使用java rsa 签名和验签，生成私钥和公钥

package com.twodfire.alipay.utils;


import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Map;
import java.util.SortedMap;

/**
 * Created by Administrator on 2015/12/25.
 */
public class RsaCipherHelper {
    private static final String GOUQI_PRIVATE_KEY = "MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBAIodOSS4fXlvWYrgJdOCeLhBCsei" +
            "CBaYqolfdViVCIETXJWQovUf1qRUtFyUaO4uh/2I0zx125MWA/Nr8Lz3iRSm2MfA62aON019Qsl8" +
            "iAztT3a3Qe9duavhrNqyILX+QMyOIuHHHObD0ChbgsuBINrJ2OttDH+LP7Wss3kO4eMdAgMBAAEC" +
            "gYAUmIkF9dEYQ8eZkxVw9hrkdyaRYJNOM1PzCl4oaIkNHoMG9rumTCoo9Uy0JZmEM0IqR7YgZP7q" +
            "bzUFnsoWk99IESL98WnEZg+ze7xQdv0fwPA1c43MhzD+i1a0LWPS10HlO+M7PfQyWWguHa3os+aQ" +
            "DSyYrHg6M+e6tkh4X7yf7QJBAODPtGe0F7XtXKVwvO+lnEzYw7mKhEsB6Rtz/bV/AVRsmT4ahnnb" +
            "dCFvyyInEZ56faJyxjVhdB85TZ29ESHl9VcCQQCdRmvZePTlpT2vxjQswtRtOlzekIRgm19vgu2X" +
            "foUyVgISiqvl0+uPHAju9wYkkyNm001l9OVU5uo+0LiMHc6rAkAL28j3Y2+QwCmP7Id62LCK+TAx" +
            "3FWoIzypnw+2ADIQwv2+YeXQDbxtexkq/waV5n40EHvWGwLmFr66YFvD/v5XAkA2CneOf2Bu9Etw" +
            "9YMCCmQhsBcvJqtF4r11PKDVGFU+SY1mv513WE0tnG15ZwoGUUSt1VdX/EE822fT87Yl9ywHAkBG" +
            "7hb76FMfc9dXXxMSxeP+HVk0M6BW0GCNZWp2xE6yYxLvesy1IeLUOrsHjhd6JhvUc0+Ym91F7kNn" +
            "aXqPCDRd";

    private static final String GOUQI_PUBLIC_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCKHTkkuH15b1mK4CXTgni4QQrHoggWmKqJX3VY" +
            "lQiBE1yVkKL1H9akVLRclGjuLof9iNM8dduTFgPza/C894kUptjHwOtmjjdNfULJfIgM7U92t0Hv" +
            "Xbmr4azasiC1/kDMjiLhxxzmw9AoW4LLgSDaydjrbQx/iz+1rLN5DuHjHQIDAQAB";

    /**
     * 生成签名
     *
     * @param content
     * @param privateKey
     * @return
     */
    public static String sign(String content, String privateKey) {
        return sign(content, str2PrivateKey(privateKey));
    }

    /**
     * 验证签名
     *
     * @param content
     * @param publicKey
     * @return
     */
    public static boolean verify(String content, String sign, String publicKey) {
        return verify(content, sign, str2PublicKey(publicKey));
    }

    /**
     * @param content
     * @param privateKey
     * @return
     */
    public static String sign(String content, RSAPrivateKey privateKey) {
        try {
            Signature signature = Signature.getInstance("SHA1withRSA");
            signature.initSign(privateKey);
            signature.update(content.getBytes("utf-8"));
            return new BASE64Encoder().encode(signature.sign());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * @param content
     * @param publicKey
     * @return
     */
    public static boolean verify(String content, String sign, RSAPublicKey publicKey) {
        try {
            Signature signature = Signature.getInstance("SHA1withRSA");
            signature.initVerify(publicKey);
            signature.update(content.getBytes("utf-8"));
            return signature.verify((new BASE64Decoder()).decodeBuffer(sign));
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static RSAPublicKey str2PublicKey(String publicKeyPerm) {
        try {
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec((new BASE64Decoder()).decodeBuffer(publicKeyPerm));
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            return (RSAPublicKey) keyFactory.generatePublic(keySpec);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static RSAPrivateKey str2PrivateKey(String privateKeyPerm) {
        try {
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec((new BASE64Decoder()).decodeBuffer(privateKeyPerm));
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 将所有POST 参数（sign除外）进行字典排序，组成字符串, 然后使用私钥产生签名
     * @param params
     * @return sign
     */
    public static String encodeParams(SortedMap<?, ?> params, String privateKey) {
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<?, ?> entry : params.entrySet()) {
            sb.append(entry.getKey())
                    .append("=")
                    .append(entry.getValue())
                    .append("&");
        }

        sb.deleteCharAt(sb.length() - 1);
        return sign(sb.toString(), privateKey);
    }

    public static void main2(String[] args) throws Exception {

        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(1024);
        KeyPair keyPair = keyPairGenerator.genKeyPair();
        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();

        BASE64Encoder base64Encoder = new BASE64Encoder();
        System.out.println("-------------------public key----------------------");
        System.out.println(base64Encoder.encode(publicKey.getEncoded()));
        System.out.println("-------------------private key---------------------");
        System.out.println(base64Encoder.encode(privateKey.getEncoded()));

    }

    public static void main3(String[] args) {
        String publicKey = GOUQI_PUBLIC_KEY;
        String privateKey = GOUQI_PRIVATE_KEY;

        String appPrivateKey = "MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAN0yqP" +
                "kLXlnhM+2H/57aHsYHaHXazr9pFQun907TMvmbR04wHChVsKVgGUF1hC0FN" +
                "9hfeYT5v2SXg1WJSg2tSgk7F29SpsF0I36oSLCIszxdu7ClO7c22mxEVuCj" +
                "mYpJdqb6XweAZzv4Is661jXP4PdrCTHRdVTU5zR9xUByiLSVAgMBAAECgYEAh" +
                "znORRonHylm9oKaygEsqQGkYdBXbnsOS6busLi6xA+iovEUdbAVIrTCG9t854" +
                "z2HAgaISoRUKyztJoOtJfI1wJaQU+XL+U3JIh4jmNx/k5UzJijfvfpT7Cv3ueM" +
                "tqyAGBJrkLvXjiS7O5ylaCGuB0Qz711bWGkRrVoosPM3N6ECQQD8hVQUgnHEVH" +
                "ZYtvFqfcoq2g/onPbSqyjdrRu35a7PvgDAZx69Mr/XggGNTgT3jJn7+2XmiGkH" +
                "M1fd1Ob/3uAdAkEA4D7aE3ZgXG/PQqlm3VbE/+4MvNl8xhjqOkByBOY2ZFfWKh" +
                "lRziLEPSSAh16xEJ79WgY9iti+guLRAMravGrs2QJBAOmKWYeaWKNNxiIoF7/4" +
                "VDgrcpkcSf3uRB44UjFSn8kLnWBUPo6WV+x1FQBdjqRviZ4NFGIP+KqrJnFHzN" +
                "gJhVUCQFzCAukMDV4PLfeQJSmna8PFz2UKva8fvTutTryyEYu+PauaX5laDjyQ" +
                "bc4RIEMU0Q29CRX3BA8WDYg7YPGRdTkCQQCG+pjU2FB17ZLuKRlKEdtXNV6zQ" +
                "FTmFc1TKhlsDTtCkWs/xwkoCfZKstuV3Uc5J4BNJDkQOGm38pDRPcUDUh2/";

        String sign = sign("jackiezhi", appPrivateKey);
        System.out.println(sign);
        //System.out.println(verify("jackiezhi", sign, publicKey));


    }

}