网上图片本地保存并进行压缩操作

package com.demo.wnb;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

import javax.imageio.ImageIO;

public class PictureCompress {
	public static void main(String args[]) {  
        try {  
        	getPic("http://pic.58pic.com/58pic/16/62/63/97m58PICyWM_1024.jpg");
            Map<Integer, String> map = readfile("C:/Users/wnb/Desktop/pic", null);  
            for (int i = 0; i < map.size(); i++) { 
                compressImage(map.get(i), "C:/Users/wnb/Desktop/_" + i + ".png", 100, 75);
                //compressImage(map.get(i), "C:/Users/wnb/Desktop/_" + i + ".png", 100);  
            }  
        } catch (Exception e) {  
        	e.printStackTrace();
        }  
    }
	
	private static void getPic(String path) throws Exception{
		URL url = new URL(path);  //new一个URL对象
		HttpURLConnection conn = (HttpURLConnection)url.openConnection();//打开链接    
		conn.setRequestMethod("GET");  //设置请求方式为"GET" 
		conn.setConnectTimeout(5 * 1000);  //超时响应时间为5秒  
		InputStream inStream = conn.getInputStream(); //通过输入流获取图片数据   
		byte[] data = readInputStream(inStream);  //得到图片的二进制数据，以二进制封装得到数据，具有通用性
		File file = new File("C:\\Users\\wnb\\Desktop\\pic");  //new一个文件对象用来保存图片，默认保存当前工程根目录 
		if (!file.exists()){	//若此目录不存在，则创建  
			file.mkdir();  
        }
		File imageFile = new File("C:\\Users\\wnb\\Desktop\\pic\\1.jpg");
		FileOutputStream outStream = new FileOutputStream(imageFile);//创建输出流  
		outStream.write(data);  //写入数据  
		outStream.close();//关闭输出流  
	}
	
	public static byte[] readInputStream(InputStream inStream) throws Exception{  
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();  
        byte[] buffer = new byte[1024];  //创建一个Buffer字符串  
        int len = 0;  //每次读取的字符串长度，如果为-1，代表全部读取完毕 
        //使用一个输入流从buffer里把数据读取出来  
        while( (len=inStream.read(buffer)) != -1 ){  
            outStream.write(buffer, 0, len);  //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 
        }  
        inStream.close(); //关闭输入流    
        return outStream.toByteArray();  //把outStream里的数据写入内存  
    }  
      
      
    /**  
     * 图片文件读取  
     * @param srcImgPath  
     * @return  
     */  
    private static BufferedImage InputImage(String srcImgPath) {  
        BufferedImage srcImage = null;  
        try {  
            FileInputStream in = new FileInputStream(srcImgPath);  
            srcImage = javax.imageio.ImageIO.read(in);  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
        return srcImage;  
    }  
  
    /** 
     * * 将图片按照指定的图片尺寸压缩 
     * @param srcImgPath :源图片路径 
     * @param outImgPath  :输出的压缩图片的路径  
     * @param new_w :压缩后的图片宽 
     * @param new_h :压缩后的图片高 
     */  
    public static void compressImage(String srcImgPath, String outImgPath,  
            int new_w, int new_h) {  
        BufferedImage src = InputImage(srcImgPath);  
        disposeImage(src, outImgPath, new_w, new_h);  
    }  
  
    /** 
     * 指定长或者宽的最大值来压缩图片  
     * @param srcImgPath :源图片路径  
     * @param outImgPath :输出的压缩图片的路径  
     * @param maxLength :长或者宽的最大值 
     */  
    public static void compressImage(String srcImgPath, String outImgPath,  
            int maxLength) {  
        // 得到图片  
        BufferedImage src = InputImage(srcImgPath);  
        if (null != src) {  
            int old_w = src.getWidth();  // 得到源图宽  
            int old_h = src.getHeight();  // 得到源图长  
            int new_w = 0; // 新图的宽  
            int new_h = 0; // 新图的长  
            // 根据图片尺寸压缩比得到新图的尺寸  
            if (old_w > old_h) {  
                // 图片要缩放的比例  
                new_w = maxLength;  
                new_h = (int) Math.round(old_h * ((float) maxLength / old_w));  
            } else {  
                new_w = (int) Math.round(old_w * ((float) maxLength / old_h));  
                new_h = maxLength;  
            }  
            disposeImage(src, outImgPath, new_w, new_h);  
        }  
    }  
  
    /**  
     * 处理图片 
     * @param src  
     * @param outImgPath  
     * @param new_w  
     * @param new_h  
     */  
    private synchronized static void disposeImage(BufferedImage src,  
            String outImgPath, int new_w, int new_h) {  
        // 得到图片  
        int old_w = src.getWidth();  
        // 得到源图宽  
        int old_h = src.getHeight();  
        // 得到源图长  
        BufferedImage newImg = null;  
        // 判断输入图片的类型  
        switch (src.getType()) {  
        case 13:  
            //png,gif格式
        	//newImg = new BufferedImage(new_w, new_h,BufferedImage.TYPE_4BYTE_ABGR);  
            break;  
        default:  
            newImg = new BufferedImage(new_w, new_h, BufferedImage.TYPE_INT_RGB);  
            break;  
        }  
        Graphics2D g = newImg.createGraphics();  
        // 从原图上取颜色绘制新图  
        g.drawImage(src, 0, 0, old_w, old_h, null);  
        g.dispose();  
        // 根据图片尺寸压缩比得到新图的尺寸  
        newImg.getGraphics().drawImage(  
                src.getScaledInstance(new_w, new_h, Image.SCALE_SMOOTH), 0, 0,null);  
        // 调用方法输出图片文件  
        OutImage(outImgPath, newImg);  
    }  
  
    /** 
     * 将图片文件输出到指定的路径，并可设定压缩质量  
     * @param outImgPath  
     * @param newImg  
     * @param per 
     */  
    private static void OutImage(String outImgPath, BufferedImage newImg) {  
        //判断输出的文件夹路径是否存在，不存在则创建  
        File file = new File(outImgPath);  
        if (!file.getParentFile().exists()) {  
            file.getParentFile().mkdirs();  
        }
        // 输出到文件流  
        try {  
            ImageIO.write(newImg,outImgPath.substring(outImgPath.lastIndexOf(".") + 1),  
                    new File(outImgPath));  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
  
    /**
     * 图片路径读取
     * @param filepath
     * @param pathMap
     * @return
     * @throws Exception
     */
    public static Map<Integer, String> readfile(String filepath,  
            Map<Integer, String> pathMap) throws Exception {  
        if (pathMap == null) {  
            pathMap = new HashMap<Integer, String>();  
        }  
        File file = new File(filepath);  
        // 文件  
        if (!file.isDirectory()) {  
            pathMap.put(pathMap.size(), file.getPath());  
  
        } else if (file.isDirectory()) { // 如果是目录， 遍历所有子目录取出所有文件名  
            String[] filelist = file.list();  
            for (int i = 0; i < filelist.length; i++) {  
                File readfile = new File(filepath + "/" + filelist[i]);  
                if (!readfile.isDirectory()) {  
                    pathMap.put(pathMap.size(), readfile.getPath());  
                } else if (readfile.isDirectory()) { // 子目录的目录  
                    readfile(filepath + "/" + filelist[i], pathMap);  
                }  
            }  
        }  
        return pathMap;  
    }  
}