项目结构：

总体代码：

package VirtualUtils;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.Random;
public class CryptoUtils {private static final String ENCODE="utf-8";private static final String ALGORITHM="AES";private static final String PATTERN="AES/ECB/PKCS5PADDING";private static final String ALLCHAR="0123456789qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFDSAZXCVBNM";public static String GenerateKey(){StringBuffer buffer=new StringBuffer();Random random=new Random();for (int i = 0; i < 16; i++) {buffer.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));}return buffer.toString();}public static int GenerateIntKey(){Random random=new Random();return random.nextInt(999999999);}public static String encrypt_msg(String txt,String key) throws Exception {SecretKey secretKey=new SecretKeySpec(key.getBytes(ENCODE),ALGORITHM);Cipher cipher=Cipher.getInstance(PATTERN);cipher.init(Cipher.ENCRYPT_MODE,secretKey);byte[] encrypt_data= cipher.doFinal(txt.getBytes(ENCODE));return Base64.getEncoder().encodeToString(encrypt_data);}public static String decrypt_msg(String txt,String key) throws Exception {SecretKey secretKey=new SecretKeySpec(key.getBytes(ENCODE),ALGORITHM);Cipher cipher=Cipher.getInstance(PATTERN);cipher.init(Cipher.DECRYPT_MODE,secretKey);byte[] decrypt_data= cipher.doFinal(Base64.getDecoder().decode(txt));return new String(decrypt_data, ENCODE);}public static byte[] Encrypt_MD5(byte[]data) throws NoSuchAlgorithmException {MessageDigest digest=MessageDigest.getInstance("MD5");digest.update(data);return digest.digest();}public static byte[] Encrypt_SHA(byte[]data) throws NoSuchAlgorithmException {MessageDigest digest=MessageDigest.getInstance("SHA");digest.update(data);return digest.digest();}public static KeyPairGenerator generator;public static KeyPair keyPair;public static final class keystore{public byte[] public_key;public byte[] private_key;}static {try {generator=KeyPairGenerator.getInstance("RSA");generator.initialize(2048);keyPair=generator.generateKeyPair();}catch (Exception err){err.printStackTrace();}}public static keystore get_key_pair(){keystore key_value=new keystore();key_value.public_key=keyPair.getPublic().getEncoded();key_value.private_key=keyPair.getPrivate().getEncoded();return key_value;}public static byte[] encrypt_data_by_public(byte[] msg, byte[] key) throws Exception {KeyFactory keyFactory=KeyFactory.getInstance("RSA");X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(key);PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.ENCRYPT_MODE,publicKey);return cipher.doFinal(msg);}public static byte[] decrypt_data_by_private(byte[] msg, byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(key);PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.DECRYPT_MODE,privateKey);return cipher.doFinal(msg);}public static byte[] encrypt_data_by_private(byte[] msg, byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(key);PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.ENCRYPT_MODE,privateKey);return cipher.doFinal(msg);}public static byte[] decrypt_data_by_public(byte[] msg,byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(key);PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.DECRYPT_MODE,publicKey);return cipher.doFinal(msg);}public static String Base64ToString(byte[]data){return Base64.getEncoder().encodeToString(data);}public static String BytesToString(byte[]data,String encode) throws UnsupportedEncodingException {return new String(data,encode);}
}

代码组成：

单向加密：sha散列加密

public static byte[] Encrypt_SHA(byte[]data) throws NoSuchAlgorithmException {MessageDigest digest=MessageDigest.getInstance("SHA");digest.update(data);return digest.digest();}

单向加密：md5散列加密

public static byte[] Encrypt_MD5(byte[]data) throws NoSuchAlgorithmException {MessageDigest digest=MessageDigest.getInstance("MD5");digest.update(data);return digest.digest();}

对称加密：AES加密

private static final String ENCODE="utf-8";private static final String ALGORITHM="AES";private static final String PATTERN="AES/ECB/PKCS5PADDING";private static final String ALLCHAR="0123456789qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFDSAZXCVBNM";
public static String encrypt_msg(String txt,String key) throws Exception {SecretKey secretKey=new SecretKeySpec(key.getBytes(ENCODE),ALGORITHM);Cipher cipher=Cipher.getInstance(PATTERN);cipher.init(Cipher.ENCRYPT_MODE,secretKey);byte[] encrypt_data= cipher.doFinal(txt.getBytes(ENCODE));return Base64.getEncoder().encodeToString(encrypt_data);}public static String decrypt_msg(String txt,String key) throws Exception {SecretKey secretKey=new SecretKeySpec(key.getBytes(ENCODE),ALGORITHM);Cipher cipher=Cipher.getInstance(PATTERN);cipher.init(Cipher.DECRYPT_MODE,secretKey);byte[] decrypt_data= cipher.doFinal(Base64.getDecoder().decode(txt));return new String(decrypt_data, ENCODE);}

非对称加密:RSA加密

public static KeyPairGenerator generator;public static KeyPair keyPair;public static final class keystore{public byte[] public_key;public byte[] private_key;}static {try {generator=KeyPairGenerator.getInstance("RSA");generator.initialize(2048);keyPair=generator.generateKeyPair();}catch (Exception err){err.printStackTrace();}}public static keystore get_key_pair(){keystore key_value=new keystore();key_value.public_key=keyPair.getPublic().getEncoded();key_value.private_key=keyPair.getPrivate().getEncoded();return key_value;}public static byte[] encrypt_data_by_public(byte[] msg, byte[] key) throws Exception {KeyFactory keyFactory=KeyFactory.getInstance("RSA");X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(key);PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.ENCRYPT_MODE,publicKey);return cipher.doFinal(msg);}public static byte[] decrypt_data_by_private(byte[] msg, byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(key);PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.DECRYPT_MODE,privateKey);return cipher.doFinal(msg);}public static byte[] encrypt_data_by_private(byte[] msg, byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(key);PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.ENCRYPT_MODE,privateKey);return cipher.doFinal(msg);}public static byte[] decrypt_data_by_public(byte[] msg,byte[] key) throws Exception{KeyFactory keyFactory=KeyFactory.getInstance("RSA");X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(key);PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());cipher.init(Cipher.DECRYPT_MODE,publicKey);return cipher.doFinal(msg);}

随机数生成（字符串）:

public static String GenerateKey(){StringBuffer buffer=new StringBuffer();Random random=new Random();for (int i = 0; i < 16; i++) {buffer.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));}return buffer.toString();}

随机数生成（整形）:

public static int GenerateIntKey(){Random random=new Random();return random.nextInt(999999999);}

Base64编码转字符串:

public static String Base64ToString(byte[]data){return Base64.getEncoder().encodeToString(data);}

字节数组转字符串:

public static String BytesToString(byte[]data,String encode) throws UnsupportedEncodingException {return new String(data,encode);}

代码测试:

import VirtualUtils.CryptoUtils;
public class Main {public static void main(String[]args) throws Exception {String msg="This is a test";CryptoUtils.keystore keystore=CryptoUtils.get_key_pair();byte[] en=CryptoUtils.encrypt_data_by_public(msg.getBytes("utf-8"),keystore.public_key);System.out.println(CryptoUtils.Base64ToString(CryptoUtils.decrypt_data_by_private(en,keystore.private_key)));System.out.println(new String(CryptoUtils.decrypt_data_by_private(en,keystore.private_key)));byte[] en1=CryptoUtils.encrypt_data_by_private(msg.getBytes("utf-8"),keystore.private_key);System.out.println(CryptoUtils.Base64ToString(en1));System.out.println(CryptoUtils.BytesToString(CryptoUtils.decrypt_data_by_public(en1,keystore.public_key),"utf-8"));}
}

测试结果: