
	JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
	            JPEGEncodeParam jep=JPEGCodec.getDefaultJPEGEncodeParam(tag); 
	            /* 压缩质量 */ 
	            jep.setQuality((float)0.6, true); 
	            encoder.encode(tag, jep); 
	            inByte = out.toByteArray();
	            out.close(); 

	} catch (IOException ex) {
	ex.printStackTrace();
	}
	return inByte;
	}
	
	
	/**
	 * byte数组到图片
	 * @param data
	 * @param path
	 */
    public static void byte2image(byte[] data,String path){
      if(data.length<3||path.equals("")) return;
      try{
      FileImageOutputStream imageOutput = new FileImageOutputStream(new File(path));
      imageOutput.write(data, 0, data.length);
      imageOutput.close();
      System.out.println("Make Picture success,Please find image in " + path);
      } catch(Exception ex) {
        System.out.println("Exception: " + ex);
        ex.printStackTrace();
      }
    }
    
    
    /**
     * 图片到byte数组
     * @param path
     * @return
     */
    public static byte[] image2byte(String path){
      byte[] data = null;
      FileImageInputStream input = null;
      try {
        input = new FileImageInputStream(new File(path));
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        byte[] buf = new byte[1024];
        int numBytesRead = 0;
        while ((numBytesRead = input.read(buf)) != -1) {
        output.write(buf, 0, numBytesRead);
        }
        data = output.toByteArray();
        output.close();
        input.close();
      }
      catch (FileNotFoundException ex1) {
        ex1.printStackTrace();
      }
      catch (IOException ex1) {
        ex1.printStackTrace();
      }
      return data;
    }
    
    /**
     * 压缩图片第二种方法
     * @param imgByte
     * @param quality
     * @return
     */
    public static byte[] compressPicByQuality(byte[] imgByte, float quality) {
    	byte[] inByte = null;
    	try {
    	ByteArrayInputStream byteInput = new ByteArrayInputStream(imgByte);
    	BufferedImage image = ImageIO.read(byteInput);

    	// 如果图片空，返回空
    	if (image == null) {
    	return null;
    	} 
    	// 得到指定Format图片的writer
    	Iterator<ImageWriter> iter = ImageIO
    	.getImageWritersByFormatName("jpeg");// 得到迭代器
    	ImageWriter writer = (ImageWriter) iter.next(); // 得到writer

    	// 得到指定writer的输出参数设置(ImageWriteParam )
    	ImageWriteParam iwp = writer.getDefaultWriteParam();
    	iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT); // 设置可否压缩
    	iwp.setCompressionQuality(quality); // 设置压缩质量参数

    	iwp.setProgressiveMode(ImageWriteParam.MODE_DISABLED);

    	ColorModel colorModel = ColorModel.getRGBdefault();
    	// 指定压缩时使用的色彩模式
    	iwp.setDestinationType(new javax.imageio.ImageTypeSpecifier(colorModel,
    	colorModel.createCompatibleSampleModel(16, 16)));

    	// 开始打包图片，写入byte[]
    	ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); // 取得内存输出流
    	IIOImage iIamge = new IIOImage(image, null, null);

    	// 此处因为ImageWriter中用来接收write信息的output要求必须是ImageOutput
    	// 通过ImageIo中的静态方法，得到byteArrayOutputStream的ImageOutput
    	writer.setOutput(ImageIO
    	.createImageOutputStream(byteArrayOutputStream));
    	writer.write(null, iIamge, iwp);
    	inByte = byteArrayOutputStream.toByteArray();
    	} catch (IOException e) {
    	e.printStackTrace();
    	}
    	return inByte;
    	}
}package test;

import java.awt.Graphics2D;
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