SpringBoot集成logback.xml日志配置文件找不到错误

问题描述

配置内容：

#logginglogging.config=classpath:/logback-lightsword.xml

报错日志：

java.lang.IllegalStateException: java.io.FileNotFoundException: class path resource [/logback-lightsword.xml] cannot be resolved to URL because it does not exist    at org.springframework.boot.logging.LoggingApplicationListener.initializeSystem(LoggingApplicationListener.java:311)    at org.springframework.boot.logging.LoggingApplicationListener.initialize(LoggingApplicationListener.java:272)    at org.springframework.boot.logging.LoggingApplicationListener.onApplicationEnvironmentPreparedEvent(LoggingApplicationListener.java:235)    at org.springframework.boot.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:208)    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:167)    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:122)    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:72)    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:338)    at org.springframework.boot.SpringApplication.run(SpringApplication.java:309)    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1187)    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1176)    at com.springboot.in.action.LightSwordApplication$.delayedEndpoint$com$springboot$in$action$LightSwordApplication$1(LightSwordApplication.scala:6)    at com.springboot.in.action.LightSwordApplication$delayedInit$body.apply(LightSwordApplication.scala:5)    at scala.Function0.apply$mcV$sp(Function0.scala:34)    at scala.Function0.apply$mcV$sp$(Function0.scala:34)    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)    at scala.App.$anonfun$main$1$adapted(App.scala:76)    at scala.App$$Lambda$5/1451043227.apply(Unknown Source)    at scala.collection.immutable.List.foreach(List.scala:389)    at scala.App.main(App.scala:76)    at scala.App.main$(App.scala:74)    at com.springboot.in.action.LightSwordApplication$.main(LightSwordApplication.scala:5)    at com.springboot.in.action.LightSwordApplication.main(LightSwordApplication.scala)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:497)    at org_scala_tools_maven_executions.MainHelper.runMain(MainHelper.java:161)    at org_scala_tools_maven_executions.MainWithArgsInFile.main(MainWithArgsInFile.java:26)Caused by: java.io.FileNotFoundException: class path resource [/logback-lightsword.xml] cannot be resolved to URL because it does not exist    at org.springframework.util.ResourceUtils.getURL(ResourceUtils.java:135)    at org.springframework.boot.logging.LoggingApplicationListener.initializeSystem(LoggingApplicationListener.java:303)    ... 30 common frames omitted

原因分析

涉及报错的源码在org.springframework.util.ResourceUtils

    /**     * Resolve the given resource location to a {@code java.net.URL}.     * <p>Does not check whether the URL actually exists; simply returns     * the URL that the given location would correspond to.     * @param resourceLocation the resource location to resolve: either a     * "classpath:" pseudo URL, a "file:" URL, or a plain file path     * @return a corresponding URL object     * @throws FileNotFoundException if the resource cannot be resolved to a URL     */    public static URL getURL(String resourceLocation) throws FileNotFoundException {        Assert.notNull(resourceLocation, "Resource location must not be null");        if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {            String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());            ClassLoader cl = ClassUtils.getDefaultClassLoader();            URL url = (cl != null ? cl.getResource(path) : ClassLoader.getSystemResource(path));            if (url == null) {                String description = "class path resource [" + path + "]";                throw new FileNotFoundException(description +                        " cannot be resolved to URL because it does not exist");            }            return url;        }        try {            // try URL            return new URL(resourceLocation);        }        catch (MalformedURLException ex) {            // no URL -> treat as file path            try {                return new File(resourceLocation).toURI().toURL();            }            catch (MalformedURLException ex2) {                throw new FileNotFoundException("Resource location [" + resourceLocation +                        "] is neither a URL not a well-formed file path");            }        }    }

通过源码，我们可以看出spring配置文件里这个locations是uri表示，也就是说我们写的logback-dev.xml是当前相对路径。

解决方案

spring配置文件里这个locations是相对路径，要访问classpath，要使用相对路径：

logging.config=classpath:logback-dev.xml