Base64流式处理Java实现

package com.lz.utils; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.nio.charset.Charset; import java.util.Arrays; import java.util.HashMap; import java.util.Map; import org.apache.tools.ant.filters.StringInputStream; import com.sun.xml.internal.messaging.saaj.util.ByteOutputStream; /** * Base64编码工具 * * @author liuz * @date 2017年8月31日 下午1:34:26 */ public class Base64Utils { /** Base64编码ascii码与字符值表 */ private static final char[] BASE64_CHAR_MAP = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" .toCharArray(); private static final char BASE64_COVER_CHAR = '='; // 缓存块大小（可调优，1024*3可以 957毫秒编码53.6M数据，1896毫秒解码还原,大于1024*3后速度增长不明显） private static final int BUFFER_SIZE = 1024 * 3; private static Map<Byte,Byte> reMap; // 逆向映射表 static{ reMap = new HashMap<Byte,Byte>(); for(byte i = 0; i < BASE64_CHAR_MAP.length; i++){ reMap.put((byte)BASE64_CHAR_MAP[i], i); } } /** * Base64编码-流式处理 * * @param is * 输入流 * @param os * 输出流 * @throws IOException */ public static void encode(InputStream is, OutputStream os) throws IOException { byte[] buffer = new byte[BUFFER_SIZE]; Arrays.fill(buffer, (byte) 0x00); int rlen = -1; while ((rlen = is.read(buffer)) != -1) { int coverSize = (3 - (rlen % 3)) % 3; int byteSize = rlen + coverSize; // 总字节数 int asciiSize = byteSize * 8 / 6; byte[] oBuffer = new byte[asciiSize]; // 每次取一个6bit的ascci for (int i = 0; i < asciiSize; i++) { byte k = getByte826(buffer, i); oBuffer[i] = (byte) BASE64_CHAR_MAP[k]; } Arrays.fill(buffer, (byte) 0x00); if (coverSize == 1) { oBuffer[asciiSize - 1] = BASE64_COVER_CHAR; } else if (coverSize == 2) { oBuffer[asciiSize - 1] = BASE64_COVER_CHAR; oBuffer[asciiSize - 2] = BASE64_COVER_CHAR; } os.write(oBuffer); } } /** * Base64编码-字符串处理 * * @param data * @return */ public static String encode(String data) { StringInputStream sis = new StringInputStream(data); ByteOutputStream bos = new ByteOutputStream(); try { encode(sis, bos); } catch (IOException e) { e.printStackTrace(); } return bos.toString(); } /** * Base64加密 - byte数组实现 * * @param data * @return */ public static String encode(byte[] data) { ByteArrayInputStream bis = new ByteArrayInputStream(data); ByteOutputStream bos = new ByteOutputStream(); try { encode(bis, bos); } catch (IOException e) { e.printStackTrace(); } return bos.toString(); } /** * Base64解码 - 流式处理 * * @param is * 输入流 * @param os * 输出流 * @throws IOException */ public static void decode(InputStream is, OutputStream os) throws IOException { byte[] buffer = new byte[BUFFER_SIZE * 8 / 4]; Arrays.fill(buffer, (byte) 0x00); int rlen = -1; while ((rlen = is.read(buffer)) != -1) { if (rlen % 4 != 0) { throw new IOException("Base64 data stream EOF with error length"); } int asciiSize = rlen / 4 * 3; // 4byte转成3byte byte[] oBuffer = new byte[asciiSize]; // 每次取一个6bit的ascci for (int i = 0; i < asciiSize; i++) { Byte k = getByte628(buffer, i); if (null != k) { oBuffer[i] = k; } } Arrays.fill(buffer, (byte) 0x00); os.write(oBuffer); } } /** * Base64解码-字符串处理，返回byte[] * * @param data * @return */ public static byte[] decode(String data) { StringInputStream sis = new StringInputStream(data); ByteOutputStream bos = new ByteOutputStream(); try { decode(sis, bos); } catch (IOException e) { e.printStackTrace(); } return bos.getBytes(); } /** * Base64解码-字符串处理,返回String * * @param data * @param charset * @return */ public static String decode2String(String data, String charset) { byte[] bs = decode(data); if (charset == null || charset.trim().isEmpty() || !Charset.isSupported(charset)) { return new String(bs); } try { return new String(bs, charset); } catch (UnsupportedEncodingException e) { e.printStackTrace(); return null; } } /** * 从缓存取中取出一个8bit的数据(4byte转成3byte) * * @param buffer * @param index * 8bit的index * @return */ private static Byte getByte628(byte[] buffer, int index) { int group8Count = index / 3; // 3个一组，对应base64的4个一组 int num = index % 3; // 分组中的几号位置(0:1-2,1:2-3,2:3-4) int g6Index = group8Count * 4; if (num == 0) { Byte bs = reMap.get(buffer[g6Index]); Byte be = reMap.get(buffer[g6Index + 1]); if (bs == null) { return null; } if (be == null) { be = 0; } return (byte) ((bs << 2) | (be >> 4)); } else if (num == 1) { Byte bs = reMap.get(buffer[g6Index + 1]); Byte be = reMap.get(buffer[g6Index + 2]); if (bs == null) { return null; } if (be == null) { be = 0; } return (byte) (((bs & 0x0f) << 4) | (be >> 2)); } else { Byte bs = reMap.get(buffer[g6Index + 2]); Byte be = reMap.get(buffer[g6Index + 3]); if (bs == null) { return null; } if (be == null) { be = 0; } return (byte) (((bs & 0x03) << 6) | be); } } /** * 从缓存区中取出一个6bit的数据(3byte转成6byte) * * @param buffer * @param index * 6bit的index * @return */ private static byte getByte826(byte[] buffer, int index) { int startPos = index * 6; int endPos = (index + 1) * 6 - 1; int startAt = startPos / 8; // 在buffer中的位置 byte bs = buffer[startAt]; // 起点所在的字节 int bsi = bs & 0x000000ff; // start8Pos : 0,6,4,2 int start8Pos = startPos % 8; // 在一个字节中的位置 if (start8Pos == 0 || start8Pos == 2) { if (start8Pos == 0) { return (byte) (bsi >> 2); } else { return (byte) (bsi & 0x3f); } } else { int endAt = endPos / 8; byte be = buffer[endAt]; int bei = be & 0x000000ff; if (start8Pos == 6) { int h2 = (bsi & 0x03) << 4; int l4 = bei >> 4; return (byte) (h2 | l4); } else { int h4 = (bsi & 0x0f) << 2; int l2 = bei >> 6; return (byte) (h4 | l2); } } } public static void main(String[] args) throws IOException { String[] paths = new String[]{"F:/base64/file.doc","F:/base64/file.docx","F:/base64/file.png","F:/base64/file.jpg","F:/base64/file.bmp","F:/base64/AotainDamsPortal.war"}; for(String path : paths) { File f = new File(path); if(!f.exists()) { continue; } InputStream is = new FileInputStream(f); FileOutputStream os = new FileOutputStream(path+"_.txt"); long st = System.currentTimeMillis(); encode(is, os); os.close(); is.close(); System.out.println(path+":"+(System.currentTimeMillis() - st)); } for(String path : paths) { File f = new File(path+"_.txt"); if(!f.exists()) { continue; } InputStream is = new FileInputStream(f); FileOutputStream os = new FileOutputStream(path.replace("base64", "base64/decode")); long st = System.currentTimeMillis(); decode(is, os); os.close(); is.close(); System.out.println(path+":"+(System.currentTimeMillis() - st)); } } }