django 默认密码加密算法pbkdf2-sha256如何用java实现？

package main

import (
    "crypto/sha256"
    "encoding/base64"
    "strconv"
 "crypto/hmac"
 "hash"
 "io"
    "net/http"
 "strings"
 "math/rand"
 "time"
 "fmt"
)

// djnago 的实现细节请参考 Python 和 djnago 文档：
// djnago.contrib.auth.hashers.make_password
// djnago.utils.crypto import pbkdf2
// hashlib.sha256
// base64
func main() {
 http.HandleFunc("/djnagopwd", gendjnagopwd)
 http.ListenAndServe(":7070", nil)
}

func gendjnagopwd(rw http.ResponseWriter, req *http.Request){
 req.ParseForm();
 attempted := req.FormValue("attempted");
 var temp = req.FormValue("salt");
 var salt []byte
 if temp != ""{
  salt = []byte (temp)  // 盐，是一个随机字符串，每一个用户都不一样
 }else{
  salt = []byte(genSalt())
 }
 fmt.Println("-----------------salt:::::  "+salt+"  ----------------");
 pwd := []byte(attempted) // 用户设置的原始密码
    iterations := 15000             // 加密算法的迭代次数，15000 次
    digest := sha256.New            // digest 算法，使用 sha256

    // 第一步：使用 pbkdf2 算法加密
    dk := Key(pwd, salt, iterations, 32, digest)

    // 第二步：Base64 
    str := base64.StdEncoding.EncodeToString(dk)
 // 第三步：组合加密算法、迭代次数、盐、密码和分割符号 "$"
 io.WriteString(rw, "pbkdf2_sha256" + "$" + strconv.FormatInt(int64(iterations), 10) + "$" + string(salt) + "$" + str);
}

func Key(password, salt []byte, iter, keyLen int, h func() hash.Hash) []byte {
 prf := hmac.New(h, password)
 hashLen := prf.Size()
 numBlocks := (keyLen + hashLen - 1) / hashLen

 var buf byte
 dk := make([]byte, 0, numBlocks*hashLen)
 U := make([]byte, hashLen)
 for block := 1; block <= numBlocks; block++ {
  // N.B.: || means concatenation, ^ means XOR
  // for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
  // U_1 = PRF(password, salt || uint(i))
  prf.Reset()
  prf.Write(salt)
  buf = byte(block >> 24)
  buf = byte(block >> 16)
  buf = byte(block >> 8)
  buf = byte(block)
  prf.Write(buf[:4])
  dk = prf.Sum(dk)
  T := dk[len(dk)-hashLen:]
  copy(U, T)

  // U_n = PRF(password, U_(n-1))
  for n := 2; n <= iter; n++ {
   prf.Reset()
   prf.Write(U)
   U = U[:0]
   U = prf.Sum(U)
   for x := range U {
    T[x] ^= U[x]
   }
  }
 }
 return dk[:keyLen]
}
/**
*生成随机字符
**/
func genSalt() string {
 length := 12
    rand.Seed(time.Now().UnixNano())
    rs := make([]string, length)
    for start := 0; start < length; start++ {
        t := rand.Intn(3)
        if t == 0 {
            rs = append(rs, strconv.Itoa(rand.Intn(10)))
        } else if t == 1 {
            rs = append(rs, string(rand.Intn(26)+65))
        } else {
            rs = append(rs, string(rand.Intn(26)+97))
        }
    }
    return strings.Join(rs, "")
}

已解决，网上找了几个语言的pbkdf2_sha256算法，计算出的结果都和python不一样。

试过php/java/nodejs/golang，最后只有golang结果和python一致，无奈只有用golang生成密码，java调用golang的http服务，下面贴出代码：