java实现上传图片并压缩图片大小功能

 <!-- 图片缩略图 -->
 <dependency>
 <groupId>net.coobird</groupId>
 <artifactId>thumbnailator</artifactId>
 <version>0.4.8</version>
</dependency>

//按指定大小把图片进行缩和放（会遵循原图高宽比例） 
 //此处把图片压成400×500的缩略图
Thumbnails.of(fromPic).size(400,500).toFile(toPic);

//变为400*300,遵循原图比例缩或放到400*某个高度

//按照比例进行缩小和放大
Thumbnails.of(fromPic).scale(0.2f).toFile(toPic);//按比例缩小
Thumbnails.of(fromPic).scale(2f);//按比例放大

//图片尺寸不变，压缩图片文件大小outputQuality实现,参数1为最高质量
Thumbnails.of(fromPic).scale(1f).outputQuality(0.25f).toFile(toPic);

/**
 * 
 * @Description:保存图片并且生成缩略图
 * @param imageFile 图片文件
 * @param request 请求对象
 * @param uploadPath 上传目录
 * @return
 */
 public static BaseResult uploadFileAndCreateThumbnail(MultipartFile imageFile,HttpServletRequest request,String uploadPath) {
 if(imageFile == null ){
 return new BaseResult(false, "imageFile不能为空");
 }
 
 if (imageFile.getSize() >= 10*1024*1024)
 {
 return new BaseResult(false, "文件不能大于10M");
 }
 String uuid = UUID.randomUUID().toString();
 
 String fileDirectory = CommonDateUtils.date2string(new Date(), CommonDateUtils.YYYY_MM_DD);
 
 //拼接后台文件名称
 String pathName = fileDirectory + File.separator + uuid + "."
  + FilenameUtils.getExtension(imageFile.getOriginalFilename());
 //构建保存文件路劲
 //2016-5-6 yangkang 修改上传路径为服务器上 
 String realPath = request.getServletContext().getRealPath("uploadPath");
 //获取服务器绝对路径 linux 服务器地址 获取当前使用的配置文件配置
 //String urlString=PropertiesUtil.getInstance().getSysPro("uploadPath");
 //拼接文件路劲
 String filePathName = realPath + File.separator + pathName;
 log.info("图片上传路径："+filePathName);
 //判断文件保存是否存在
 File file = new File(filePathName);
 if (file.getParentFile() != null || !file.getParentFile().isDirectory()) {
 //创建文件
 file.getParentFile().mkdirs();
 }
 
 InputStream inputStream = null;
 FileOutputStream fileOutputStream = null;
 try {
 inputStream = imageFile.getInputStream();
 fileOutputStream = new FileOutputStream(file);
 //写出文件
 //2016-05-12 yangkang 改为增加缓存
// IOUtils.copy(inputStream, fileOutputStream);
 byte[] buffer = new byte[2048];
 IOUtils.copyLarge(inputStream, fileOutputStream, buffer);
 buffer = null;

 } catch (IOException e) {
 filePathName = null;
 return new BaseResult(false, "操作失败", e.getMessage());
 } finally {
 try {
 if (inputStream != null) {
  inputStream.close();
 }
 if (fileOutputStream != null) {
  fileOutputStream.flush();
  fileOutputStream.close();
 }
 } catch (IOException e) {
 filePathName = null;
 return new BaseResult(false, "操作失败", e.getMessage());
 } 
 }
 
 
 // String fileId = FastDFSClient.uploadFile(file, filePathName);
 
 /**
 * 缩略图begin
 */
 
 //拼接后台文件名称
 String thumbnailPathName = fileDirectory + File.separator + uuid + "small."
   + FilenameUtils.getExtension(imageFile.getOriginalFilename());
 //added by yangkang 2016-3-30 去掉后缀中包含的.png字符串 
 if(thumbnailPathName.contains(".png")){
 thumbnailPathName = thumbnailPathName.replace(".png", ".jpg");
 }
 long size = imageFile.getSize();
 double scale = 1.0d ;
 if(size >= 200*1024){
 if(size > 0){
 scale = (200*1024f) / size ;
 }
 }
 
 
 //拼接文件路劲
 String thumbnailFilePathName = realPath + File.separator + thumbnailPathName;
 try {
 //added by chenshun 2016-3-22 注释掉之前长宽的方式，改用大小
// Thumbnails.of(filePathName).size(width, height).toFile(thumbnailFilePathName);
 if(size < 200*1024){
 Thumbnails.of(filePathName).scale(1f).outputFormat("jpg").toFile(thumbnailFilePathName);
 }else{
 Thumbnails.of(filePathName).scale(1f).outputQuality(scale).outputFormat("jpg").toFile(thumbnailFilePathName);
 }
 
 } catch (Exception e1) {
 return new BaseResult(false, "操作失败", e1.getMessage());
 }
 /**
 * 缩略图end
 */
 
 Map<String, Object> map = new HashMap<String, Object>();
 //原图地址
 map.put("originalUrl", pathName);
 //缩略图地址
 map.put("thumbnailUrl", thumbnailPathName);
 return new BaseResult(true, "操作成功", map);
 }

 /**
 * 根据key从gzt.properties配置文件获取配置信息 
 * @param key 键值
 * @return
 */
 public String getSysPro(String key){
 return getSysPro(key, null);
 }
 /**
 * 根据key从gzt.properties配置文件获取配置信息 
 * @param key 键值
 * @param defaultValue 默认值
 * @return
 */
 public String getSysPro(String key,String defaultValue){
 return getValue("spring/imageserver-"+System.getProperty("spring.profiles.active")+".properties", key, defaultValue);
 }

//获取服务器绝对路径 linux 服务器地址 
String urlString=PropertiesUtil.getInstance().getSysPro("uploadPath");

package com.xyz.imageserver.common.properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 
 * @ClassName PropertiesUtil.java 
 * @Description 系统配置工具类
 * @author caijy
 * @date 2015年6月9日 上午10:50:38
 * @version 1.0.0
 */
public class PropertiesUtil {
 private Logger logger = LoggerFactory.getLogger(PropertiesUtil.class);
 private ConcurrentHashMap<String, Properties> proMap;
 private PropertiesUtil() {
 proMap = new ConcurrentHashMap<String, Properties>();
 }
 private static PropertiesUtil instance = new PropertiesUtil();

 /**
 * 获取单例对象
 * @return
 */
 public static PropertiesUtil getInstance()
 {
 return instance;
 }
 
 /**
 * 根据key从gzt.properties配置文件获取配置信息 
 * @param key 键值
 * @return
 */
 public String getSysPro(String key){
 return getSysPro(key, null);
 }
 /**
 * 根据key从gzt.properties配置文件获取配置信息 
 * @param key 键值
 * @param defaultValue 默认值
 * @return
 */
 public String getSysPro(String key,String defaultValue){
 return getValue("spring/imageserver-"+System.getProperty("spring.profiles.active")+".properties", key, defaultValue);
 }
 /**
 * 从配置文件中获取对应key值
 * @param fileName 配置文件名
 * @param key key值
 * @param defaultValue 默认值
 * @return
 */
 public String getValue(String fileName,String key,String defaultValue){
 String val = null;
 Properties properties = proMap.get(fileName);
 if(properties == null){
 InputStream inputStream = PropertiesUtil.class.getClassLoader().getResourceAsStream(fileName);
 try {
  properties = new Properties();
 properties.load(new InputStreamReader(inputStream,"UTF-8"));
 proMap.put(fileName, properties);
 val = properties.getProperty(key,defaultValue);
 } catch (IOException e) {
 logger.error("getValue",e);
 }finally{
 try {
  if (inputStream != null) {  
  inputStream.close();
  }
 } catch (IOException e1) {
  logger.error(e1.toString());
 }
 }
 }else{
 val = properties.getProperty(key,defaultValue);
 }
 return val;
 }
}