转化为字节流

最新推荐文章于 2020-07-30 09:19:54 发布

最新推荐文章于 2020-07-30 09:19:54 发布 · 275 阅读

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本文介绍了一个Java工具类，该类提供了将各种基本数据类型（如long、int、float等）与byte数组互相转换的方法。这些方法对于网络通信、文件读写等场景非常有用。


package eccl.socket.tools;

public class ByteOperator{

	public ByteOperator(){

	}


	/**   
	*   长整形转化为byte类型  
	*/ 
	public static void putLong(byte[] buf,int offset,long value) { 
        buf[offset + 0] = (byte) ((value >> 56) & 0xff); 
        buf[offset + 1] = (byte) ((value >> 48) & 0xff); 
        buf[offset + 2] = (byte) ((value >> 40) & 0xff); 
        buf[offset + 3] = (byte) ((value >> 32) & 0xff); 
        buf[offset + 4] = (byte) ((value >> 24) & 0xff); 
        buf[offset + 5] = (byte) ((value >> 16) & 0xff); 
        buf[offset + 6] = (byte) ((value >> 8) & 0xff); 
        buf[offset + 7] = (byte) ((value >> 0) & 0xff); 
    } 


    /**
     * byte 型转化为 Long 类型
     */

    public static long getLong(byte[] bytes, int index) { 
        return ((((long) bytes[index + 0] & 0xff) << 56) 
                | (((long) bytes[index + 1] & 0xff) << 48) 
                | (((long) bytes[index + 2] & 0xff) << 40) 
                | (((long) bytes[index + 3] & 0xff) << 32) 
                | (((long) bytes[index + 4] & 0xff) << 24) 
                | (((long) bytes[index + 5] & 0xff) << 16) 
                | (((long) bytes[index + 6] & 0xff) << 8) | (((long) bytes[index + 7] & 0xff) << 0)); 
    } 


	/**   
	*   整形转化为byte类型  
	*/   
	public static void putInt(byte[] buf,int offset,int value)   {   
		buf[offset+0] = (byte)((value  >> 24) & 0xff);   
		buf[offset+1] = (byte)((value  >> 16) & 0xff);   
		buf[offset+2] = (byte)((value  >> 8)  & 0xff);   
		buf[offset+3] = (byte)((value  >> 0)  & 0xff);   
	}

	/**
     *  byte类型转换为int型
     */

    public static int getInt(byte[] bytes, int index) { 
        return (int) ((((bytes[index + 0] & 0xff) << 24) | ((bytes[index + 1] & 0xff) << 16) | ((bytes[index + 2] & 0xff) << 8) | ((bytes[index + 3] & 0xff) << 0))); 
    } 	


	/**
     *  浮点型转化为byte类型
     */

	public static void putFloat(byte[] buf,int offset,float value){

		try {
			putInt(buf,offset,Float.floatToIntBits(value));
	    }
	    catch (Exception ex) {
	    	System.out.print("convert the float to Byte is error!\n");
	    }

	}

	/**
     *  byte类型转换为浮点型
     */

     public static float getFloat(byte[] bytes,int index){

	    int num = ((bytes[index]<<24)&0xFF000000)|((bytes[index+1]<<16)&0xFF0000)|((bytes[index+2]<<8)&0xFF00)|(bytes[index+3]&0xFF);
	    float f = Float.intBitsToFloat(num);
		return f;
     }


	/**
     *  byte 类型转换为 short型
     */

    public static short getShort(byte[] bytes, int index) { 
        return (short) (((bytes[index] << 8) | bytes[index + 1] & 0xff)); 
    }	


   /**   
	*   短整形转化为byte类型  
	*/   
	public static void putShort(byte[] buf,int offset,short value)   {   
		buf[offset+0] = (byte)((value  >> 8) & 0xff);   
		buf[offset+1] = (byte)((value  >> 0) & 0xff);
	}	


	/**   
	*   字符串转化为byte类型  
	*/ 
	public static void putStr(byte[] buf,int offset,int length,String value) {
		try{
			byte[] tmpByte = value.getBytes();
			for(int i=length-1;i>=0;i--){
//				buf[offset+i] = tmpByte[i];	
				buf[offset+i] = tmpByte[i];	
			}
		}catch(Exception e)
		{
			System.out.print("convert the String to Byte is error!\n"+e);
		}
	}	


	/**
     * byte型转换为字符串型
     */

     public static String getStr(byte[] bytes,int index){

     	byte[] str = new byte[4];
     	for(int i=0;i<4;i++){
     		str[i] = bytes[index+i];	
     	}

		return new String(str);

     }	

}