Spring Security: 401重定向至单页app

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/api/**").authenticated()
                .anyRequest().permitAll()
                .and()
            .formLogin()
                .loginPage("/login")
                .permitAll()
                .and()
            .logout()
                .logoutUrl("/logout")
                .permitAll()
                .and()
            .exceptionHandling()
                .authenticationEntryPoint(new HttpStatusEntryPoint(HttpStatus.UNAUTHORIZED))
                .and()
            .csrf().disable();
    }
}