NSData转化成NSString

NSData*testData = characteristic.value;

Byte*testByte= (Byte*)[testDatabytes];

NSMutableArray*midArray= [NSMutableArrayarray];

for(inti=0;i<[testDatalength];i++){

[midArrayaddObject:[NSStringstringWithFormat:@"%d",testByte[i]]];

}

for(NSString*strinmidArray) {

[_mutStrappendString:str];

[_mutStrappendString:@"/"];

}