MD5加密用法实现

1.实例化信息摘要器，注意参数为md5，表示md5类型

2.利用digest方法做信息摘要，返回值保存到byte[]数组

3.遍历byte数组，和0xff取与，并转换为hexString，如果其长度小于等于1，则在其前面添加0，append hexString,如此往复

最终得到md5加密结果

4.最终输出结果为：e10adc3949ba59abbe56e057f20f883e

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

public class Demo {
    public static void main(String[] args) throws NoSuchAlgorithmException {
    	//信息摘要器
		MessageDigest messageDigest = MessageDigest.getInstance("md5");
		String pwdString = "123456";
		byte[] bytes = messageDigest.digest(pwdString.getBytes());
		System.out.println(Arrays.toString(bytes));
		StringBuffer stringBuffer = new StringBuffer();
		for(byte b: bytes){
			int number = b & 0xff;
			String hex = Integer.toHexString(number);
			if(hex.length() <= 1){
				stringBuffer.append('0');
			}
			stringBuffer.append(hex);
		}
		System.out.println(stringBuffer);
	} 
}