springboot AOP中，通过解析SpEL 表达式动态获取参数值

切面注解

import com.bn.document.constants.FmDeptCatalogueConstants;import java.lang.annotation.*;@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface FmDeptCatalogueAopAnnotation {/*** 权限类型*/FmDeptCatalogueConstants value();/*** 目录id*/String catalogueId() ;
}

切面类 (整个类) 重点代码在下面

package com.bn.document.aop;import com.bn.document.constants.FmDeptCatalogueConstants;
import com.bn.document.po.FmDeptCataloguePo;
import com.bn.document.po.LoginUser;
import com.bn.document.service.FmDeptCatalogueService;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.stereotype.Component;import java.lang.reflect.Method;
import java.util.List;@Aspect
@Component
public class MyAspect {private final ExpressionParser parser = new SpelExpressionParser();private final ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();@Autowiredprivate FmDeptCatalogueService fmDeptCatalogueService;/*** 定义切入点：拦截带有 @MyCustomAnnotation 的方法*/@Pointcut("@annotation(com.bn.document.aop.FmDeptCatalogueAopAnnotation)")public void cataloguePointcut() {}/*** 环绕增强：获取注解中的权限类型，检查用户权限*/@Around("cataloguePointcut()")public Object aroundAdvice(ProceedingJoinPoint joinPoint) throws Throwable {// 获取方法上的注解FmDeptCatalogueAopAnnotation annotation = ((MethodSignature) joinPoint.getSignature()).getMethod().getAnnotation(FmDeptCatalogueAopAnnotation.class);if (annotation == null) {return joinPoint.proceed(); // 没有注解直接放行}// 获取权限类型FmDeptCatalogueConstants permissionType = annotation.value();// 获取方法参数值Object[] args = joinPoint.getArgs();LoginUser loginUser = null;// 遍历参数列表，提取 LoginUser 和 catalogueIdfor (Object arg : args) {if (arg instanceof LoginUser) {loginUser = (LoginUser) arg;}}// 开始解析  SpEL 表达式MethodSignature signature = (MethodSignature) joinPoint.getSignature();Method method = signature.getMethod();// 获取方法参数名 + 参数值，用于构建 SpEL 上下文String[] paramNames = parameterNameDiscoverer.getParameterNames(method);// 构建 EvaluationContext，并绑定参数EvaluationContext context = new StandardEvaluationContext();if (paramNames != null && args.length > 0) {for (int i = 0; i < paramNames.length; i++) {context.setVariable(paramNames[i], args[i]); // 绑定参数}}// 解析表达式中的目录IDString catalogueIdExpr = annotation.catalogueId();Long catalogueId = parser.parseExpression(catalogueIdExpr).getValue(context, Long.class);// 判断参数是否为空if (loginUser == null || loginUser.getDeptId() == null) {throw new SecurityException("登录信息错误");}if (catalogueId == null || catalogueId <= 0) {throw new SecurityException("目录ID不能为空");}// 调用服务层查询权限List<FmDeptCataloguePo> result = fmDeptCatalogueService.getFmDeptCataloguePoWithDeptId(loginUser.getDeptId(),catalogueId,permissionType);// 如果权限不存在if (result == null || result.isEmpty()) {throw new SecurityException("您没有【" + permissionType.getDes() + "】权限");}// 否则放行return joinPoint.proceed();}}

重点【开始解析 SpEL 表达式】

// 开始解析  SpEL 表达式MethodSignature signature = (MethodSignature) joinPoint.getSignature();Method method = signature.getMethod();// 获取方法参数名 + 参数值，用于构建 SpEL 上下文String[] paramNames = parameterNameDiscoverer.getParameterNames(method);// 构建 EvaluationContext，并绑定参数EvaluationContext context = new StandardEvaluationContext();if (paramNames != null && args.length > 0) {for (int i = 0; i < paramNames.length; i++) {context.setVariable(paramNames[i], args[i]); // 绑定参数}}// 解析表达式中的目录IDString catalogueIdExpr = annotation.catalogueId();Long catalogueId = parser.parseExpression(catalogueIdExpr).getValue(context, Long.class);

使用

1.获取对象中的属性值

 @Override@Transactional(rollbackFor = Exception.class)@FmDeptCatalogueAopAnnotation(value = FmDeptCatalogueConstants.MODIFY_PERMISSION, catalogueId = "#sysFileCataloguePo.parentId")public CommonResponse insertSub(SysFileCataloguePo sysFileCataloguePo,LoginUser loginUser) {
}

1.1 结果

2.直接取值

 @Override@FmDeptCatalogueAopAnnotation(value = FmDeptCatalogueConstants.DETAILS_PERMISSION, catalogueId = "#id")public CommonResponse getSub(Long id,  LoginUser loginUser) {}

2.1 结果

完结！！！