InputStream is = context.getResources().openRawResource(R.raw.json);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();

String str = "";
try {
str = br.readLine();
while(str != null)
{
sb.append(str);
str = br.readLine();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
response = sb.toString();

由于Java是用UNICODE编码，一个中文占两个字节，inputstream读取的是字节流，所以当然会乱码。换成下面一种方法就可以了。

InputStream is = context.getResources().openRawResource(R.raw.json);
ByteArrayBuffer bb = new ByteArrayBuffer(500);
int current=0;
String str = "";
try {
while((current = is.read())!=-1)
{
bb.append(current);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
response = EncodingUtils.getString(bb.toByteArray(),"GB2312");

测试代码，命名很不规范，请见谅。代码，由于不了解输入输出流，只能按自己的理解，就是inputstream文件读入一个输入流，并用current记录字节数，然后BtyeArrayBuffer::append(int)从输入流获取刚才读取的字节流，再按GB2312编码。得到中文String.