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JVM大端
JVM采用大端方式存多字节的数据，判断方法如下：
1 public static void bytesToInt() throws IOException { 2 /** 3 * 将字节数组（byte[]）转为整形(int) 4 */ 5 byte[] byteAr = new byte[] { 0x78, 0x56, 0x34, 0x12 }; 6 ByteArrayInputStream bais = new ByteArrayInputStream(byteAr); 7 DataInputStream dis = new DataInputStream(bais); 8 System.out.println(Integer.toHexString(dis.readInt()));// output: 78563412，说明是大端 9 }10 11 public static void intToBytes() throws IOException {12 /**13 * 将整形(int)转为字节数组（byte[]）14 */15 int a = 0x12345678;16 ByteArrayOutputStream baos = new ByteArrayOutputStream();17 DataOutputStream dos = new DataOutputStream(baos);18 dos.writeInt(a);19 byte[] b = baos.toByteArray();20 for (int i = 0; i < 4; i++) {21 System.out.print(Integer.toHexString(b[i]));22 }23 System.out.println();// Output: 12345678，说明是大端24 }
采用大小模式对数据进行存放的主要区别在于在存放的字节顺序，大端方式将高位存放在低地址，小端方式将高位存放在高地址。采用大端方式数据存放与阅读顺序一致，符合人类的正常思维，而采用小端方式进行数据存放利于计算机处理。到目前为止，采用大端或者小端进行数据存放，其孰优孰劣也没有定论。
参考资料：
Java‘s Virtual Machine‘s Endianness-StackOverFlow
The Java Virtual Machine Specification, Java SE 7 Edition, Chapter 4: The class File Format
A
classfile consists of a stream of 8-bit bytes. All 16-bit, 32-bit, and 64-bit quantities are constructed by reading in two, four, and eight consecutive 8-bit bytes, respectively. Multibyte data items are always stored in big-endian order, where the high bytes come first. In the Java SE platform, this format is supported by interfacesjava.io.DataInputandjava.io.DataOutputand classes such asjava.io.DataInputStreamandjava.io.DataOutputStream.
JVM大端