Java io流 從網絡讀取圖片並保存至本地

package getUrlPic;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class GetUrlPic {
    
    public static void main(String[] args) throws Exception {  
        //new一個URL對象  
        URL url = new URL("http://www.gz135.cn/data/attachment/forum/201702/13/165605xyayykq5vy4h81vy.jpg");  
        //打開鏈接  
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();  
        //設置請求方式爲"GET"  
        conn.setRequestMethod("GET");  
        //超時響應時間爲5秒  
        conn.setConnectTimeout(5 * 1000);  
        //通過輸入流獲取圖片數據  
        InputStream inStream = conn.getInputStream();  
        //得到圖片的二進制數據，以二進制封裝得到數據，具有通用性  
        byte[] data = readInputStream(inStream);  
        //new一個文件對象用來保存圖片，默認保存當前工程根目錄  
        File imageFile = new File("pic20170419.jpg");  
        //創建輸出流  
        FileOutputStream outStream = new FileOutputStream(imageFile);  
        //寫入數據  
        outStream.write(data);  
        //關閉輸出流  
        outStream.close();  
    }  
    public static byte[] readInputStream(InputStream inStream) throws Exception{  
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();  
        //創建一個Buffer字符串  
        byte[] buffer = new byte[1024];  
        //每次讀取的字符串長度，如果爲-1，代表全部讀取完畢  
        int len = 0;  
        //使用一個輸入流從buffer裏把數據讀取出來  
        while( (len=inStream.read(buffer)) != -1 ){  
            //用輸出流往buffer裏寫入數據，中間參數代表從哪個位置開始讀，len代表讀取的長度  
            outStream.write(buffer, 0, len);  
        }  
        //關閉輸入流  
        inStream.close();  
        //把outStream裏的數據寫入內存  
        return outStream.toByteArray();  
    }  

}

原文地址：https://www.cnblogs.com/zhao1949/p/6731601.html