java 字符串转换成十六进制编码和转换十六进制编码为字符串

package test;

public class StringTest {

	public static String toHexString(String s) {
		String str = "";
		for (int i = 0; i < s.length(); i++) {
			int ch = (int) s.charAt(i);
			String s4 = Integer.toHexString(ch);
			str = str + s4;
		}
		return "0x" + str;//0x表示十六进制
	}

	//转换十六进制编码为字符串
	public static String toStringHex(String s) {
		if ("0x".equals(s.substring(0, 2))) {
			s = s.substring(2);
		}
		byte[] baKeyword = new byte[s.length() / 2];
		for (int i = 0; i < baKeyword.length; i++) {
			try {
				baKeyword[i] = (byte) (0xff & Integer.parseInt(s.substring(
						i * 2, i * 2 + 2), 16));
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		try {
			s = new String(baKeyword, "utf-8");//UTF-16le:Not
		} catch (Exception e1) {
			e1.printStackTrace();
		}
		return s;
	}

	public static void main(String[] args) throws Exception {
		String str = "test";
		printHexString(str.getBytes());
	}

	public static void printHexString(byte[] b) {
		for (int i = 0; i < b.length; i++) {
			String hex = Integer.toHexString(b[i] & 0xFF);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			System.out.print(hex.toUpperCase());
		}
	}

}