总结一下与字节数组相关的IO操作。
关于 把十六进制的位串转化为byte数组，请参阅 http://hw1287789687.iteye.com/blog/1882644
（1）从InputStream 读取字节数组
方式一：
Java代码
- /***
- * Has been tested
- *
- * @param in
- * @return
- * @throws IOException
- */
- public static byte[] readBytes3(InputStream in) throws IOException {
- BufferedInputStream bufin = new BufferedInputStream(in);
- int buffSize = BUFFSIZE_1024;
- ByteArrayOutputStream out = new ByteArrayOutputStream(buffSize);
- // System.out.println("Available bytes:" + in.available());
- byte[] temp = new byte[4096];
- int size = 0;
- while ((size = bufin.read(temp)) != -1) {
- out.write(temp, 0, size);
- }
- bufin.close();
- in.close();
- byte[] content = out.toByteArray();
- return content;
- }
说明：先把inputstream的字节读到ByteArrayOutputStream中，读完之后再调用toByteArray() 转化为字节数组。
方式二：
Java代码
- /***
- * Has been tested
- *
- * @param in
- * @return
- * @throws IOException
- */
- public static byte[] readBytes(InputStream in) throws IOException {
- byte[] temp = new byte[in.available()];
- byte[] result = new byte[0];
- int size = 0;
- while ((size = in.read(temp)) != -1) {
- byte[] readBytes = new byte[size];
- System.arraycopy(temp, 0, readBytes, 0, size);
- result = mergeArray(result, readBytes);
- }
- return result;
- }
- /***
- * 合并字节数组
- *
- * @param a
- * @return
- */
- public static byte[] mergeArray(byte[]... a) {
- // 合并完之后数组的总长度
- int index = 0;
- int sum = 0;
- for (int i = 0; i < a.length; i++) {
- sum = sum + a[i].length;
- }
- byte[] result = new byte[sum];
- for (int i = 0; i < a.length; i++) {
- int lengthOne = a[i].length;
- if (lengthOne == 0) {
- continue;
- }
- // 拷贝数组
- System.arraycopy(a[i], 0, result, index, lengthOne);
- index = index + lengthOne;
- }
- return result;
- }
（2）把字节数组写入文件
Java代码
- /***
- * write byte[] to file
- *
- * @param bytes
- * @param destFile
- * @throws IOException
- */
- public static void writeBytesToFile(byte[] bytes, File destFile)
- throws IOException {
- FileOutputStream out = new FileOutputStream(destFile);
- write2File(bytes, out);
- }
- /***
- *
- * @param bytes
- * @param out
- * @throws IOException
- */
- public static void write2File(byte[] bytes, FileOutputStream out)
- throws IOException {
- out.write(bytes);
- out.close();
- }
（3）在已有字节数组基础上追加一个字节
Java代码
- /***
- * append a byte.
- *
- * @param a
- * @param b
- * @return
- */
- public static byte[] appandByte(byte[] a, byte b) {
- int length = a.length;
- byte[] resultBytes = new byte[length + 1];
- System.arraycopy(a, 0, resultBytes, 0, length);
- resultBytes[length] = b;
- return resultBytes;
- }
（4）比较两个字节数组是否相同
Java代码
- /***
- * Compare two byte arrays whether are the same.
- *
- * @param a
- * @param b
- * @return
- */
- public static boolean arrayIsEqual(byte[] a, byte[] b) {
- if(a==null&&b==null){
- return true;
- }
- if (a != null && b != null) {
- if (a.length != b.length) {
- return false;
- } else {
- for (int i = 0; i < a.length; i++) {
- if (a[i] != b[i]) {
- return false;
- }
- }
- }
- }else {//one is null, the other is not null
- return false;
- }
- return true;
- }
（5）查找指定字节findTarget在指定字节数组source中的位置
Java代码
- /***
- *
- * @param source
- * @param findTarget
- * :key word
- * @param pos
- * :where start from
- * @return index
- */
- public static int findBytes(byte[] source, byte[] findTarget, int pos) {
- int i, j, k = 0;
- i = pos;
- j = 0;
- while (i < source.length && j < findTarget.length) {
- if (source[i] == findTarget[j]) {
- ++i;
- ++j;
- if (j == findTarget.length) {
- k = k + 1;// k++
- break;
- // j = 0;
- }
- } else {
- i = i - j + 1;
- j = 0;
- }
- }
- return k == 0 ? -1 : i - j;
- }
测试代码：
Java代码
- @Test
- public void test_arrayIsEqual2(){
- System.out.println("test_filterFrontBytes");
- byte[] a = new byte[] { 1, 2, 3, 4 };
- byte[] b = new byte[] { 1, 2, 3 };
- System.out.println( <span style="font-size: 1em; line-height: 1.5;">arrayIsEqual</span><span style="font-size: 1em; line-height: 1.5;">(a, b));</span>
Java代码
- }
- @Test
- public void test_appandByte(){
- byte[]bytes=new byte[]{1,2,3};
- byte[]resultBytes=appandByte(bytes, (byte)32);
- <span style="font-size: 1em; line-height: 1.5;">arrayIsEqual</span><span style="font-size: 1em; line-height: 1.5;">(resultBytes, new byte[]{1, 2, 3, 32});</span>
Java代码
- }
