一、Authentication Provider概述
Authentication Provider是Spring Security中最核心的概念之一。简单来说,它是处理用户认证的组件,负责验证用户身份是否合法,并在验证通过后返回身份信息给Spring Security。Authentication Provider对于Spring Security来说相当于是身份验证的入口口。通过向Authentication Provider提供认证请求,我们可以得到认证结果,进而提供其他权限控制服务。
在Spring Security中,Authentication Provider是一个接口,其实现类需要覆盖authenticate(Authentication authentication)方法。当用户请求认证时,Authentication Provider就会尝试对用户提供的信息进行认证评估,并返回Authentication对象。
二、Authentication Provider的使用方式
除了以前常用的XML方式进行配置,Spring Security 5开始提供了一种更为方便的Java Config方式进行Authentication Provider的配置。如果我们要使用这种方式,需要创建一个继承了WebSecurityConfigurerAdapter的配置类,并在该类中重写configure(AuthenticationManagerBuilder auth)方法,然后在该方法中注册Authentication Provider。下面是一个简单的示例代码:
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
auth.authenticationProvider(new CustomAuthenticationProvider());
}
private static class CustomUserDetailsService implements UserDetailsService {
@Override
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
return User.builder()
.username(username)
.password("{noop}password")
.roles("USER")
.build();
}
}
private static class CustomAuthenticationProvider implements AuthenticationProvider {
private final UserDetailsService userDetailsService;
public CustomAuthenticationProvider() {
this.userDetailsService = new CustomUserDetailsService();
}
@Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
String username = authentication.getName();
String password = authentication.getCredentials().toString();
UserDetails user = userDetailsService.loadUserByUsername(username);
if (password.equals(user.getPassword())) {
return new UsernamePasswordAuthenticationToken(username, password, user.getAuthorities());
} else {
throw new BadCredentialsException("Password is incorrect");
}
}
@Override
public boolean supports(Class authentication) {
return authentication.equals(UsernamePasswordAuthenticationToken.class);
}
}
}
三、Authentication Provider的自定义
如果默认实现的Authentication Provider不能满足我们的需求,我们也可以自己实现一个定制化的Authentication Provider。下面是一个自定义的Authentication Provider的示例代码:
import org.springframework.security.authentication.AuthenticationProvider;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.stereotype.Component;
@Component
public class CustomAuthenticationProvider implements AuthenticationProvider {
@Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
String username = authentication.getName();
String password = authentication.getCredentials().toString();
// 在此处根据用户名和密码进行自定义认证
if ("admin".equals(username) && "password".equals(password)) {
return new UsernamePasswordAuthenticationToken(username, password, new ArrayList<>());
} else {
throw new BadCredentialsException("Authentication failed");
}
}
@Override
public boolean supports(Class authentication) {
return UsernamePasswordAuthenticationToken.class.isAssignableFrom(authentication);
}
}
四、Authentication Provider的扩展
在Spring Security中,我们还可以通过继承AbstractUserDetailsAuthenticationProvider类来扩展Authentication Provider的功能。AbstractUserDetailsAuthenticationProvider提供了一些模板方法,可以让我们方便地自定义扩展自己的Authentication Provider。下面是一个自定义扩展了AbstractUserDetailsAuthenticationProvider的示例代码:
import org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;
@Component
public class CustomAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider {
@Override
protected UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException {
//在此处实现根据用户名和密码查找用户信息的逻辑
}
@Override
protected void additionalAuthenticationChecks(UserDetails userDetails, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException {
//在此处实现额外的认证检查逻辑
}
}