数据结构与算法-hash(哈希)

通过哈希算法可以实现布隆过滤器, 一致性哈希，解决工程中的问题。

import javax.xml.bind.DatatypeConverter;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
import java.util.Locale;

public class Code_Hash {
    private MessageDigest hash;


       public Code_Hash(String algorithm){
            try {
                hash = MessageDigest.getInstance(algorithm);
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
        }

        public String hashCode(String input){
            return DatatypeConverter.printHexBinary(hash.digest(input.getBytes())).toUpperCase();
        }


    public static void main(String[] args) {
        System.out.println("支持的算法");
        for (String str: Security.getAlgorithms("MessageDigest")) {
            System.out.println(str);
        }

        String algorithm = "MD5";
        Code_Hash hash = new Code_Hash(algorithm);
        String input1 = "heikediguo1";
        String input2 = "heikediguo2";
        String input3 = "heikediguo3";
        String input4 = "heikediguo4";
        String input5 = "heikediguo5";
        System.out.println(hash.hashCode(input1));
        System.out.println(hash.hashCode(input2));
        System.out.println(hash.hashCode(input3));
        System.out.println(hash.hashCode(input4));
        System.out.println(hash.hashCode(input5));

    }
}