android数据转换tips

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//将int类型转换成byte[]数组类型:

public byte[] intTobyteArr(){

    Integer a= 60855;
       byte[] b = new byte[4];
       b[0] = (byte)(a&0x000000ff);
       b[1] = (byte)((a&0x0000ff00)>>8);
       b[2] = (byte)((a&0x00ff0000)>>16);
       b[3] = (byte)((a&0xff000000)>>24);
           System.out.println(Byte.toString(b[0]));
           System.out.println(Byte.toString(b[1]));
           System.out.println(Byte.toString(b[2]));
           System.out.println(Byte.toString(b[3]));

}

又手残忘记移位了。

//四字节byte转换成long

public static long byte4ArrToLong(byte[] b){
       if(b.length != 4){
           return 0L;
       }
       long ret_l = 0L;
       ret_l+=(b[3]&0xff);
       ret_l+=(b[2]&0xff)<<8;
       ret_l+=(b[1]&0xff)<<16;
       ret_l+=(b[0]&0xff)<<24;

       return ret_l;
}

//四字节逆置转成long
public static long byte4ArrReverseToLong(byte[] b){
    if(b.length != 4){
           return 0L;
       }
       long ret_l = 0L;
       ret_l+=(b[0]&0xff);
       ret_l+=(b[1]&0xff)<<8;
       ret_l+=(b[2]&0xff)<<16;
       ret_l+=(b[3]&0xff)<<24;

       return ret_l;

}

//String转换成byte[]

String s= "abcdeg";

s.getBytes();

//字符转换成asc码

public static int getAsc(String st) {        byte[] gc = st.getBytes();        ascNum = (int) gc[0];        return ascNum;    }

//asc码转字符

public static char backchar(int backnum) {        strChar = (char) backnum;        return strChar;    }

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