关注common wx： CodingTechWork

引言

  在开发过程中，会有一些需求将controller层的一些方法入参进行全量转换，最容易想到的可能是在调用下层service方法时，调用公共的方法进行入参转换，这时带来的唯一问题就是代码不雅观，比较冗余。那还有什么方法可以更优雅的解决这个问题吗？答案是有的：切面。
  我们实现一个AOP切面程序，对入参中的需转换的参数进行专项转换，而无需在各个controller层的各个方法中进行转换处理。

实践

controller类

package com.test.selfcoding.controller;import com.test.selfcoding.bean.PersonBean;import com.test.selfcoding.service.HelloWorldService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*;@RestController@RequestMapping("/hello/world")public class HelloWorldController {    @Autowired    private HelloWorldService helloWorldService;    @GetMapping("/test1")    public String testGetHelloWorld() {        return helloWorldService.getHelloWolrd();    }    @PostMapping("/test2")    public String testPostHelloWord(@RequestBody PersonBean personBean) {        return helloWorldService.postHelloWorld(personBean);    }    @GetMapping("/test3")    public String testPostHelloWord(@RequestParam String personName) {        return personName + ", hi world!";    }}

切面类

package com.test.selfcoding.aspect;import com.alibaba.fastjson.JSON;import lombok.extern.slf4j.Slf4j;import org.aspectj.lang.JoinPoint;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;import org.springframework.stereotype.Component;import org.springframework.web.context.request.RequestContextHolder;import org.springframework.web.context.request.ServletRequestAttributes;import javax.servlet.http.HttpServletRequest;import java.lang.reflect.Field;import java.lang.reflect.Modifier;import java.util.Arrays;@Component@Aspect@Slf4jpublic class DefaultArgumentsAspect {    @Before(value = "execution(* com.test.selfcoding.controller..*(..))")    public void doBefore(JoinPoint joinPoint) {        try {        //获取入参列表            Object[] args = joinPoint.getArgs();            log.info("args: {}", JSON.toJSONString(args));            //入参判空            if (null == args || args.length == 0) {                log.info("no fields!");                return;            }            //获取第一个入参（主要针对@RequestBody，一般只会有一个入参，若遇到多个@RequestParam，需循环处理）            Object arg = args[0];            //获取字段域            Field[] fields = arg.getClass().getDeclaredFields();            log.info("getDeclaredFields: {}", JSON.toJSONString(fields));//判断入参中是否有"name"            if (Arrays.stream(fields).noneMatch(item -> "name".equals(item.getName()))) {                log.info("no name field!");                return;            }            //入参中有"name"，获取该字段            Field field = arg.getClass().getDeclaredField("name");            //判断是否可使用            boolean accessible = ((!Modifier.isPublic(field.getModifiers())                    || !Modifier.isPublic(field.getDeclaringClass().getModifiers())                    || Modifier.isFinal(field.getModifiers())) && !field.isAccessible());            //若不可用，则需要进行setAccessible            if (accessible) {                ServletRequestAttributes attributes                        = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();                // 获取request对象                HttpServletRequest request = attributes.getRequest();                log.info("method name: {}", request.getRequestURI());                field.setAccessible(true);                //将name参数替换为system                field.set(arg, "system");            }        } catch (Exception e) {            log.error("切面参数设置异常", e);        }    }}

验证

无参测试接口1

1. 接口调用
   
2. 控制台日志

2023-06-28 18:06:06.060  INFO 6495 --- [nio-8001-exec-1] c.t.s.aspect.DefaultArgumentsAspect      : args: []2023-06-28 18:06:06.061  INFO 6495 --- [nio-8001-exec-1] c.t.s.aspect.DefaultArgumentsAspect      : no fields!2023-06-28 18:06:06.066  INFO 6495 --- [nio-8001-exec-1] c.t.s.s.impl.HelloWorldServiceImpl       : getHelloWolrd() get str success.result: hugh, hello world！

3. 结果分析
   未获取到参数，正常走接口。打印no fields!，无需转换参数。

不包含指定参数测试接口2

1. 接口调用
   

2. 控制台日志

2023-06-28 18:08:04.040  INFO 6495 --- [nio-8001-exec-5] c.t.s.aspect.DefaultArgumentsAspect      : args: ["xiaowang"]2023-06-28 18:08:04.055  INFO 6495 --- [nio-8001-exec-5] c.t.s.aspect.DefaultArgumentsAspect      : getDeclaredFields: [{"accessible":false,"annotatedType":{"annotatedGenericComponentType":{"annotations":[],"declaredAnnotations":[],"type":"char"},"annotations":[],"declaredAnnotations":[],"type":"[C"},"annotations":[],"declaringClass":"java.lang.String","enumConstant":false,"genericType":"[C","modifiers":18,"name":"value","synthetic":false,"type":"[C"},{"accessible":false,"annotatedType":{"annotations":[],"declaredAnnotations":[],"type":"int"},"annotations":[],"declaringClass":"java.lang.String","enumConstant":false,"genericType":"int","modifiers":2,"name":"hash","synthetic":false,"type":"int"},{"accessible":false,"annotatedType":{"annotations":[],"declaredAnnotations":[],"type":"long"},"annotations":[],"declaringClass":"java.lang.String","enumConstant":false,"genericType":"long","modifiers":26,"name":"serialVersionUID","synthetic":false,"type":"long"},{"accessible":false,"annotatedType":{"annotatedGenericComponentType":{"annotations":[],"declaredAnnotations":[],"type":"java.io.ObjectStreamField"},"annotations":[],"declaredAnnotations":[],"type":"[Ljava.io.ObjectStreamField;"},"annotations":[],"declaringClass":"java.lang.String","enumConstant":false,"genericType":"[Ljava.io.ObjectStreamField;","modifiers":26,"name":"serialPersistentFields","synthetic":false,"type":"[Ljava.io.ObjectStreamField;"},{"accessible":false,"annotatedType":{"annotatedActualTypeArguments":[{"annotations":[],"declaredAnnotations":[],"type":"java.lang.String"}],"annotations":[],"declaredAnnotations":[],"type":{"actualTypeArguments":["java.lang.String"],"rawType":"java.util.Comparator","typeName":"java.util.Comparator"}},"annotations":[],"declaringClass":"java.lang.String","enumConstant":false,"genericType":{"$ref":"$[4].annotatedType.type"},"modifiers":25,"name":"CASE_INSENSITIVE_ORDER","synthetic":false,"type":"java.util.Comparator"}]2023-06-28 18:08:04.056  INFO 6495 --- [nio-8001-exec-5] c.t.s.aspect.DefaultArgumentsAspect      : no name field!

3. 结果分析
   未获取到指定的参数，正常走接口。打印no name field!，无需转换参数。

包含指定参数测试接口3

1. 接口调用
   

2. 控制台日志

2023-06-28 18:10:15.481  INFO 6495 --- [nio-8001-exec-9] c.t.s.aspect.DefaultArgumentsAspect      : args: [{"age":1,"name":"xiaohong"}]2023-06-28 18:10:15.482  INFO 6495 --- [nio-8001-exec-9] c.t.s.aspect.DefaultArgumentsAspect      : getDeclaredFields: [{"accessible":false,"annotatedType":{"annotations":[],"declaredAnnotations":[],"type":"java.lang.String"},"annotations":[],"declaringClass":"com.test.selfcoding.bean.PersonBean","enumConstant":false,"genericType":"java.lang.String","modifiers":2,"name":"name","synthetic":false,"type":"java.lang.String"},{"accessible":false,"annotatedType":{"annotations":[],"declaredAnnotations":[],"type":"int"},"annotations":[],"declaringClass":"com.test.selfcoding.bean.PersonBean","enumConstant":false,"genericType":"int","modifiers":2,"name":"age","synthetic":false,"type":"int"}]2023-06-28 18:10:15.482  INFO 6495 --- [nio-8001-exec-9] c.t.s.aspect.DefaultArgumentsAspect      : method name: /hello/world/test2

3. 结果分析
   获取到指定的参数，进行name值替换为system，切面转换参数成功。

来源地址：https://blog.csdn.net/Andya_net/article/details/131442326