我想保护管理面板。我已添加到Spring Security：
.antMatchers("/admin/**").hasAuthority("ADMIN")
我的用户模型包含（实现用户详细信息）：
@Override
@OneToMany(fetch=FetchType.LAZY, mappedBy = "user", cascade = CascadeType.ALL)
@JsonIgnore
public Set<Authority> getAuthorities() {
return authorities;
}
public void setAuthorities(Set<Authority> authorities){
this.authorities = authorities;
}
权威模型包含（实现GrantedAuthure）：
@ManyToOne
@JoinColumn(name="user_id")
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
问题：当我添加，这一行andMatcher并尝试访问此控制器时，它显示错误：
<pre>java.lang.NullPointerException
org.springframework.security.core.authority.AuthorityUtils.authorityListToSet(AuthorityUtils.java:39)
org.springframework.security.access.expression.SecurityExpressionRoot.getAuthoritySet(SecurityExpressionRoot.java:128)
org.springframework.security.access.expression.SecurityExpressionRoot.hasRole(SecurityExpressionRoot.java:60)
org.springframework.security.access.expression.SecurityExpressionRoot.hasAuthority(SecurityExpressionRoot.java:52)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:483)
由于安全评估可能是在事务之外进行的，因此使用EAGER获取权限。我还建议延迟初始化，以便该方法永远不会返回null。
@OneToMany(fetch=FetchType.EAGER, mappedBy = "user", cascade = CascadeType.ALL)
public Set<Authority> getAuthorities() {
if (authorities == null)
authorities = new HashSet<Authority>();
return authorities;
}
