java把InputStram 转换为String

public static String readStream(InputStream in) throws Exception{
//定义一个内存输出流
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int len=-1;
Byte[] bytes = new Byte[];
while((len=in.read(bytes))!=-1){
boas.write(bytes,0,len);
}
in.close();
String content = new String(boas.toByteArray());
return content
}