压缩某个文件夹里的所有图片

package com.caac.knsgl.utils;

import java.awt.Image;
import java.awt.image.BufferedImage;

import java.io.File;
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.JPEGImageEncoder;

/*******************************************************************************
 * 图片压缩类 缩略图类（通用） 本java类能将jpg、bmp、png、gif图片文件，进行等比或非等比的大小转换。 具体使用方法
 * compressPic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true))
 */
public class ImgCompressUtil {

    private File file = null; // 文件对象
    private String inputDir; // 输入图路径
    private String outputDir; // 输出图路径
    private String inputFileName; // 输入图文件名
    private String outputFileName; // 输出图文件名
    private int outputWidth = 100; // 默认输出图片宽
    private int outputHeight = 100; // 默认输出图片高
    private boolean proportion = true; // 是否等比缩放标记(默认为等比缩放)

    public ImgCompressUtil() { // 初始化变量
        inputDir = "";
        outputDir = "";
        inputFileName = "";
        outputFileName = "";
        outputWidth = 100;
        outputHeight = 100;
    }

    public void setInputDir(String inputDir) {
        this.inputDir = inputDir;
    }

    public void setOutputDir(String outputDir) {
        this.outputDir = outputDir;
    }

    public void setInputFileName(String inputFileName) {
        this.inputFileName = inputFileName;
    }

    public void setOutputFileName(String outputFileName) {
        this.outputFileName = outputFileName;
    }

    public void setOutputWidth(int outputWidth) {
        this.outputWidth = outputWidth;
    }

    public void setOutputHeight(int outputHeight) {
        this.outputHeight = outputHeight;
    }

    public void setWidthAndHeight(int width, int height) {
        this.outputWidth = width;
        this.outputHeight = height;
    }

    /**
     * 获得图片大小 传入参数 String path ：图片路径
     */
    public long getPicSize(String path) {
        file = new File(path);
        return file.length();
    }

    /**
     * 图片处理
     *
     * @return
     */
    public String compressPic() {
        try {
            // 获得源文件
            file = new File(inputDir + inputFileName);
            if (!file.exists()) {
                return "";
            }
            Image img = ImageIO.read(file);
            // 判断图片格式是否正确
            if (img.getWidth(null) == -1) {
                System.out.println(" can't read,retry!" + "<BR>");
                return "no";
            } else {
                int newWidth;
                int newHeight;
                // 判断是否是等比缩放
                if (this.proportion == true) {
                    // 为等比缩放计算输出的图片宽度及高度
                    double rate1 = ((double) img.getWidth(null)) / (double) outputWidth + 0.1;
                    double rate2 = ((double) img.getHeight(null)) / (double) outputHeight + 0.1;
                    // 根据缩放比率大的进行缩放控制
                    double rate = rate1 > rate2 ? rate1 : rate2;
                    newWidth = (int) (((double) img.getWidth(null)) / rate);
                    newHeight = (int) (((double) img.getHeight(null)) / rate);
                } else {
                    newWidth = outputWidth; // 输出的图片宽度
                    newHeight = outputHeight; // 输出的图片高度
                }
                BufferedImage tag = new BufferedImage((int) newWidth, (int) newHeight, BufferedImage.TYPE_INT_RGB);

                /*
                 * Image.SCALE_SMOOTH 的缩略算法 生成缩略图片的平滑度的 优先级比速度高 生成的图片质量比较好 但速度慢
                 */
                tag.getGraphics().drawImage(img.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH), 0, 0, null);
                FileOutputStream out = new FileOutputStream(outputDir + outputFileName);
                // 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 ex) {
            ex.printStackTrace();
        }
        return "ok";
    }

    /**
     * 初始化参数
     *
     * @param inputDir
     *            输入图路径
     * @param outputDir
     *            输出图路径
     * @param inputFileName
     *            输入图文件名
     * @param outputFileName
     *            输出图文件名
     * @return
     */
    public String compressPic(String inputDir, String outputDir, String inputFileName, String outputFileName) {
        // 输入图路径
        this.inputDir = inputDir;
        // 输出图路径
        this.outputDir = outputDir;
        // 输入图文件名
        this.inputFileName = inputFileName;
        // 输出图文件名
        this.outputFileName = outputFileName;
        return compressPic();
    }

    /**
     * 按比例压缩图片
     *
     * @param inputDir
     *            输入图路径
     * @param outputDir
     *            输出图路径
     * @param inputFileName
     *            输入图文件名
     * @param outputFileName
     *            输出图文件名
     * @param width
     *            压缩后的宽度
     * @param height
     *            压缩后的高度
     * @param gp
     *            是否等比缩放
     * @return
     */
    public String compressPic(String inputDir, String outputDir, String inputFileName, String outputFileName, int width,
                              int height, boolean gp) {
        // 输入图路径
        this.inputDir = inputDir;
        // 输出图路径
        this.outputDir = outputDir;
        // 输入图文件名
        this.inputFileName = inputFileName;
        // 输出图文件名
        this.outputFileName = outputFileName;
        // 设置图片长宽
        setWidthAndHeight(width, height);
        // 是否是等比缩放 标记
        this.proportion = gp;
        return compressPic();
    }

    /**
     * 按图片大小(KB单位)循环压缩图片
     *
     * @param oldImgPath
     * @param oldImgName
     * @param newImgPath
     * @param newImgName
     * @param size
     *            KB单位
     * @throws IOException
     */
    public static void cycleImg(String oldImgPath, String oldImgName, String newImgPath, String newImgName,
                                long size) throws IOException {
        ImgCompressUtil mypic = new ImgCompressUtil();
        sameSizeImg(oldImgPath,oldImgName,newImgPath,newImgName);
        long newSize = mypic.getPicSize(newImgPath + newImgName) / 1024;
        if (newSize > size) {
            cycleImg(newImgPath, newImgName, newImgPath, newImgName, size);
        }
    }
    
    /**
     * 按图片原高宽压缩图片
     *
     * @param oldImgPath
     * @param oldImgName
     * @param newImgPath
     * @param newImgName
     * @param size
     *            KB单位
     * @throws IOException
     */
    public static void sameSizeImg(String oldImgPath, String oldImgName, String newImgPath, String newImgName) throws IOException {
        ImgCompressUtil mypic = new ImgCompressUtil();
        File srcFile = new java.io.File(oldImgPath + oldImgName);
        Image src = ImageIO.read(srcFile);
        int srcWidth = src.getWidth(null);
        int srcHeight = src.getHeight(null);
        mypic.compressPic(oldImgPath, newImgPath, oldImgName, newImgName, srcWidth, srcHeight, true);
    }

    // main测试
    // compressPic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true))
    public static void main(String[] arg) throws IOException {
        ImgCompressUtil mypic = new ImgCompressUtil();
        String oldImgPath = "E:\\工作需求\\贫困生申请表\\sourceImg\\";
        String oldImgName = "P60906-104527.jpg";
        String newImgPath = "E:\\工作需求\\贫困生申请表\\targeImg\\";
        String newImgName = "test.jpg";
        long size = 500;
        long oldSize = mypic.getPicSize(oldImgPath + oldImgName) / 1024;
        System.out.println("输入的图片大小：" + oldSize + "KB");
        int start = (int)System.currentTimeMillis();  //开始时间
        //cycleImg(oldImgPath, oldImgName, newImgPath, newImgName, size);
        sameSizeImg(oldImgPath, oldImgName, newImgPath, newImgName);
        int end = (int)System.currentTimeMillis();  //结束时间
        System.out.println("总共用了:"+(end-start)+" 毫秒");
        long newSize = mypic.getPicSize(newImgPath + newImgName) / 1024;
        System.out.println("输出的图片大小：" + newSize + "KB");
    }
}

 

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

import java.util.regex.Pattern;

/**
 * 读取文件夹下的所有附件，并把图片类型压缩公共类
 */
public class ReadFileCompressUtil {
    public ReadFileCompressUtil() {
        super();
    }

    /**
     * 读取某个文件夹下的所有文件，并把图片类型压缩
     * @param filepath  读取的文件夹路径
     * @param targetSize  需要把图片压缩到 targetSize KB单位内
     * @return
     * @throws FileNotFoundException
     * @throws IOException
     */
    public static boolean readfile(String filepath, long targetSize) throws FileNotFoundException, IOException {
        String reg = ".+(.JPEG|.jpeg|.JPG|.jpg|.GIF|.gif|.BMP|.bmp|.PNG|.png)$"; //图片类型 正则表达式
        Pattern pattern = Pattern.compile(reg);
        try {

            File file = new File(filepath);
            if (!file.isDirectory()) { //文件

            } else if (file.isDirectory()) { //文件夹
                String[] filelist = file.list();
                for (int i = 0; i < filelist.length; i++) {
                    File readfile = new File(filepath + "\\" + filelist[i]);
                    if (!readfile.isDirectory()) {
                        String sourcePath = filepath + "\\";
                        String sourceName = readfile.getName();
                        long size = readfile.length() / 1024; //KB
                        
                        if (targetSize >0 && pattern.matcher(sourcePath + sourceName).find() && size > targetSize) { //图片类型，并且大于所需的格式大小,则压缩
                            new ImgCompressUtil().cycleImg(sourcePath, sourceName, sourcePath, sourceName, targetSize);
                        }else{  //不指定压缩大小
                            new ImgCompressUtil().sameSizeImg(sourcePath, sourceName, sourcePath, sourceName);
                        }
                    } else if (readfile.isDirectory()) {
                        readfile(filepath + "\\" + filelist[i], targetSize);
                    }
                }
            }
        } catch (FileNotFoundException e) {
            System.out.println("readfile()   Exception:" + e.getMessage());
        }
        return true;
    }

    public static void main(String[] args) {
        try {
            //1,文件夹路径,压缩图片,指定大小(KB)
//            readfile("E:\\工作需求\\贫困生申请表\\targeImg", 100);
            
            //2,文件夹路径,压缩图片,不指定大小,第二个参数小于0即可
            readfile("E:\\工作需求\\贫困生申请表\\targeImg", -1);
        } catch (FileNotFoundException ex) {
        } catch (IOException ex) {
        }
        System.out.println("ok");
    }

}

 

--摘自 困难生申请的公共类