在開發(fā)項(xiàng)目中，我們經(jīng)常會(huì)需要打印日志，這樣方便開發(fā)人員了解接口調(diào)用情況及定位錯(cuò)誤問題，很多時(shí)候?qū)τ贑ontroller或者是Service的入?yún)⒑统鰠⑿枰蛴∪罩?#xff0c;但是我們又不想重復(fù)的在每個(gè)方法里去使用logger打印，這個(gè)時(shí)候希望有一個(gè)管理者統(tǒng)一來打印，這時(shí)Spring AOP就派上用場了，利用切面的思想，我們在進(jìn)入、出入Controller或Service時(shí)給它切一刀實(shí)現(xiàn)統(tǒng)一日志打印。

SpringAOP不僅可以實(shí)現(xiàn)在不產(chǎn)生新類的情況下打印日志，還可以管理事務(wù)、緩存等。具體可以了解官方文檔。https://docs.spring.io/spring/docs/current/spring-framework-reference/core.html#aop-api

基礎(chǔ)概念

在使用SpringAOP，這里還是先簡單講解一些基本的知識(shí)吧，如果說的不對(duì)請及時(shí)指正，這里主要是根據(jù)官方文檔來總結(jié)的。本章內(nèi)容主要涉及的知識(shí)點(diǎn)。

Pointcut: 切入點(diǎn)，這里用于定義規(guī)則，進(jìn)行方法的切入（形象的比喻就是一把刀）。

JoinPoint: 連接點(diǎn)，用于連接定義的切面。

Before: 在之前，在切入點(diǎn)方法執(zhí)行之前。

AfterReturning: 在切入點(diǎn)方法結(jié)束并返回時(shí)執(zhí)行。

這里除了SpringAOP相關(guān)的知識(shí)，還涉及到了線程相關(guān)的知識(shí)點(diǎn)，因?yàn)槲覀冃枰紤]多線程中它們各自需要保存自己的變量，所以就用到了ThreadLocal。

依賴引入

這里主要是用到aop和mongodb，在pom.xml文件中加入以下依賴即可:

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId> </dependency> <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-mongodb</artifactId> </dependency>

相關(guān)實(shí)體類

/*** 請求日志實(shí)體，用于保存請求日志*/ @Document class WebLog {var id: String = ""var request: String? = nullvar response: String? = nullvar time: Long? = nullvar requestUrl: String? = nullvar requestIp: String? = nullvar startTime: Long? = nullvar endTime: Long? = nullvar method: String? = nulloverride fun toString(): String {return ObjectMapper().writeValueAsString(this)} }/*** 業(yè)務(wù)對(duì)象，上一章講JPA中有定義*/ @Document class Student {@Idvar id :String? = nullvar name :String? = nullvar age :Int? = 0var gender :String? = nullvar sclass :String ?= nulloverride fun toString(): String {return ObjectMapper().writeValueAsString(this)} }

定義切面

定義切入點(diǎn)

/*** 定義一個(gè)切入，只要是為io.intodream..web下public修飾的方法都要切入*/ @Pointcut(value = "execution(public * io.intodream..web.*.*(..))") fun webLog() {}

定義切入點(diǎn)的表達(dá)式還可以使用within、如:

/*** 表示在io.intodream.web包下的方法都會(huì)被切入*/ @Pointcut(value = "within(io.intodream.web..*")

定義一個(gè)連接點(diǎn)

/*** 切面的連接點(diǎn)，并聲明在該連接點(diǎn)進(jìn)入之前需要做的一些事情*/ @Before(value = "webLog()") @Throws(Throwable::class) fun doBefore(joinPoint: JoinPoint) {val webLog = WebLog()webLog.startTime = System.currentTimeMillis()val attributes = RequestContextHolder.getRequestAttributes() as ServletRequestAttributes?val request = attributes!!.requestval args = joinPoint.argsval paramNames = (joinPoint.signature as CodeSignature).parameterNamesval params = HashMap<String, Any>(args.size)for (i in args.indices) {if (args[i] !is BindingResult) {params[paramNames[i]] = args[i]}}webLog.id = UUID.randomUUID().toString()webLog.request = params.toString()webLog.requestUrl = request.requestURI.toString()webLog.requestIp = request.remoteAddrwebLog.method = request.methodwebRequestLog.set(webLog)logger.info("REQUEST={} {}; SOURCE IP={}; ARGS={}", request.method,request.requestURL.toString(), request.remoteAddr, params) }

方法結(jié)束后執(zhí)行

@AfterReturning(returning = "ret", pointcut = "webLog()") @Throws(Throwable::class) fun doAfterReturning(ret: Any) {val webLog = webRequestLog.get()webLog.response = ret.toString()webLog.endTime = System.currentTimeMillis()webLog.time = webLog.endTime!! - webLog.startTime!!logger.info("RESPONSE={}; SPEND TIME={}MS", ObjectMapper().writeValueAsString(ret), webLog.time)logger.info("webLog:{}", webLog)webLogRepository.save(webLog)webRequestLog.remove() }

這里的主要思路是，在方法執(zhí)行前，先記錄詳情的請求參數(shù)，請求方法，請求ip， 請求方式及進(jìn)入時(shí)間，然后將對(duì)象放入到ThreadLocal中，在方法結(jié)束后并取到對(duì)應(yīng)的返回對(duì)象且計(jì)算出請求耗時(shí)，然后將請求日志保存到mongodb中。

完成的代碼

package io.intodream.kotlin07.aspectimport com.fasterxml.jackson.databind.ObjectMapper import io.intodream.kotlin07.dao.WebLogRepository import io.intodream.kotlin07.entity.WebLog import org.aspectj.lang.JoinPoint import org.aspectj.lang.annotation.AfterReturning import org.aspectj.lang.annotation.Aspect import org.aspectj.lang.annotation.Before import org.aspectj.lang.annotation.Pointcut import org.aspectj.lang.reflect.CodeSignature import org.slf4j.Logger import org.slf4j.LoggerFactory import org.springframework.beans.factory.annotation.Autowired import org.springframework.core.annotation.Order import org.springframework.stereotype.Component import org.springframework.validation.BindingResult import org.springframework.web.context.request.RequestContextHolder import org.springframework.web.context.request.ServletRequestAttributes import java.util.*/*** {描述}** @author yangxianxi@gogpay.cn* @date 2019/4/10 19:06**/ @Aspect @Order(5) @Component class WebLogAspect {private val logger:Logger = LoggerFactory.getLogger(WebLogAspect::class.java)private val webRequestLog: ThreadLocal<WebLog> = ThreadLocal()@Autowired lateinit var webLogRepository: WebLogRepository/*** 定義一個(gè)切入，只要是為io.intodream..web下public修飾的方法都要切入*/@Pointcut(value = "execution(public * io.intodream..web.*.*(..))")fun webLog() {}/*** 切面的連接點(diǎn)，并聲明在該連接點(diǎn)進(jìn)入之前需要做的一些事情*/@Before(value = "webLog()")@Throws(Throwable::class)fun doBefore(joinPoint: JoinPoint) {val webLog = WebLog()webLog.startTime = System.currentTimeMillis()val attributes = RequestContextHolder.getRequestAttributes() as ServletRequestAttributes?val request = attributes!!.requestval args = joinPoint.argsval paramNames = (joinPoint.signature as CodeSignature).parameterNamesval params = HashMap<String, Any>(args.size)for (i in args.indices) {if (args[i] !is BindingResult) {params[paramNames[i]] = args[i]}}webLog.id = UUID.randomUUID().toString()webLog.request = params.toString()webLog.requestUrl = request.requestURI.toString()webLog.requestIp = request.remoteAddrwebLog.method = request.methodwebRequestLog.set(webLog)logger.info("REQUEST={} {}; SOURCE IP={}; ARGS={}", request.method,request.requestURL.toString(), request.remoteAddr, params)}@AfterReturning(returning = "ret", pointcut = "webLog()")@Throws(Throwable::class)fun doAfterReturning(ret: Any) {val webLog = webRequestLog.get()webLog.response = ret.toString()webLog.endTime = System.currentTimeMillis()webLog.time = webLog.endTime!! - webLog.startTime!!logger.info("RESPONSE={}; SPEND TIME={}MS", ObjectMapper().writeValueAsString(ret), webLog.time)logger.info("webLog:{}", webLog)webLogRepository.save(webLog)webRequestLog.remove()} }

這里定義的是Web層的切面，對(duì)于Service層我也可以定義一個(gè)切面，但是對(duì)于Service層的進(jìn)入和返回的日志我們可以把級(jí)別稍等調(diào)低一點(diǎn)，這里改debug,具體實(shí)現(xiàn)如下：

package io.intodream.kotlin07.aspectimport com.fasterxml.jackson.databind.ObjectMapper import org.aspectj.lang.JoinPoint import org.aspectj.lang.annotation.AfterReturning import org.aspectj.lang.annotation.Aspect import org.aspectj.lang.annotation.Before import org.aspectj.lang.annotation.Pointcut import org.aspectj.lang.reflect.CodeSignature import org.slf4j.Logger import org.slf4j.LoggerFactory import org.springframework.core.annotation.Order import org.springframework.stereotype.Component import org.springframework.validation.BindingResult/*** service層所有public修飾的方法調(diào)用返回日志** @author yangxianxi@gogpay.cn* @date 2019/4/10 17:33**/ @Aspect @Order(2) @Component class ServiceLogAspect {private val logger: Logger = LoggerFactory.getLogger(ServiceLogAspect::class.java)/****/@Pointcut(value = "execution(public * io.intodream..service.*.*(..))")private fun serviceLog(){}@Before(value = "serviceLog()")fun deBefore(joinPoint: JoinPoint) {val args = joinPoint.argsval codeSignature = joinPoint.signature as CodeSignatureval paramNames = codeSignature.parameterNamesval params = HashMap<String, Any>(args.size).toMutableMap()for (i in args.indices) {if (args[i] !is BindingResult) {params[paramNames[i]] = args[i]}}logger.debug("CALL={}; ARGS={}", joinPoint.signature.name, params)}@AfterReturning(returning = "ret", pointcut = "serviceLog()")@Throws(Throwable::class)fun doAfterReturning(ret: Any) {logger.debug("RESPONSE={}", ObjectMapper().writeValueAsString(ret))} }

接口測試

這里就不在貼出Service層和web的代碼實(shí)現(xiàn)了，因?yàn)槲沂强截愔皩PA那一章的代碼，唯一不同的就是加入了切面，切面的加入并不影響原來的業(yè)務(wù)流程。

執(zhí)行如下請求:

我們會(huì)在控制臺(tái)看到如下日志

2019-04-14 19:32:27.208 INFO 4914 --- [nio-9000-exec-1] i.i.kotlin07.aspect.WebLogAspect : REQUEST=POST http://localhost:9000/api/student/; SOURCE IP=0:0:0:0:0:0:0:1; ARGS={student={"id":"5","name":"Rose","age":17,"gender":"Girl","sclass":"Second class"}} 2019-04-14 19:32:27.415 INFO 4914 --- [nio-9000-exec-1] org.mongodb.driver.connection : Opened connection [connectionId{localValue:2, serverValue:4}] to localhost:27017 2019-04-14 19:32:27.431 INFO 4914 --- [nio-9000-exec-1] i.i.kotlin07.aspect.WebLogAspect : RESPONSE={"id":"5","name":"Rose","age":17,"gender":"Girl","sclass":"Second class"}; SPEND TIME=239MS 2019-04-14 19:32:27.431 INFO 4914 --- [nio-9000-exec-1] i.i.kotlin07.aspect.WebLogAspect : webLog:{"id":"e7b0ca1b-0a71-4fa0-9f5f-95a29d4d54a1","request":"{student={"id":"5","name":"Rose","age":17,"gender":"Girl","sclass":"Second class"}}","response":"{"id":"5","name":"Rose","age":17,"gender":"Girl","sclass":"Second class"}","time":239,"requestUrl":"/api/student/","requestIp":"0:0:0:0:0:0:0:1","startTime":1555241547191,"endTime":1555241547430,"method":"POST"}

查看數(shù)據(jù)庫會(huì)看到我們的請求日志已經(jīng)寫入了:

這里有一個(gè)地方需要注意，在Service層的實(shí)現(xiàn)，具體如下:

return studentRepository.findById(id).get()

這里的findById會(huì)返回一個(gè)Optional<T>對(duì)象，如果沒有查到數(shù)據(jù)，我們使用get獲取數(shù)據(jù)會(huì)出現(xiàn)異常java.util.NoSuchElementException: No value present，可以改為返回對(duì)象可以為空只要在返回類型后面加一個(gè)?即可，同時(shí)調(diào)用Optional的ifPresent進(jìn)行安全操作。

總結(jié)

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