JAVA 图片URL地址转Byte文件流

图片URL地址转Byte文件流

/**
     * 得到文件流
     * @param url 图片地址
     * @return
     */
    public static byte[] getFileStream(String url){
        try {
            URL httpUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection)httpUrl.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;
    }
 /**
   * 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[1024];
     int len = 0;
     while( (len=inStream.read(buffer)) != -1 ){
         outStream.write(buffer, 0, len);
     }
     inStream.close();
     return outStream.toByteArray();
   }

把文件流Byte转化成Base64字符串

public class Base64Util {
    private static final char last2byte = (char) Integer.parseInt("00000011", 2);
    private static final char last4byte = (char) Integer.parseInt("00001111", 2);
    private static final char last6byte = (char) Integer.parseInt("00111111", 2);
    private static final char lead6byte = (char) Integer.parseInt("11111100", 2);
    private static final char lead4byte = (char) Integer.parseInt("11110000", 2);
    private static final char lead2byte = (char) Integer.parseInt("11000000", 2);
    private static final char[] encodeTable = new char[]{A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, +, /};

    public Base64Util() {
    }

    public static String encode(byte[] from) {
        StringBuilder to = new StringBuilder((int) ((double) from.length * 1.34D) + 3);
        int num = 0;
        char currentByte = 0;

        int i;
        for (i = 0; i < from.length; ++i) {
            for (num %= 8; num < 8; num += 6) {
                switch (num) {
                    case 0:
                        currentByte = (char) (from[i] & lead6byte);
                        currentByte = (char) (currentByte >>> 2);
                    case 1:
                    case 3:
                    case 5:
                    default:
                        break;
                    case 2:
                        currentByte = (char) (from[i] & last6byte);
                        break;
                    case 4:
                        currentByte = (char) (from[i] & last4byte);
                        currentByte = (char) (currentByte << 2);
                        if (i + 1 < from.length) {
                            currentByte = (char) (currentByte | (from[i + 1] & lead2byte) >>> 6);
                        }
                        break;
                    case 6:
                        currentByte = (char) (from[i] & last2byte);
                        currentByte = (char) (currentByte << 4);
                        if (i + 1 < from.length) {
                            currentByte = (char) (currentByte | (from[i + 1] & lead4byte) >>> 4);
                        }
                }

                to.append(encodeTable[currentByte]);
            }
        }

        if (to.length() % 4 != 0) {
            for (i = 4 - to.length() % 4; i > 0; --i) {
                to.append("=");
            }
        }

        return to.toString();
    }
}

base64字符与byte[] 互转

//base64字符串转byte[]
    public static byte[] base64String2ByteFun(String base64Str){
        return Base64.decodeBase64(base64Str);
    }
//byte[]转base64
    public static String byte2Base64StringFun(byte[] b){
        return Base64.encodeBase64String(b);
    }

注意导入 import org.apache.commons.codec.binary.Base64; 包