图片下载

图片下载工具类

package com.zxwa.ntmss.img2text.utils;

import cn.hutool.core.util.StrUtil;
import com.zxwa.ntmss.process.config.OcrConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;


public class FileUtils {
    private static Logger LOG = LoggerFactory.getLogger(FileUtils.class);

    public static void main(String[] args) throws Exception {

    }

    public static byte[] netImage2Bytes(String netUrl) {
        LOG.info("开始下载：" + netUrl);
        byte[] bytes = null;
        try {
            URL url = new URL(netUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5 * 1000);
            InputStream inStream = conn.getInputStream();
            bytes = readInputStream(inStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return bytes;
    }


    public static String netImage2File(String netUrl, String fileLocal) throws Exception {
        LOG.info("开始下载：" + netUrl);
        URL url = new URL(netUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setConnectTimeout(5 * 1000);
        InputStream inStream = conn.getInputStream();
        byte[] data = readInputStream(inStream);
        File imageFile = new File(fileLocal);
        FileOutputStream outStream = new FileOutputStream(imageFile);
        outStream.write(data);
        outStream.close();
        return fileLocal;
    }

   public static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        //创建一个Buffer字符串
        byte[] buffer = new byte[1024];
        //每次读取的字符串长度，如果为-1，代表全部读取完毕
        int len = 0;
        //使用一个输入流从buffer里把数据读取出来
        while ((len = inStream.read(buffer)) != -1) {
            //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
            outStream.write(buffer, 0, len);
        }
        //关闭输入流
        inStream.close();
        //把outStream里的数据写入内存
        return outStream.toByteArray();
    }

    public static byte[] readInputStream(String filePath) throws Exception {
        File file = new File(filePath);
        FileInputStream fis = new FileInputStream(file);
        return readInputStream(fis);
    }
}

 imgio

public static BufferedImage read(File input) throws IOException
 
public static BufferedImage read(InputStream input) throws IOException
 
public static BufferedImage read(URL input) throws IOException
 
public static BufferedImage read(ImageInputStream stream) throws IOException

 案例

/**
     * 网络图片下载
     *
     * @param imageUrl   图片url
     * @param formatName 文件格式名称
     * @param localFile  下载到本地文件
     * @return 下载是否成功
     */
    public static boolean downloadImage(String imageUrl, String formatName, File localFile) {
        boolean isSuccess = false;
        try {
            URL url = new URL(imageUrl);
            isSuccess = ImageIO.write(ImageIO.read(url), formatName, localFile);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return isSuccess;
    }

实际应用：获取图片的大小和尺寸

java获取图片的大小和尺寸，有两种获取的源：

1. 一种是读取本地的图片获取大小和尺寸
2. 一种是通过服务器上图片的地址获取图片的尺寸

/**
  * 本地获取
  * */
 @Test
 public void testImg2() throws IOException{
        File picture = new File("C:/Users/aflyun/Pictures/Camera Roll/1.jpg");
        BufferedImage sourceImg =ImageIO.read(new FileInputStream(picture)); 
        System.out.println(String.format("%.1f",picture.length()/1024.0));// 源图大小
        System.out.println(sourceImg.getWidth()); // 源图宽度
        System.out.println(sourceImg.getHeight()); // 源图高度

 }

 /**
  * 获取服务器上的
  */
 @Test
 public void getImg() throws FileNotFoundException, IOException{
     URL url = new URL("http://img.mall.tcl.com/dev1/0/000/148/0000148235.fid");
     URLConnection connection = url.openConnection();
     connection.setDoOutput(true);
     BufferedImage image = ImageIO.read(connection.getInputStream());  
     int srcWidth = image .getWidth();      // 源图宽度
     int srcHeight = image .getHeight();    // 源图高度

     System.out.println("srcWidth = " + srcWidth);
     System.out.println("srcHeight = " + srcHeight);
 }

 /**
  * 获取服务器上的
  */
 @Test
 public void testImg1() throws IOException{
        InputStream murl = new URL("http://img.mall.tcl.com/dev1/0/000/148/0000148235.fid").openStream();
        BufferedImage sourceImg =ImageIO.read(murl);   
        System.out.println(sourceImg.getWidth());   // 源图宽度
        System.out.println(sourceImg.getHeight());   // 源图高度
 }