java 可压缩图片文件上传类

code="java"]
package com.baiying;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.imageio.ImageIO;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class FileUpload {

public FileUpload(){}
private void createDir(String uploadPath){
File file = new File(uploadPath);
//如果该文件目录不存在，则创建一个新的目录
if(!file.exists()){
file.mkdir();
}
}

private File createFile(String uploadPath){
File file = new File(uploadPath);
if(!file.exists()){
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return file;
}
/**
* 得到一个文件输入流
*/
private FileInputStream getStream(String filePath){
FileInputStream fileInputStream  = null;
try {
fileInputStream = new FileInputStream(filePath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
System.out.println("文件没有找到！");
}
return fileInputStream;
}
/**
* 得到一个文件输出流
*/
private FileOutputStream getOutStream(File file){
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(file);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return fileOutputStream;
}
/**
* 文件大小
*/
public Long getFileSize(String filePath){
//判断该文件是否是一个有效的文件
File file = new File(filePath);
if(file.isFile()){
return file.length();
}
return 0l;
}

/**
* 无限制文件上传
* 包含的属性有：上传目录String uploadPath;文件路径String filePath;上传到服务器的文件名称 String fileName;
*/
public boolean upLoad(String uploadPath,String filePath,String fileName){
boolean isSuccess = true;
this.createDir(uploadPath);
String extension = "";
if(filePath!=null&&!filePath.equals("")){
if(filePath.lastIndexOf(".")!=-1){
extension = filePath.substring(filePath.lastIndexOf(".")+1);
}
}
uploadPath = uploadPath + fileName +"."+extension;//上传保存的路径+文件名
File file = this.createFile(uploadPath);//生成新的文件
Pattern pattern = Pattern.compile("bmp|gif|gepg|png|");
Matcher matcher = pattern.matcher(extension);
if(matcher.find()){
//图片
BufferedImage src = null;
            try {
src = javax.imageio.ImageIO.read(new File(filePath));


} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Image image = null;
BufferedImage oimage = null;
image=src.getScaledInstance(src.getWidth(),src.getHeight(),Image.SCALE_DEFAULT);
oimage = new BufferedImage(src.getWidth(),src.getHeight(),Image.SCALE_DEFAULT);
Graphics g = oimage.getGraphics();
g.drawImage(image,0,0, null);
g.dispose();

ByteArrayOutputStream bos = new ByteArrayOutputStream();  
         try {
ImageIO.write(oimage,extension,bos);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}// 输出到bos  

         FileOutputStream out = null;
try {
out = new FileOutputStream(file);
out.write(bos.toByteArray());  //写文件  
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
if(out!=null){
out.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}else{
//非图片
FileInputStream fis = this.getStream(filePath);
BufferedInputStream bis = new BufferedInputStream(fis);
FileOutputStream fos = this.getOutStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead = 0;
byte[] buffer = new byte[8192];
try {
while ((bytesRead = bis.read(buffer, 0, 8192)) != -1) {
bos.write(buffer, 0, bytesRead);// 将文件写入服务器
}
isSuccess = true;
} catch (IOException e) {
// TODO Auto-generated catch block
isSuccess = false;
//e.printStackTrace();
}finally{
try {
if(fos!=null){
    fos.close();
}
if(fis!=null){
fis.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return isSuccess;
}

/**
* 限制文件大小的上传---如果超过一定的大小则压缩或者限制上传
* 包含的属性有：上传目录String uploadPath;文件路径String filePath;上传到服务器的文件名称 String fileName;
*              文件限制大小:int commitSize,大小以k表示
*              boolean flag:true为压缩大小;false为限制上传
*/
public boolean upLoad(String uploadPath,String filePath,String fileName,int commitSize,boolean flag){
//首先要得到上传的文件后缀名，如果不是图片格式的，则将flag属性修改为false，直接限制其上传，如果是图片格式，则对图片进行压缩
String extension = "";
if(filePath!=null&&!filePath.equals("")){
if(filePath.lastIndexOf(".")!=-1){
extension = filePath.substring(filePath.lastIndexOf(".")+1);
}
}
if(flag){
Pattern pattern = Pattern.compile("bmp|gif|gepg|png|");
Matcher matcher = pattern.matcher(extension);
if(matcher.find()){
flag = true;
}else{
flag = false;
}
}

if(flag){
//压缩大小，主要针对于图片
this.upLoad(uploadPath, filePath, fileName);//将图片保存到服务器
//取得服务器的文件，放入一个新的File对象当中
String filePath_new = uploadPath+fileName + "."+extension;
File f = new File(filePath_new);
FileOutputStream out = null;
while(f.length()>commitSize*1000l){

   try {
Image img = ImageIO.read(f);
                BufferedImage tag = new BufferedImage(img.getWidth(null)*9/10,img.getHeight(null)*9/10, BufferedImage.TYPE_INT_RGB);
                 tag.getGraphics().drawImage(img.getScaledInstance(img.getWidth(null)*9/10,img.getHeight(null)*9/10, Image.SCALE_SMOOTH), 0, 0, null);
                 out = new FileOutputStream(filePath_new);
                 // JPEGImageEncoder可适用于其他图片类型的转换
                 JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
                 encoder.encode(tag);
                 out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
if(out!=null){
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
f = new File(filePath_new);
}
}else{
//限制上传
long fileSize = this.getFileSize(filePath);
if(fileSize>commitSize*1000l){
return false;
}else{
return upLoad(uploadPath, filePath, fileName);
}
}

return true;
}

/**
* 加水印的图片上传
*/


/**
* 图片的上传
*/

/**
* 加水印图片
* 包含的属性有：String pressImg,水印图片;String targetImg,目标图片
*/
public  void pressImage(String pressImg, String targetImg,   
            int x, int y) {   
        try {   
            File file = new File(targetImg); 
            Image src = ImageIO.read(file);   
            int wideth = src.getWidth(null);   
            int height = src.getHeight(null);   
            BufferedImage image = new BufferedImage(wideth, height,   
                    BufferedImage.TYPE_INT_RGB);   
            Graphics g = image.createGraphics();   
            g.drawImage(src, 0, 0, wideth, height, null);   
  
            // 水印文件   
            File _filebiao = new File(pressImg);   
            Image src_biao = ImageIO.read(_filebiao);   
            int wideth_biao = src_biao.getWidth(null);   
            int height_biao = src_biao.getHeight(null);   
            g.drawImage(src_biao, wideth - wideth_biao - x, height   
                    - height_biao - y, wideth_biao, height_biao, null);   
            // /   
            g.dispose();   
            FileOutputStream out = new FileOutputStream(targetImg);   
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);   
            encoder.encode(image);   
            out.close();   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
    }   
 
/**
*删除文件  对应属性 String filePath
*/
public  boolean deleteWebFile(String filePath){
        File file = new File(filePath);   
        if(file.isFile() && file.exists()){   
            file.delete();   
            return true;   
        }else{   
            return false;   
        }
}
public static void main(String [] args){
FileUpload f = new FileUpload();
//System.out.println(f.getFileSize("C:\\WINDOWS\\Web\\Wallpaper\\chibi.jpg"));
//System.out.println(f.getFileSize("C:\\WINS\\Web\\Wallpaper\\chijpg"));
//f.upLoad("e:/sstext/", "C:\\WINDOWS\\Web\\Wallpaper\\1920CHINA_2011.jpg", "aaaa");
f.upLoad("E:/sstext/","C:\\WINDOWS\\Web\\Wallpaper\\chibi.jpg","texst",50,true);
}
}




经测试，压缩后图片还未失真！可以根据项目的需求选择是否压缩图片