从外部文件获取JPA凭据

# application.properties

# 数据库连接配置
spring.datasource.url=jdbc:mysql://localhost:3306/mydatabase
spring.datasource.username=dbuser
spring.datasource.password=dbpassword

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

@Component
public class JpaCredentials {
    @Value("${spring.datasource.url}")
    private String url;

    @Value("${spring.datasource.username}")
    private String username;

    @Value("${spring.datasource.password}")
    private String password;

    // 省略getter和setter方法
}

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

@Service
public class JpaService {
    private final JpaCredentials jpaCredentials;

    @Autowired
    public JpaService(JpaCredentials jpaCredentials) {
        this.jpaCredentials = jpaCredentials;
    }

    public void doSomethingWithJpa() {
        String url = jpaCredentials.getUrl();
        String username = jpaCredentials.getUsername();
        String password = jpaCredentials.getPassword();

        // 使用JPA进行数据库操作
        // ...
    }
}