總結一下與位元組數組相關的io操作。
關于 把十六進制的位串轉化為byte數組,請參閱 http://hw1287789687.iteye.com/blog/1882644
(1)從inputstream 讀取位元組數組
方式一:
/***
* 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;
}
說明:先把inputstream的位元組讀到bytearrayoutputstream中,讀完之後再調用tobytearray() 轉化為位元組數組。
方式二:
public static byte[] readbytes(inputstream in) throws ioexception {
byte[] temp = new byte[in.available()];
byte[] result = new byte[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;
* 合并位元組數組
* @param a
public static byte[] mergearray(byte[]... a) {
// 合并完之後數組的總長度
int index = 0;
int sum = 0;
for (int i = 0; i < a.length; i++) {
sum = sum + a[i].length;
byte[] result = new byte[sum];
int lengthone = a[i].length;
if (lengthone == 0) {
continue;
}
// 拷貝數組
system.arraycopy(a[i], 0, result, index, lengthone);
index = index + lengthone;
(2)把位元組數組寫入檔案
* write byte[] to file
* @param bytes
* @param destfile
public static void writebytestofile(byte[] bytes, file destfile)
throws ioexception {
fileoutputstream out = new fileoutputstream(destfile);
write2file(bytes, out);
* @param out
public static void write2file(byte[] bytes, fileoutputstream out)
out.write(bytes);
out.close();
(3)在已有位元組數組基礎上追加一個位元組
* append a byte.
* @param b
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)比較兩個位元組數組是否相同
* compare two byte arrays whether are the same.
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)查找指定位元組findtarget在指定位元組數組source中的位置
* @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;
i = i - j + 1;
j = 0;
return k == 0 ? -1 : i - j;
測試代碼:
@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>
}
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>
}