Java | 使用切面AOP拦截并修改Controller接口请求参数

不念不忘少年蓝@ 2024-03-17 12:14 22阅读 0赞

#### 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.*;
    
    /**
     * @Description controller
     * @Author Liao Jy
     * @Date 2023/6/28
     */
    @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;
    
    /**
     * @Description DefaultArgumentsAspect
     * @Author LiaoJy
     * @Date 2023/6/28
     */
    
    @Component
    @Aspect
    @Slf4j
    public 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  
    ![在这里插入图片描述][4e5b5484cf1b4ce39a55285123f97ef3.png]
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！

1.  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  
    ![在这里插入图片描述][f78699a695044e4d867feb594e337a04.png]
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<java.lang.String>"}},"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!

1.  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  
    ![在这里插入图片描述][fdb0bf70c2c84254bda396f2856e51d8.png]
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

1.  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。

[4e5b5484cf1b4ce39a55285123f97ef3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/b13563de20bd402ea4ba71c0bf33eaaa.png
[f78699a695044e4d867feb594e337a04.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/9ce030da89e34afb81af96c448706b73.png
[fdb0bf70c2c84254bda396f2856e51d8.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/197ac268627b408e9f858109a0706889.png