引入Spring Security后，在Controller的方法中会出现Spring Security的方法注解与AOP同时存在的问题，这是就会设计顺序问题

@Controller
public class HelloController{
	@RequestMapping(value = "/hello")
	@BeforeController
	@PreAuthorize("validate(#user)")
	public void hello(@RequestParam("user) String user) {
		// 业务代码 
	}
}

上述Controller中@BeforeController是一个业务AOP，@PreAuthorize是来授权校验user。按照业务逻辑，执行顺序应该是如下：

但实际是@BeforeController在@PreAuthorize之前。
其实@PreAuthorize也是依赖于AOP实现，当多个AOP在一个方法上时就会有顺序问题。在Aop中指定顺序的方法有：

@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface BeforeController {

}

• 1、@Order注解

  @Aspect
  @Component
  @Order(0)
  public class BeforeControllerAction {
      @Before("@annotation(org.numb.web.aop.BeforeController)")
      public void before(final JoinPoint joinPoint) {
          // before切面业务代码
      }
  }
  

  @Order注解里面的值是一个整数，数值越大优先级越低，默认是Integer.MIN_VALUE，即最低优先级。
• 2、实现org.springframework.core.Ordered接口

  @Aspect
  @Component
  public class BeforeControllerAction implements Ordered {
      @Before("@annotation(org.numb.web.aop.BeforeController)")
      public void before(final JoinPoint joinPoint) {
          // before切面业务代码
      }
  
  
      @Override
      public int getOrder() {
          return 0;
      }
  }
  

• 3、通过配置文件配置顺序

  <aop:config expose-proxy="true">
      <aop:pointcut id="beforeController" expression="@annotation(org.numb.web.aop.BeforeController)"/>
      <aop:aspect ref="beforeControllerAction" id="beforeControllerAction">
          <aop:before method="before" pointcut-ref="beforeController"/>
      </aop:aspect>
  </aop:config>
  

而Spring Security的执行顺序本质上也是由AOP决定，可以通过指定order的方式确定：

@EnableGlobalMethodSecurity(order = 0)

查看源码可见

public @interface EnableGlobalMethodSecurity {
...
	/**
	 * Indicate the ordering of the execution of the security advisor when multiple
	 * advices are applied at a specific joinpoint. The default is
	 * {@link Ordered#LOWEST_PRECEDENCE}.
	 * @return the order the security advisor should be applied
	 */
	int order() default Ordered.LOWEST_PRECEDENCE;

}