package sci.utils;/** * 仅仅适用于 Java 与 C 通讯中，网络流解析与生成使用 * * 高低位互换(Big-Endian 大头在前 & Little-Endian 小头在前)。 * 举例而言，有一个4字节的数据0x01020304，要存储在内存中或文件中编号0˜3字节的位置，两种字节序的排列方式分别如下： * <pre> * Big Endian * * 低地址 高地址 * ----------------------------------------------------> * 地址编号 * | 0 | 1 | 2 | 3 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | 01 | 02 | 03 | 04 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Little Endian * * 低地址 高地址 * ----------------------------------------------------> * 地址编号 * | 0 | 1 | 2 | 3 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | 04 | 03 | 02 | 01 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * </pre> * Java则统一使用big模式 * c中的unsigned short 对应着java中的char两个字节，无符号 * c的无符号int,short,byte字节数组，相应转换成java的long,char,short * * @author Snowolf * @version 1.0 * @since 1.0 */import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;public abstract class CIOUtil {public static final String CHARSET = "UTF-8";/** * 从输入流中读布尔 * * @param is * @return * @throws IOException */public static boolean readBoolean(DataInputStream is) throws IOException {return is.readBoolean();}/** * 从流中读定长度字节数组 * * @param is * @param s * @return * @throws IOException */public static byte[] readBytes(DataInputStream is, int i)throws IOException {byte[] data = new byte[i];is.readFully(data);return data;}/** * 从输入流中读字符 * * @param is * @return * @throws IOException */public static char readChar(DataInputStream is) throws IOException {return (char) readShort(is);}/** * 从输入流中读双精度 * * @param is * @return * @throws IOException */public static double readDouble(DataInputStream is) throws IOException {return Double.longBitsToDouble(readLong(is));}/** * 从输入流中读单精度 * * @param is * @return * @throws IOException */public static float readFloat(DataInputStream is) throws IOException {return Float.intBitsToFloat(readInt(is));}/** * 从流中读整型 * * @param is * @return * @throws IOException */public static int readInt(DataInputStream is) throws IOException {return Integer.reverseBytes(is.readInt());}/** * 从流中读长整型 * * @param is * @return * @throws IOException */public static long readLong(DataInputStream is) throws IOException {return Long.reverseBytes(is.readLong());}/** * 从流中读短整型 * * @param is * @return * @throws IOException */public static short readShort(DataInputStream is) throws IOException {return Short.reverseBytes(is.readShort());}/** * 从输入流中读字符串 字符串 结构 为 一个指定字符串字节长度的短整型+实际字符串 * * @param is * @return * @throws IOException */public static String readUTF(DataInputStream is) throws IOException {short s = readShort(is);byte[] str = new byte[s];is.readFully(str);return new String(str, CHARSET);}/** * 向输出流中写布尔 * * @param os * @param b * @throws IOException */public static void writeBoolean(DataOutputStream os, boolean b)throws IOException {os.writeBoolean(b);}/** * 向输出流中写字节数组 * * @param os * @param data * @throws IOException */public static void writeBytes(DataOutputStream os, byte[] data)throws IOException {os.write(data);}/** * 向输出流中写字符 * * @param os * @param b * @throws IOException */public static void writeChar(DataOutputStream os, char b)throws IOException {writeShort(os, (short) b);}/** * 向输出流中写双精度 * * @param os * @param d * @throws IOException */public static void writeDouble(DataOutputStream os, double d)throws IOException {writeLong(os, Double.doubleToLongBits(d));}/** * 向输出流中写单精度 * * @param os * @param f * @throws IOException */public static void writeFloat(DataOutputStream os, float f)throws IOException {writeInt(os, Float.floatToIntBits(f));}/** * 向输出流中写整型 * * @param os * @param i * @throws IOException */public static void writeInt(DataOutputStream os, int i) throws IOException {os.writeInt(Integer.reverseBytes(i));}/** * 向输出流中写长整型 * * @param os * @param l * @throws IOException */public static void writeLong(DataOutputStream os, long l)throws IOException {os.writeLong(Long.reverseBytes(l));}/** * 向输出流中写短整型 * * @param os * @param s * @throws IOException */public static void writeShort(DataOutputStream os, short s)throws IOException {os.writeShort(Short.reverseBytes(s));}/** * 向输出流中写字符串 字符串 结构 为 一个指定字符串字节长度的短整型+实际字符串 * * @param os * @param str * @throws IOException */public static void writeUTF(DataOutputStream os, String str)throws IOException {byte[] data = str.getBytes(CHARSET);writeShort(os, (short) data.length);os.write(data);}}// 上面的测试
package test;import static org.junit.Assert.assertArrayEquals;import static org.junit.Assert.assertEquals;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;import org.junit.Test;import sci.utils.CIOUtil;public class CIOUtilTest {/** * 测试布尔值 * * @throws IOException */@Testpublic final void testBoolean() throws IOException {boolean input = true;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeBoolean(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);boolean output = CIOUtil.readBoolean(is);bais.close();assertEquals(input, output);}/** * 测试字节数组 * * @throws IOException */@Testpublic final void testBytes() throws IOException {byte[] input = "中文".getBytes("UTF-8");ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeBytes(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);byte[] output = CIOUtil.readBytes(is, 6);bais.close();assertArrayEquals(input, output);}/** * 测试字符 * * @throws IOException */@Testpublic final void testChar() throws IOException {char input = '中';ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeChar(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);char output = CIOUtil.readChar(is);bais.close();assertEquals(input, output);}/** * 测试双精度 * * @throws IOException */@Testpublic final void testDouble() throws IOException {double input = 1.23456789d;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeDouble(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);double output = CIOUtil.readDouble(is);bais.close();assertEquals(input, output, 9);}/** * 测试单精度 * * @throws IOException */@Testpublic final void testFloat() throws IOException {float input = 1.23456789f;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeFloat(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);float output = CIOUtil.readFloat(is);bais.close();assertEquals(input, output, 9);}/** * 测试整型 * * @throws IOException */@Testpublic final void testInt() throws IOException {int input = 1;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeInt(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);int output = CIOUtil.readInt(is);bais.close();assertEquals(input, output);}/** * 测试长整型 * * @throws IOException */@Testpublic final void testLong() throws IOException {long input = 1l;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeLong(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);long output = CIOUtil.readLong(is);bais.close();assertEquals(input, output);}/** * 测试短整型 * * @throws IOException */@Testpublic final void testShort() throws IOException {short input = 1;ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeShort(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);short output = CIOUtil.readShort(is);bais.close();assertEquals(input, output);}/** * 测试UTF-8字符串 * * @throws IOException */@Testpublic final void testUTF() throws IOException {String input = "中文支持";ByteArrayOutputStream baos = new ByteArrayOutputStream();DataOutputStream os = new DataOutputStream(baos);CIOUtil.writeUTF(os, input);byte[] b = baos.toByteArray();baos.flush();baos.close();ByteArrayInputStream bais = new ByteArrayInputStream(b);DataInputStream is = new DataInputStream(bais);String output = CIOUtil.readUTF(is);bais.close();assertEquals(input, output);}}
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