给我一个java springboot的消息推送加密例子。代码示例

在Java Spring Boot中实现消息推送的加密，可以使用对称加密算法，比如AES。以下是一个简单的加密和解密消息的例子：

首先，需要添加一个依赖到你的`pom.xml`文件中，以使用Spring Boot：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

接着，创建一个工具类`EncryptionUtil`来实现消息的加密和解密功能：

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;
import java.util.Base64;

public class EncryptionUtil {

    private static final String ALGORITHM = "AES";

    public static SecretKey generateKey() throws Exception {
        KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);
        keyGen.init(256, new SecureRandom());
        return keyGen.generateKey();
    }

    public static String encrypt(String data, SecretKey secretKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData);
    }

    public static String decrypt(String encryptedData, SecretKey secretKey) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] decodedData = Base64.getDecoder().decode(encryptedData);
        byte[] decryptedData = cipher.doFinal(decodedData);
        return new String(decryptedData);
    }
}

在`application.properties`中添加加密密钥：

encryption.key=your-encryption-key-here

然后，在你的服务类中使用这个工具类来加密和解密消息：

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
public class MessageService {

    private final SecretKey secretKey;

    public MessageService(@Value("${encryption.key}") String key) throws Exception {
        this.secretKey = EncryptionUtil.generateKey();
    }

    public String encryptMessage(String message) throws Exception {
        return EncryptionUtil.encrypt(message, secretKey);
    }

    public String decryptMessage(String encryptedMessage) throws Exception {
        return EncryptionUtil.decrypt(encryptedMessage, secretKey);
    }
}

在控制器中，你可以这样使用`MessageService`：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/message")
public class MessageController {

    private final MessageService messageService;

    @Autowired
    public MessageController(MessageService messageService) {
        this.messageService = messageService;
    }

    @PostMapping("/encrypt")
    public String encryptMessage(@RequestBody String message) {
        try {
            return messageService.encryptMessage(message);
        } catch (Exception e) {
            e.printStackTrace();
            return "Error during encryption";
        }
    }

    @PostMapping("/decrypt")
    public String decryptMessage(@RequestBody String encryptedMessage) {
        try {
            return messageService.decryptMessage(encryptedMessage);
        } catch (Exception e) {
            e.printStackTrace();
            return "Error during decryption";
        }
    }
}