import org.springframework.boot.autoconfigure.security.oauth2.resource.PrincipalExtractor; //导入依赖的package包/类
public void setPrincipalExtractor(PrincipalExtractor principalExtractor) {
    Assert.notNull(principalExtractor, "PrincipalExtractor must not be null");
    this.principalExtractor = principalExtractor;
}
 

import org.springframework.boot.autoconfigure.security.oauth2.resource.PrincipalExtractor; //导入依赖的package包/类
@Bean
public PrincipalExtractor principalExtractor(OAuth2RestOperations template) {
	return map -> {
		return map.get("preferred_username");
	};
}
 

import org.springframework.boot.autoconfigure.security.oauth2.resource.PrincipalExtractor; //导入依赖的package包/类
@Bean
public PrincipalExtractor principalExtractor(final OAuth2RestOperations template) {
	return map -> {
		return map.get("preferred_username");
	};
}
 

import org.springframework.boot.autoconfigure.security.oauth2.resource.PrincipalExtractor; //导入依赖的package包/类
public CustomUserInfoTokenServices(String userInfoEndpointUrl, String clientId, PrincipalExtractor principalExtractor) {
    super(userInfoEndpointUrl, clientId);
    setPrincipalExtractor(principalExtractor);
}
 

import org.springframework.boot.autoconfigure.security.oauth2.resource.PrincipalExtractor; //导入依赖的package包/类
@Bean
public PrincipalExtractor userDetailPrincipalExtractor(){
	return new UserDetailPrincipalExtractor();
}