在Spring Security中使用BCrypt进行密码编码的解决方法如下：

1. 首先，确保你的项目中已经添加了Spring Security和BCrypt的依赖。可以在pom.xml文件中添加以下依赖：

    org.springframework.boot
    spring-boot-starter-security



    org.springframework.security
    spring-security-crypto

2. 创建一个实现了UserDetailsService接口的类，该类用于加载用户信息。可以在该类中使用BCrypt对密码进行编码。以下是一个示例：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.User;
import import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Service;

@Service
public class UserDetailsServiceImpl implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        UserEntity userEntity = userRepository.findByUsername(username);
        if (userEntity == null) {
            throw new UsernameNotFoundException("User not found");
        }
        return User.builder()
                .username(userEntity.getUsername())
                .password(new BCryptPasswordEncoder().encode(userEntity.getPassword()))
                .roles(userEntity.getRoles())
                .build();
    }
}

3. 在Spring Security的配置类中，将UserDetailsService注册为AuthenticationProvider。以下是一个示例：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationProvider;
import org.springframework.security.authentication.dao.DaoAuthenticationProvider;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserDetailsService userDetailsService;

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.authenticationProvider(authenticationProvider());
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .antMatchers("/admin").hasRole("ADMIN")
                .antMatchers("/user").hasAnyRole("ADMIN", "USER")
                .antMatchers("/").permitAll()
                .and().formLogin();
    }

    @Bean
    public AuthenticationProvider authenticationProvider() {
        DaoAuthenticationProvider provider = new DaoAuthenticationProvider();
        provider.setUserDetailsService(userDetailsService);
        provider.setPasswordEncoder(new BCryptPasswordEncoder());
        return provider;
    }
}

在上述代码中，我们将UserDetailsService注册为AuthenticationProvider，并设置BCryptPasswordEncoder作为密码编码器。这样当用户登录时，Spring Security将使用BCryptPasswordEncoder对输入的密码进行编码，并与数据库中的密码进行比较。

通过以上步骤，你就可以在Spring Security中使用BCrypt进行密码编码了。