一个关于图片压缩的java类，大小变小，宽度高度不变

package com.servlet;

import java.awt.Color;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.image.BufferedImage;

import java.awt.image.ConvolveOp;

import java.awt.image.Kernel;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import javax.imageio.ImageIO;

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

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

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

public class ImageCompress {

/**

* 描述：

*

* @param path

* 需要压缩的图片路径

* @param fileName

* 要压缩的图片名称

* @param toFileName

* 压缩后的图片名称

* @param scale

* 压缩比例 不能大于1,默认0.5

* @param quality

* 压缩品质介于0.1~1.0之间

* @param width

* 压缩后的图片的宽度

* @param height

* 压缩后的图片的高度 返回值：void

*/

static void imageCompress(String path, String fileName,

String toFileName, float scale, float quality, int width, int height) {

try { // 原图路径 原图名称 目标路径 压缩比率0.5 0.75 原图宽度 原图高度

long start = System.currentTimeMillis();

Image image = javax.imageio.ImageIO.read(new File(path + fileName));

int imageWidth = image.getWidth(null);

int imageHeight = image.getHeight(null);

if (scale > 0.5)

scale = 0.5f;// 默认压缩比为0.5，压缩比越大，对内存要去越高，可能导致内存溢出

// 按比例计算出来的压缩比

float realscale = getRatio(imageWidth, imageHeight, width, height);

float finalScale = Math.min(scale, realscale);// 取压缩比最小的进行压缩

imageWidth = (int) (finalScale * imageWidth);

imageHeight = (int) (finalScale * imageHeight);

image = image.getScaledInstance(imageWidth, imageHeight,

Image.SCALE_AREA_AVERAGING);

// Make a BufferedImage from the Image.

BufferedImage mBufferedImage = new BufferedImage(imageWidth,

imageHeight, BufferedImage.TYPE_INT_RGB);

Graphics2D g2 = mBufferedImage.createGraphics();

g2.drawImage(image, 0, 0, imageWidth, imageHeight, Color.white,

null);

g2.dispose();

float[] kernelData2 = { -0.125f, -0.125f, -0.125f, -0.125f, 2,

-0.125f, -0.125f, -0.125f, -0.125f };

Kernel kernel = new Kernel(3, 3, kernelData2);

ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);

mBufferedImage = cOp.filter(mBufferedImage, null);

FileOutputStream out = new FileOutputStream(path + toFileName);

System.out.println(path + toFileName);

// JPEGEncodeParam param =

// encoder.getDefaultJPEGEncodeParam(bufferedImage);

// param.setQuality(0.9f, true);

// encoder.setJPEGEncodeParam(param);

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

JPEGEncodeParam param = encoder

.getDefaultJPEGEncodeParam(mBufferedImage);

param.setQuality(quality, true);// 默认0.75

encoder.setJPEGEncodeParam(param);

encoder.encode(mBufferedImage);

out.close();

long end = System.currentTimeMillis();

System.out.println("图片：" + fileName + "，压缩时间：" + (end - start)

+ "ms");

} catch (FileNotFoundException fnf) {

} catch (IOException ioe) {

System.out.println("1111111111111");

//ioe.printStackTrace();

} catch (Exception ex) {

ex.printStackTrace();

} finally {

}

}

public static void imageCompress(String path, String fileName,

String toFileName, float scale, int width, int height) {

imageCompress(path, fileName, toFileName, scale, 0.75f, width, height);

}

private static float getRatio(int width, int height, int maxWidth,

int maxHeight) {// 获得压缩比率的方法

float Ratio = 1.0f;

float widthRatio;

float heightRatio;

widthRatio = (float) maxWidth / width;

heightRatio = (float) maxHeight / height;

if (widthRatio < 1.0 || heightRatio < 1.0) {

Ratio = widthRatio <= heightRatio ? widthRatio : heightRatio;

}

return Ratio;

}

public static byte[] convertImage2Type(String imageFile, String imageType)

throws Exception {// 图片格式转换

File inputFile = new File(imageFile);

ByteArrayOutputStream output = new ByteArrayOutputStream();

BufferedImage input = ImageIO.read(inputFile);

ImageIO.write(input, imageType, output);

return output.toByteArray();

}

public static void convertImage2TypePng(String imageFile, String imageType)

throws Exception {// 图片格式转换

File inputFile = new File(imageFile);

int suffixIndex = imageFile.lastIndexOf(".");

String suffix = imageFile.substring(suffixIndex + 1);

if (!"png".equals(suffix)) {// 如果原图片的不是PNG格式的图片

String fileName = imageFile.substring(0, suffixIndex + 1) + "png";

File output = new File(fileName);

BufferedImage input = ImageIO.read(inputFile);

ImageIO.write(input, imageType, output);

// 转换后删除原文件

if (inputFile.exists())

inputFile.delete();

}

}

}