关于字符串和byte数组在java和ios之间兼容的解决办法。

之前在java上写过String转为byte数组的代码，后来在开发iPhone程序的时候，发现也需要把NSString转为byte数组，并且需要达到跟java程序兼容。但是发现java自身的默认编码机制为iso-8859-1，而ios的默认编码机制为utf-8，所以直接编码并不能达到两者兼容的问题。后来查阅相关资料，最后解决了编码兼容的问题，而且中英文都通用。

如下为java代码：y

 String str = "你好啊,aBc!";
 ByteArrayOutputStream baos = new ByteArrayOutputStream();
 DataOutputStream outputstream = new DataOutputStream(baos);
 outputstream.writeChars(str);

 byte[] contents = baos.toByteArray();
 for (int i = 0; i < contents.length; i++) {
     System.out.println("contents:"+contents[i]);
 }

最后打印为：

 contents:79
 contents:96
 contents:89
 contents:125
 contents:85
 contents:74
 contents:0
 contents:44
 contents:0
 contents:97
 contents:0
 contents:66
 contents:0
 contents:99
 contents:0
 contents:33

ios代码：

NSString *str = @"你好啊,aBc!";  
NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding
(NSUTF16BigEndianStringEncoding);  
NSData *data = [str dataUsingEncoding:enc];  
Byte *byte = (Byte *)[data bytes];  
for (int i=0 ; i<[data length]; i++) {  
    NSLog(@"byte = %d",byte[i]);  
}

最后打印结果为

 2012-07-19 10:07:46.967 encoding[593:f803] byte = 79
 2012-07-19 10:07:46.969 encoding[593:f803] byte = 96
 2012-07-19 10:07:46.969 encoding[593:f803] byte = 89
 2012-07-19 10:07:46.970 encoding[593:f803] byte = 125
 2012-07-19 10:07:46.970 encoding[593:f803] byte = 85
 2012-07-19 10:07:46.970 encoding[593:f803] byte = 74
 2012-07-19 10:07:46.970 encoding[593:f803] byte = 0
 2012-07-19 10:07:46.971 encoding[593:f803] byte = 44
 2012-07-19 10:07:46.971 encoding[593:f803] byte = 0
 2012-07-19 10:07:46.971 encoding[593:f803] byte = 97
 2012-07-19 10:07:46.971 encoding[593:f803] byte = 0
 2012-07-19 10:07:46.972 encoding[593:f803] byte = 66
 2012-07-19 10:07:46.972 encoding[593:f803] byte = 0
 2012-07-19 10:07:46.972 encoding[593:f803] byte = 99
 2012-07-19 10:07:46.972 encoding[593:f803] byte = 0
 2012-07-19 10:07:46.973 encoding[593:f803] byte = 33

编码达到了一致！