16进制int转16进制String
int a = 0x1f601; //16进制int(打印无法显示16进制而是10进制：128513)
String b = Integer.toHexString(a); //(b打印显示为1f601).
10进制int转16进制String
int a = 128513;
String b = Integer.toHexString(a); //(b打印显示为1f601).
16进制string转换成10进制int
int x = Integer.parseInt("1f601", 16); //x为128513
16进制int转unicode编码
int a = 0x1f601;
int b[] = {a};
String unicode = new String(b, 0, b.length); // unicode = "\ud83d\ude01"
