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

public interface UserDetails extends Serializable {

 //返回分配给用户的角色列表
 Collection<? extends GrantedAuthority> getAuthorities();
 
 //返回密码
 String getPassword();

 //返回帐号
 String getUsername();

 // 账户是否未过期
 boolean isAccountNonExpired();

 // 账户是否未锁定
 boolean isAccountNonLocked();

 // 密码是否未过期
 boolean isCredentialsNonExpired();

 // 账户是否激活
 boolean isEnabled();
}

public interface UserDetailsService {
 UserDetails loadUserByUsername(String var1) throws UsernameNotFoundException;
}

/**
 * Created by Yuicon on 2017/5/14.
 */
public class User implements UserDetails {

 private final String id;
 //帐号,这里是我数据库里的字段
 private final String account;
 //密码
 private final String password;
 //角色集合
 private final Collection<? extends GrantedAuthority> authorities;

 User(String id, String account, String password, Collection<? extends GrantedAuthority> authorities) {
  this.id = id;
  this.account = account;
  this.password = password;
  this.authorities = authorities;
 }

 //返回分配给用户的角色列表
 @Override
 public Collection<? extends GrantedAuthority> getAuthorities() {
  return authorities;
 }

 @JsonIgnore
 public String getId() {
  return id;
 }

 @JsonIgnore
 @Override
 public String getPassword() {
  return password;
 }
 
 //虽然我数据库里的字段是 `account` ,这里还是要写成 `getUsername()`,因为是继承的接口
 @Override
 public String getUsername() {
  return account;
 }
 // 账户是否未过期
 @JsonIgnore
 @Override
 public boolean isAccountNonExpired() {
  return true;
 }
 // 账户是否未锁定
 @JsonIgnore
 @Override
 public boolean isAccountNonLocked() {
  return true;
 }
 // 密码是否未过期
 @JsonIgnore
 @Override
 public boolean isCredentialsNonExpired() {
  return true;
 }
 // 账户是否激活
 @JsonIgnore
 @Override
 public boolean isEnabled() {
  return true;
 }
}

/**
 * Created by Yuicon on 2017/5/14.
 */
@Service
public class UserDetailsServiceImpl implements UserDetailsService {
 
 // jpa
 @Autowired
 private UserRepository userRepository;

 /**
  * 提供一种从用户名可以查到用户并返回的方法
  * @param account 帐号
  * @return UserDetails
  * @throws UsernameNotFoundException
  */
 @Override
 public UserDetails loadUserByUsername(String account) throws UsernameNotFoundException {
  // 这里是数据库里的用户类
  User user = userRepository.findByAccount(account);

  if (user == null) {
   throw new UsernameNotFoundException(String.format("没有该用户 '%s'.", account));
  } else {
   //这里返回上面继承了 UserDetails 接口的用户类,为了简单我们写个工厂类
   return UserFactory.create(user);
  }
 }
}

/**
 * Created by Yuicon on 2017/5/14.
 */
final class UserFactory {

 private UserFactory() {
 }

 static User create(User user) {
  return new User(
    user.getId(),
    user.getAccount(),
    user.getPassword(),
   mapToGrantedAuthorities(user.getRoles().stream().map(Role::getName).collect(Collectors.toList()))
  );
 }
 
 //将与用户类一对多的角色类的名称集合转换为 GrantedAuthority 集合
 private static List<GrantedAuthority> mapToGrantedAuthorities(List<String> authorities) {
  return authorities.stream()
    .map(SimpleGrantedAuthority::new)
    .collect(Collectors.toList());
 }
}

/**
 * Created by Yuicon on 2017/5/14.
 */
@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

 // Spring会自动寻找实现接口的类注入,会找到我们的 UserDetailsServiceImpl 类
 @Autowired
 private UserDetailsService userDetailsService;

 @Autowired
 public void configureAuthentication(AuthenticationManagerBuilder authenticationManagerBuilder) throws Exception {
  authenticationManagerBuilder
    // 设置UserDetailsService
    .userDetailsService(this.userDetailsService)
    // 使用BCrypt进行密码的hash
    .passwordEncoder(passwordEncoder());
 }

 // 装载BCrypt密码编码器
 @Bean
 public PasswordEncoder passwordEncoder() {
  return new BCryptPasswordEncoder();
 }

 //允许跨域
 @Bean
 public WebMvcConfigurer corsConfigurer() {
  return new WebMvcConfigurerAdapter() {
   @Override
   public void addCorsMappings(CorsRegistry registry) {
    registry.addMapping("/**").allowedOrigins("*")
      .allowedMethods("GET", "HEAD", "POST","PUT", "DELETE", "OPTIONS")
      .allowCredentials(false).maxAge(3600);
   }
  };
 }

 @Override
 protected void configure(HttpSecurity httpSecurity) throws Exception {
  httpSecurity
    // 取消csrf
    .csrf().disable()
    // 基于token，所以不需要session
    .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
    .authorizeRequests()
    .antMatchers(HttpMethod.OPTIONS, "/**").permitAll()
    // 允许对于网站静态资源的无授权访问
    .antMatchers(
      HttpMethod.GET,
      "/",
      "/*.html",
      "/favicon.ico",
      "/**/*.html",
      "/**/*.css",
      "/**/*.js",
      "/webjars/**",
      "/swagger-resources/**",
      "/*/api-docs"
    ).permitAll()
    // 对于获取token的rest api要允许匿名访问
    .antMatchers("/auth/**").permitAll()
    // 除上面外的所有请求全部需要鉴权认证
    .anyRequest().authenticated();
  // 禁用缓存
  httpSecurity.headers().cacheControl();
 }
}

/**
 * 在 @PreAuthorize 中我们可以利用内建的 SPEL 表达式：比如 'hasRole()' 来决定哪些用户有权访问。
 * 需注意的一点是 hasRole 表达式认为每个角色名字前都有一个前缀 'ROLE_'。所以这里的 'ADMIN' 其实在
 * 数据库中存储的是 'ROLE_ADMIN' 。这个 @PreAuthorize 可以修饰Controller也可修饰Controller中的方法。
 **/
@RestController
@RequestMapping("/users")
@PreAuthorize("hasRole('USER')") //有ROLE_USER权限的用户可以访问
public class UserController {

 @Autowired
 private UserRepository repository;

 @PreAuthorize("hasRole('ADMIN')")//有ROLE_ADMIN权限的用户可以访问
 @RequestMapping(method = RequestMethod.GET)
 public List<User> getUsers() {
  return repository.findAll();
 }
}