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Java obtains the remote network image file stream, compresses it and saves it locally

高洛峰
Release: 2016-11-21 11:14:57
Original
5061 people have browsed it

java gets the image file stream from the remote network, compresses it and saves it locally

1. Get the image from the remote network

     /**
 * 根据地址获得数据的字节流
 *
 * @param strUrl
 *            网络连接地址
 * @return
 */
public static byte[] getImageFromNetByUrl(String strUrl) {
    try {
        URL url = new URL(strUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setConnectTimeout(5 * 1000);
        InputStream inStream = conn.getInputStream();// 通过输入流获取图片数据
        byte[] btImg = readInputStream(inStream);// 得到图片的二进制数据
        return btImg;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}
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 /**
 * 根据地址获得数据的字节流
 *
 * @param strUrl
 *            本地连接地址
 * @return
 */
public static byte[] getImageFromLocalByUrl(String strUrl) {
    try {
        File imageFile = new File(strUrl);
        InputStream inStream = new FileInputStream(imageFile);
        byte[] btImg = readInputStream(inStream);// 得到图片的二进制数据
        return btImg;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}
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   /**
 * 从输入流中获取数据
 *
 * @param inStream
 *            输入流
 * @return
 * @throws Exception
 */
public static byte[] readInputStream(InputStream inStream) throws Exception {
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    byte[] buffer = new byte[10240];
    int len = 0;
    while ((len = inStream.read(buffer)) != -1) {
        outStream.write(buffer, 0, len);
    }
    inStream.close();
    return outStream.toByteArray();
}  
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2. Convert the file read from the network into a local file

       byte[] btImg1 = ImageUtil.getImageFromNetByUrl(fileUrl1);
if (null != btImg1 && btImg1.length > 0) {
    logger.debug("读取到:" + btImg1.length + " 字节");
    ImageUtil.writeImageToDisk(btImg1, fileZipUrl1);
} else {
    logger.debug("没有从该连接获得内容");
}
 
byte[] btImg2 = ImageUtil.getImageFromNetByUrl(fileUrl2);
if (null != btImg2 && btImg2.length > 0) {
    logger.debug("读取到:" + btImg2.length + " 字节");
    ImageUtil.writeImageToDisk(btImg2, fileZipUrl2);
} else {
    logger.debug("没有从该连接获得内容");
}
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/**
 * 将图片写入到磁盘
 *
 * @param img
 *            图片数据流
 * @param fileName
 *            文件保存时的名称
 */
public static void writeImageToDisk(byte[] img, String zipImageUrl) {
    try {
        File file = new File(zipImageUrl);
        FileOutputStream fops = new FileOutputStream(file);
        fops.write(img);
        fops.flush();
        fops.close();
        System.out.println("图片已经写入"+zipImageUrl);
    } catch (Exception e) {
        e.printStackTrace();
    }
}
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3. Compress the local image

import java.io.*; 
import java.util.Date; 
import java.awt.*; 
import java.awt.image.*; 
import javax.imageio.ImageIO; 
import com.sun.image.codec.jpeg.*; 
/**
 * 图片压缩处理
 */ 
public class ImgCompress { 
    private Image img; 
    private int width; 
    private int height;  
    /**
     * 构造函数
     */ 
    public ImgCompress(String fileName) throws IOException { 
        File file = new File(fileName);// 读入文件 
        img = ImageIO.read(file);      // 构造Image对象 
        width = img.getWidth(null);    // 得到源图宽 
        height = img.getHeight(null);  // 得到源图长 
    } 
    /**
     * 按照宽度还是高度进行压缩
     * @param w int 最大宽度
     * @param h int 最大高度
     */ 
    public void resizeFix(int w, int h) throws IOException { 
        if (width / height > w / h) { 
            resizeByWidth(w); 
        } else { 
            resizeByHeight(h); 
        } 
    } 
    /**
     * 以宽度为基准,等比例放缩图片
     * @param w int 新宽度
     */ 
    public void resizeByWidth(int w) throws IOException { 
        int h = (int) (height * w / width); 
        resize(w, h); 
    } 
    /**
     * 以高度为基准,等比例缩放图片
     * @param h int 新高度
     */ 
    public void resizeByHeight(int h) throws IOException { 
        int w = (int) (width * h / height); 
        resize(w, h); 
    } 
    /**
     * 强制压缩/放大图片到固定的大小
     * @param w int 新宽度
     * @param h int 新高度
     */ 
    public void resize(int w, int h) throws IOException { 
        // 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 
        BufferedImage image = new BufferedImage(w, h,BufferedImage.TYPE_INT_RGB );  
        image.getGraphics().drawImage(img, 0, 0, w, h, null); // 绘制缩小后的图 
        File destFile = new File("C:/Users/Administrator/Desktop/147.jpg"); 
        FileOutputStream out = new FileOutputStream(destFile); // 输出到文件流 
        // 可以正常实现bmp、png、gif转jpg 
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
        encoder.encode(image); // JPEG编码 
        out.close(); 
    }
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@SuppressWarnings("deprecation") 
public static void main(String[] args) throws Exception { 
    System.out.println("开始:" + new Date().toLocaleString()); 
    ImgCompress imgCom = new  ImgCompress("C:/Users/Administrator/Desktop/1479209533362.jpg"); 
    imgCom.resizeFix(285, 380); 
    System.out.println("结束:" + new Date().toLocaleString()); 
}
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}
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End ~

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