图片转二进制——各种方法汇总

使用Base64转换图片

     利用Base64实现二进制和图片之间的转换，具体代码如下：

import java.awt.image.BufferedImage;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;import org.apache.tomcat.util.codec.binary.Base64;public class ImageBinary {public static void main(String[] args) {String fileName = "D://code//test.jpg";System.out.println(getImageBinary(fileName));saveImage(getImageBinary(fileName));}/* * 图片转换为二进制 *  * @param fileName *            本地图片路径 * @return *       图片二进制流 * */public static String getImageBinary(String fileName) {File f = new File(fileName);BufferedImage bi;try {bi = ImageIO.read(f);ByteArrayOutputStream baos = new ByteArrayOutputStream();ImageIO.write(bi, "jpg", baos);byte[] bytes = baos.toByteArray();return Base64.encodeBase64String(bytes);//return encoder.encodeBuffer(bytes).trim();} catch (IOException e) {e.printStackTrace();}return null;}/** * 将二进制转换为图片 *  * @param base64String *            图片二进制流 *        */public static void saveImage(String base64String) {try {byte[] bytes1 = Base64.decodeBase64(base64String);ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);BufferedImage bi1 = ImageIO.read(bais);File w2 = new File("D://code//22.jpg");// 可以是jpg,png,gif格式ImageIO.write(bi1, "jpg", w2);// 不管输出什么格式图片，此处不需改动} catch (IOException e) {e.printStackTrace();}}}

url获取图片字节流

    若通过url访问图片并转换为二进制流，就不能按照上述方法。通过url获取图片涉及url、网络状态等各种情况。在代码中涉及两种不同的方法：一个是通过url的形式，另一个是直接访问本地资源（即图片路径）。详见以下代码：

import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;public class ImageUtil {/** * 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;}/** * 根据地址获得数据的字节流 * * @param strUrl *            本地连接地址 * @return */public 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;}/** * 从输入流中获取数据 * * @param inStream *            输入流 * @return * @throws IOException * @throws Exception */private static byte[] readInputStream(InputStream inStream) throws IOException {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();}public static void main(String[] args) {String url = "http://images.cnitblog.com/blog/536814/201412/051633343733092.png";byte[] b = getImageFromNetByUrl(url);System.out.println(b);}}

url获取图片字节流

   本节介绍的方法可以说是前两种方法的结合体，但是在两者的基础上有所优化，如对url的状态做判断，此方法仅供参考，可根据具体需求做相应调整。

import java.awt.image.BufferedImage;import java.io.BufferedInputStream;import java.io.ByteArrayOutputStream;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLConnection;import javax.imageio.ImageIO;import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;public class ImageUtils {    /*     * 获取原图片二进制流     *      * @param imageUrl     *             原图片地址     * */    public static String getImageBinary(String imageUrl) {        String data = null;        try {            int HttpResult = 0; // 服务器返回的状态            URL url = new URL(imageUrl); // 创建URL            URLConnection urlconn = url.openConnection(); // 试图连接并取得返回状态码            urlconn.connect();            HttpURLConnection httpconn = (HttpURLConnection) urlconn;            HttpResult = httpconn.getResponseCode();            if (HttpResult != HttpURLConnection.HTTP_OK) // 不等于HTTP_OK则连接不成功                System.out.print("failed");            else {                BufferedInputStream bis = new BufferedInputStream(urlconn.getInputStream());                BufferedImage bm = ImageIO.read(bis);                ByteArrayOutputStream bos = new ByteArrayOutputStream();                String type = imageUrl.substring(imageUrl.length() - 3);                ImageIO.write(bm, type, bos);                bos.flush();                data = Base64.encode(bos.toByteArray());                bos.close();            }        } catch (Exception e) {            e.printStackTrace();        }        return data;    }    public static void main(String[] args) {        String url = "http://images.cnitblog.com/blog/536814/201412/051633343733092.png";        String result = getImageBinary(url);        System.out.println(result);    }}

url获取图片字节流

   本方法实现了主要实现了以下几个功能：

   1、通过url将图片转换为字节流（十六进制的形式），并实现字节流与图片之间的相互转换；

   2、将本地图片转换为字节流（十六进制的形式），并实现字节流与图片之间的相互转换；

import java.awt.image.BufferedImage;import java.io.BufferedInputStream;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLConnection;import javax.imageio.ImageIO;public class Utils {/** * 图片转换成二进制字符串 *  * @param imageUrl *            图片url * @return String 二进制流 */public static String getImgeHexStringByUrl(String imageUrl) {String res = null;try {int HttpResult = 0; // 服务器返回的状态URL url = new URL(imageUrl); // 创建URLURLConnection urlconn = url.openConnection(); // 试图连接并取得返回状态码urlconn.connect();HttpURLConnection httpconn = (HttpURLConnection) urlconn;HttpResult = httpconn.getResponseCode();if (HttpResult != HttpURLConnection.HTTP_OK) // 不等于HTTP_OK则连接不成功System.out.print("failed");else {BufferedInputStream bis = new BufferedInputStream(urlconn.getInputStream());BufferedImage bm = ImageIO.read(bis);ByteArrayOutputStream bos = new ByteArrayOutputStream();String type = imageUrl.substring(imageUrl.length() - 3);ImageIO.write(bm, type, bos);bos.flush();byte[] data = bos.toByteArray();res = byte2hex(data);bos.close();}} catch (Exception e) {e.printStackTrace();}return res;}/** * 本地图片转换成二进制字符串 *  * @param imageUrl *            图片url * @return String 二进制流 */public static String getImgeHexStringByLocalUrl(String imageUrl) {String res = null;try {File imageFile = new File(imageUrl);InputStream inStream = new FileInputStream(imageFile);BufferedInputStream bis = new BufferedInputStream(inStream);BufferedImage bm = ImageIO.read(bis);ByteArrayOutputStream bos = new ByteArrayOutputStream();String type = imageUrl.substring(imageUrl.length() - 3);ImageIO.write(bm, type, bos);bos.flush();byte[] data = bos.toByteArray();res = byte2hex(data);bos.close();} catch (Exception e) {e.printStackTrace();}return res;}/** * @title 根据二进制字符串生成图片 * @param data *            生成图片的二进制字符串 * @param fileName *            图片名称(完整路径) * @param type *            图片类型 * @return */public static void saveImage(String data, String fileName, String type) {BufferedImage image = new BufferedImage(300, 300, BufferedImage.TYPE_BYTE_BINARY);ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();try {ImageIO.write(image, type, byteOutputStream);// byte[] date = byteOutputStream.toByteArray();byte[] bytes = hex2byte(data);RandomAccessFile file = new RandomAccessFile(fileName, "rw");file.write(bytes);file.close();} catch (IOException e) {e.printStackTrace();}}/** * 反格式化byte *  * @param s * @return */public static byte[] hex2byte(String s) {byte[] src = s.toLowerCase().getBytes();byte[] ret = new byte[src.length / 2];for (int i = 0; i < src.length; i += 2) {byte hi = src[i];byte low = src[i + 1];hi = (byte) ((hi >= 'a' && hi <= 'f') ? 0x0a + (hi - 'a') : hi - '0');low = (byte) ((low >= 'a' && low <= 'f') ? 0x0a + (low - 'a') : low - '0');ret[i / 2] = (byte) (hi << 4 | low);}return ret;}/** * 格式化byte *  * @param b * @return */public static String byte2hex(byte[] b) {char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };char[] out = new char[b.length * 2];for (int i = 0; i < b.length; i++) {byte c = b[i];out[i * 2] = Digit[(c >>> 4) & 0X0F];out[i * 2 + 1] = Digit[c & 0X0F];}return new String(out);}public static void main(String[] args) {String fileName = "D://code//cc.png";String url = "http://images.cnitblog.com/blog/536814/201412/051633343733092.png";String outImage = "D://code//11.png";/* * url形式 * */String result = getImgeHexStringByUrl(url);System.out.println(result);saveImage(result,fileName,"png");/* * 本地图片形式 * */String result1 = getImgeHexStringByLocalUrl(fileName);System.out.println(result1);saveImage(result1,outImage,"png");}}

通过url下载图片

   在给定url的情况下，可将url所访问的图片下载至本地。具体代码如下：

import java.io.BufferedInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.net.HttpURLConnection;import java.net.URL;public class downimageUtil {private static final String filePath = "C://Users//lizhihui//Desktop//";/* * 根据url下载图片 *  * @param  destUrl *             url连接 * @return  *       图片保存路径 * */public String saveToFile(String destUrl) {String fileName = "";FileOutputStream fos = null;BufferedInputStream bis = null;HttpURLConnection httpUrl = null;URL url = null;int BUFFER_SIZE = 1024;byte[] buf = new byte[BUFFER_SIZE];int size = 0;try {url = new URL(destUrl);httpUrl = (HttpURLConnection) url.openConnection();httpUrl.connect();bis = new BufferedInputStream(httpUrl.getInputStream());for (String string : destUrl.split("/")) {if (string.contains("png") || string.contains("png") || string.contains("gif")) {fileName = string;}}fos = new FileOutputStream(filePath + fileName);while ((size = bis.read(buf)) != -1) {fos.write(buf, 0, size);}fos.flush();} catch (IOException e) {} catch (ClassCastException e) {} finally {try {fos.close();bis.close();httpUrl.disconnect();} catch (IOException e) {} catch (NullPointerException e) {}}return filePath + fileName;}public static void main(String[] args) {downimageUtil dw = new downimageUtil();String url = "http://images.cnitblog.com/blog/536814/201412/051633343733092.png";System.out.println(dw.saveToFile(url));}}

   到此，对于图片的处理结束，这是在写图片压缩服务器时所用到的部分技术，当然在此基本上有所改进，在此不再一一列举，对于图片的压缩方法后续也会整理出来，欢迎查看！虽然写出来了，但还没进行压力测试，优化等一系列后续工作。就先这样吧......