在Java中DES加密/解密的实现[工具类]

Bertha 。 2023-02-14 10:40 31阅读 0赞

使用前需导入**Crypto**包：

<dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-crypto</artifactId>
        <version>5.2.1.RELEASE</version>
    </dependency>

Utils工具类：

import sun.misc.BASE64Decoder;
    import sun.misc.BASE64Encoder;
    
    import javax.crypto.Cipher;
    import javax.crypto.KeyGenerator;
    import javax.crypto.NoSuchPaddingException;
    import java.security.InvalidKeyException;
    import java.security.Key;
    import java.security.NoSuchAlgorithmException;
    import java.security.SecureRandom;
    
    /**
     * @author Piconjo
     * @date 2020/6/1  20:15
     */
    
    public class DesUtil {
        
    
        private static DesUtil instance;
        private Key key;
        private Cipher encryptCipher;
        private Cipher decryptCipher;
    
        // 密钥
        private static final String SECRET_KEY="iloveumybaby";
    
        protected DesUtil() {
        
        }
    
        protected DesUtil(String strKey) {
        
            key = setKey(strKey);
            try {
        
                encryptCipher = Cipher.getInstance("DES");
                encryptCipher.init(Cipher.ENCRYPT_MODE, key);
                decryptCipher = Cipher.getInstance("DES");
                decryptCipher.init(Cipher.DECRYPT_MODE, key);
            } catch (NoSuchAlgorithmException e) {
        
                e.printStackTrace();
            } catch (NoSuchPaddingException e) {
        
                e.printStackTrace();
            } catch (InvalidKeyException e) {
        
                e.printStackTrace();
            }
        }
    
        // 初始化实例
        public static DesUtil getInstance() {
        
            if (instance == null) {
        
                instance = new DesUtil(SECRET_KEY);
            }
            return instance;
        }
    
        //  根据参数生成KEY
        private Key setKey(String strKey) {
        
            try {
        
                KeyGenerator _generator = KeyGenerator.getInstance("DES");
                _generator.init(new SecureRandom(strKey.getBytes()));
                return _generator.generateKey();
    
            } catch (Exception e) {
        
                e.printStackTrace();
            }
    
            return null;
        }
    
        // 加密 - String明文输入 String密文输出
        public String setEncString(String strMing) {
        
            BASE64Encoder base64en = new BASE64Encoder();
            try {
        
                byte[] byteMing = strMing.getBytes("UTF-8");
                byte[] byteMi = getEncCode(byteMing);
                return base64en.encode(byteMi);
            } catch (Exception e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        // 加密 - byte[]明文输入 byte[]密文输出
        private byte[] getEncCode(byte[] byteS) {
        
            byte[] byteFina = null;
            try {
        
                byteFina = encryptCipher.doFinal(byteS);
            } catch (Exception e) {
        
                e.printStackTrace();
            }
            return byteFina;
        }
    
        // 解密 - String密文输入 String明文输出
        public String setDesString(String strMi) {
        
            BASE64Decoder base64De = new BASE64Decoder();
            try {
        
                byte[] byteMi = base64De.decodeBuffer(strMi);
                byte[] byteMing = getDesCode(byteMi);
                return new String(byteMing, "UTF-8");
            } catch (Exception e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        // 解密 - byte[]密文输入 byte[]明文输出
        private byte[] getDesCode(byte[] byteD) {
        
            byte[] byteFina = null;
            try {
        
                byteFina = decryptCipher.doFinal(byteD);
            } catch (Exception e) {
        
                e.printStackTrace();
            }
            return byteFina;
        }
    
    	// 单测
        public static void main(String[] args) {
        
            DesUtil desUtil = DesUtil.getInstance();
    
            String code= dtDesUtil.setEncString("111111@qq.com");
            System.out.println(code);
            System.out.println(dtDesUtil.setDesString(code));
        }
    }

## 使用须知： ##

使用前 调用DesUtil的`getInstance()`方法 生成DesUtil类的实例  
然后再使用返回的DesUtil对象进行密码加密解密操作

**不能直接调用DesUtil里的方法进行加密解密 否则会报空指针异常**

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