public void saveImageAsFormat(File fromFile,int targetW,String imgType,String toSaveFile) throws IOException{
BufferedImage srcImage = null,tgtImage=null;
srcImage = ImageIO.read(fromFile);
int type = srcImage.getType();
int targetH=0;
double sx = (double) targetW / srcImage.getWidth();
targetH = (int) (sx * srcImage.getHeight());//获得压缩图片的高度
if (type == BufferedImage.TYPE_CUSTOM) {
ColorModel cm = srcImage.getColorModel();
WritableRaster raster = cm.createCompatibleWritableRaster(targetW,targetH);
boolean alphaPremultiplied = cm.isAlphaPremultiplied();
tgtImage = new BufferedImage(cm, raster, alphaPremultiplied, null);
} else {
tgtImage = new BufferedImage(targetW, targetH, type);
}
Graphics2D g = tgtImage.createGraphics();
g.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g.drawRenderedImage(srcImage, AffineTransform.getScaleInstance(sx, sx));
g.dispose();
File saveFile = new File(toSaveFile);
ImageIO.write(tgtImage, imgType, saveFile);
}
[quote]图片保存到目标路径了，但大小是0，测试了下压缩时间，也是花时间了的，所以和纠结。[/quote]
那你看看在web程序和普通应用程序执行的时候差别在哪里？
[code="java"]我给你个例子
用Java实现zip压缩文件和目录程序代码
今天写了个用java压缩的功能，可以实现对文件和目录的压缩。
由于java.util.zip.ZipOutputStream有中文乱码问题，所以采用org.apache.tools.zip.ZipOutputStream。
以下是代码：
Java代码
package net.szh.zip;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.CRC32;
import java.util.zip.CheckedOutputStream;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipOutputStream;
public class ZipCompressor {
static final int BUFFER = 8192;
private File zipFile;
public ZipCompressor(String pathName) {
zipFile = new File(pathName);
}
public void compress(String srcPathName) {
File file = new File(srcPathName);
if (!file.exists())
throw new RuntimeException(srcPathName + "不存在！");
try {
FileOutputStream fileOutputStream = new FileOutputStream(zipFile);
CheckedOutputStream cos = new CheckedOutputStream(fileOutputStream,
new CRC32());
ZipOutputStream out = new ZipOutputStream(cos);
String basedir = "";
compress(file, out, basedir);
out.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private void compress(File file, ZipOutputStream out, String basedir) {
/* 判断是目录还是文件 */
if (file.isDirectory()) {
System.out.println("压缩：" + basedir + file.getName());
this.compressDirectory(file, out, basedir);
} else {
System.out.println("压缩：" + basedir + file.getName());
this.compressFile(file, out, basedir);
}
}
/** 压缩一个目录 */
private void compressDirectory(File dir, ZipOutputStream out, String basedir) {
if (!dir.exists())
return;
File[] files = dir.listFiles();
for (int i = 0; i < files.length; i++) {
/* 递归 */
compress(files[i], out, basedir + dir.getName() + "/");
}
}
/** 压缩一个文件 */
private void compressFile(File file, ZipOutputStream out, String basedir) {
if (!file.exists()) {
return;
}
try {
BufferedInputStream bis = new BufferedInputStream(
new FileInputStream(file));
ZipEntry entry = new ZipEntry(basedir + file.getName());
out.putNextEntry(entry);
int count;
byte data[] = new byte[BUFFER];
while ((count = bis.read(data, 0, BUFFER)) != -1) {
out.write(data, 0, count);
}
bis.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
本篇文章来自Java中文网：http://www.javaweb.cc/language/java/222365.shtml
[/code]
[code="java"][/code]
看看是否是路径问题或者是
[code="java"]图片不失真的等比例压缩算法：
算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图。
算法讲解：
public void saveMinPhoto(String srcURL,String deskURL,double comBase,double scale){
/*srcURl 原图地址；deskURL 缩略图地址；comBase 压缩基数；scale 压缩限制(宽/高)比例*/
java.io.File srcFile = new java.io.File(srcURL);
Image src = new javax.imageio.ImageIO.read(srcFile);
int srcHeight = src.getHeight(null);
int srcWidth = src.getWidth(null);
int deskHeight = 0;//缩略图高
int deskWidth = 0;//缩略图宽
double srcScale = (double)srcHeight/srcWidth;
if((double)srcHeight>comBase || (double)srcWidth>comBase){
if(srcScale>=scale || 1/srcScale>scale){
if(srcScale>=scale){
deskHeight = (int)comBase;
deskWidth = srcWidth*deskHeight/srcHeight;
}else{
deskWidth = (int)comBase ;
deskHeight = srcHeight*deskWidth/srcWidth;
}
} else {
if((double)srcHeight>comBase){
deskHeight = (int)comBase;
deskWidth = srcWidth*deskHeight/srcHeight;
} else{
deskWidth = (int)comBase ;
deskHeight = srcHeight*deskWidth/srcWidth;
}
}
}else {
deskHeight = srcHeight;
deskWidth = srcWidth;
}
BufferedImage tag = new BufferedImage(deskWidth, deskHeight,
BufferedImage.TYPE_3BYTE_BGR);
tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeighth, null); //绘制缩小后的图
FileOutputStream deskImage = new FileOutputStream(deskURL); //输出到文件流
JPEGImageEncoder encoder = JPEGCodec
.createJPEGEncoder(deskImage);
encoder.encode(tag); //近JPEG编码
deskImage.close();
}
public class ImgProce {
private int wideth;
private int height;
private String t=null;
public void setT(String t)
{
this.t=t;
}
public void setWideth(int wideth)
{
this.wideth=wideth;
}
public int getWideth()
{
return this.wideth;
}
public void setHeight(int height)
{
this.height=height;
}
public int getHeight()
{
if(w > wideth)
{
float ww;
ww = (float) w / (float) wideth;
float hh = h / ww;
return (int) hh;
}
else
{
this.setWideth(w);
return h;
}
}
public void proce(String fpath) throws Exception
{
File _file = new File(fpath);
Image src = javax.imageio.ImageIO.read(_file);
int wideth=src.getWidth(null);
int height=src.getHeight(null);
int h=this.getHeight(wideth,height);
BufferedImage tag = new BufferedImage(this.getWideth(),h,BufferedImage.TYPE_INT_RGB);
Graphics g=tag.getGraphics();
g.drawImage(src, 0, 0, this.getWideth(), h, null);
if(t!=null)
{
g.setColor(new Color(242,242,242));
g.fillRect(this.getWideth() - 120, h - 18,120,18);
g.setColor(new Color(180,180,180));
g.drawRect(this.getWideth() - 120, h - 18,119,17);
g.setColor(new Color(255,102,0));
g.drawString(t, this.getWideth() - 100, h - 5);
}
ImageIO.write(tag, "jpg", new File(fpath));
}
}
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
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 ImageZipUtil {
/**
* 压缩图片文件<br>
* 先保存原文件，再压缩、上传
*
* @param oldFile
* 要进行压缩的文件全路径
* @param width
* 宽度
* @param height
* 高度
* @param quality
* 质量
* @param smallIcon
* 小图片的后缀
* @return 返回压缩后的文件的全路径
*/
public static String zipImageFile(String oldFile, int width, int height,
float quality, String smallIcon) {
if (oldFile == null) {
return null;
}
String newImage = null;
try {
/** 对服务器上的临时文件进行处理 */
Image srcFile = ImageIO.read(new File(oldFile));
int w = srcFile.getWidth(null);
System.out.println(w);
int h = srcFile.getHeight(null);
System.out.println(h);
//width = w/4;
//height = h/4;
/** 宽,高设定 */
BufferedImage tag = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(srcFile, 0, 0, width, height, null);
String filePrex = oldFile.substring(0, oldFile.indexOf('.'));
/** 压缩后的文件名 */
newImage = filePrex + smallIcon
+ oldFile.substring(filePrex.length());
/** 压缩之后临时存放位置 */
FileOutputStream out = new FileOutputStream(newImage);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
JPEGEncodeParam jep = JPEGCodec.getDefaultJPEGEncodeParam(tag);
/** 压缩质量 */
jep.setQuality(quality, true);
encoder.encode(tag, jep);
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return newImage;
}
/**
* 保存文件到服务器临时路径
*
* @param fileName
* @param is
* @return 文件全路径
*/
public static String writeFile(String fileName, InputStream is) {
if (fileName == null || fileName.trim().length() == 0) {
return null;
}
try {
/** 首先保存到临时文件 */
FileOutputStream fos = new FileOutputStream(fileName);
byte[] readBytes = new byte[512];// 缓冲大小
int readed = 0;
while ((readed = is.read(readBytes)) > 0) {
fos.write(readBytes, 0, readed);
}
fos.close();
is.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return fileName;
}
public static void main(String args[]){
ImageZipUtil.zipImageFile("E:/009.jpg", 128, 128, 1f, "x2");
}
}[/code]
web应用中也是调用同样的方法？
检查一下有没有异常抛出