Java 实现生成图片缩略图,缩小高清图片

import com.sun.image.codec.jpeg.JPEGImageEncoder;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGEncodeParam;import javax.imageio.ImageIO;import java.awt.image.BufferedImage;import java.util.HashMap;import java.util.List;import java.util.ArrayList;import java.io.File;import java.io.IOException;import java.io.FileOutputStream;import java.util.Map;public class ResizeImage {/*** @param im原始图像* @param resizeTimes 需要缩小的倍数，缩小2倍为原来的1/2 ，这个数值越大，返回的图片越小* @return返回处理后的图像*/public BufferedImage resizeImage(BufferedImage im, float resizeTimes) {/*原始图像的宽度和高度*/int width = im.getWidth();int height = im.getHeight();/*调整后的图片的宽度和高度*/int toWidth = (int) (Float.parseFloat(String.valueOf(width)) / resizeTimes);int toHeight = (int) (Float.parseFloat(String.valueOf(height)) / resizeTimes);/*新生成结果图片*/BufferedImage result = new BufferedImage(toWidth, toHeight, BufferedImage.TYPE_INT_RGB);result.getGraphics().drawImage(im.getScaledInstance(toWidth, toHeight, java.awt.Image.SCALE_SMOOTH), 0, 0, null);return result;}/*** @param im原始图像* @param resizeTimes 倍数,比如0.5就是缩小一半,0.98等等double类型* @return返回处理后的图像*/public BufferedImage zoomImage(BufferedImage im, float resizeTimes) {/*原始图像的宽度和高度*/int width = im.getWidth();int height = im.getHeight();/*调整后的图片的宽度和高度*/int toWidth = (int) (Float.parseFloat(String.valueOf(width)) * resizeTimes);int toHeight = (int) (Float.parseFloat(String.valueOf(height)) * resizeTimes);/*新生成结果图片*/BufferedImage result = new BufferedImage(toWidth, toHeight, BufferedImage.TYPE_INT_RGB);result.getGraphics().drawImage(im.getScaledInstance(toWidth, toHeight, java.awt.Image.SCALE_SMOOTH), 0, 0, null);return result;}/*** @param path 要转化的图像的文件夹,就是存放图像的文件夹路径* @param type 图片的后缀名组成的数组* @return*/public List<BufferedImage> getImageList(String path, String[] type) throws IOException{Map<String,Boolean> map = new HashMap<String, Boolean>();for(String s : type) {map.put(s,true);}List<BufferedImage> result = new ArrayList<BufferedImage>();File[] fileList = new File(path).listFiles();for (File f : fileList) {if(f.length() == 0)continue;if(map.get(getExtension(f.getName())) == null)continue;result.add(javax.imageio.ImageIO.read(f));}return result;}/*** 把图片写到磁盘上* @param im* @param patheg: C://home// 图片写入的文件夹地址* @param fileName DCM1987.jpg 写入图片的名字* @return*/public boolean writeToDisk(BufferedImage im, String path, String fileName) {File f = new File(path + fileName);String fileType = getExtension(fileName);if (fileType == null)return false;try {ImageIO.write(im, fileType, f);im.flush();return true;} catch (IOException e) {return false;}}public boolean writeHighQuality(BufferedImage im, String fileFullPath) {try {/*输出到文件流*/FileOutputStream newimage = new FileOutputStream(fileFullPath+System.currentTimeMillis()+".jpg");JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);JPEGEncodeParam jep = JPEGCodec.getDefaultJPEGEncodeParam(im);/* 压缩质量 */jep.setQuality(1f, true);encoder.encode(im, jep);/*近JPEG编码*/newimage.close();return true;} catch (Exception e) {return false;}}/*** 返回文件的文件后缀名* @param fileName* @return*/public String getExtension(String fileName) {try {return fileName.split("\\.")[fileName.split("\\.").length – 1];} catch (Exception e) {return null;}}public static void main(String[] args) throws Exception{String inputFoler = "c:\\cameraImage" ;/*这儿填写你存放要缩小图片的文件夹全地址*/String outputFolder = "c:\\output\\";/*这儿填写你转化后的图片存放的文件夹*/float times = 0.5f;/*这个参数是要转化成的倍数,如果是1就是转化成1倍*/ResizeImage r = new ResizeImage(); List<BufferedImage> imageList = r.getImageList(inputFoler,new String[] {"jpg"});for(BufferedImage i : imageList) {r.writeHighQuality(r.zoomImage(i,times),outputFolder); }}}

如果不能导入jar包就用下面解决方案：

报错：Access restriction:The type JPEGCodec is not accessible due to restriction on required library C:\Program Files\Java\jre6\lib\rt.jar解决方法：Project -> Properties -> libraries，

先remove掉JRE System Library，然后再Add Library重新加入。

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在Eclipse中处理图片，需要引入两个包：import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;报错:Access restriction: The type JPEGImageEncoder is not accessible due to restriction on required library C:\Java\jre1.6.0_07\lib\rt.jar此时解决办法：Eclipse 默认把这些受访问限制的API设成了ERROR。只要把Windows-Preferences-Java-Complicer- Errors/Warnings里面的Deprecated and restricted API中的Forbidden references(access rules)选为Warning就可以编译通过。

优先选择第一种方法

自己在整合在项目中的使用案例：

我们摇摇头说，困难其实没什么大不了。