錯誤描述：
springboot使用內置tomcat集成jsp進行web開發的時候，運行起來，總有兩三個找不到在指定文件的警告，看起來很難受。
java.io.FileNotFoundException: E:\repository\xalan\xalan\2.7.1\xercesImpl.jar (系統找不到指定的文件。)
at java.util.zip.ZipFile.open(Native Method) ~[na:1.8.0_65]
at java.util.zip.ZipFile.<init>(ZipFile.java:219) ~[na:1.8.0_65]
at java.util.zip.ZipFile.<init>(ZipFile.java:149) ~[na:1.8.0_65]
at java.util.jar.JarFile.<init>(JarFile.java:166) ~[na:1.8.0_65]
at java.util.jar.JarFile.<init>(JarFile.java:130) ~[na:1.8.0_65]
at org.apache.tomcat.util.compat.JreCompat.jarFileNewInstance(JreCompat.java:176) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.JarFileUrlJar.<init>(JarFileUrlJar.java:65) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.JarFactory.newInstance(JarFactory.java:49) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.StandardJarScanner.process(StandardJarScanner.java:374) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.StandardJarScanner.processURLs(StandardJarScanner.java:309) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.StandardJarScanner.doScanClassPath(StandardJarScanner.java:266) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.scan.StandardJarScanner.scan(StandardJarScanner.java:229) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.jasper.servlet.TldScanner.scanJars(TldScanner.java:262) [tomcat-embed-jasper-9.0.21.jar:9.0.21]
at org.apache.jasper.servlet.TldScanner.scan(TldScanner.java:104) [tomcat-embed-jasper-9.0.21.jar:9.0.21]
at org.apache.jasper.servlet.JasperInitializer.onStartup(JasperInitializer.java:83) [tomcat-embed-jasper-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5132) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) [tomcat-embed-core-9.0.21.jar:9.0.21]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_65]
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) [tomcat-embed-core-9.0.21.jar:9.0.21]
at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134) [na:1.8.0_65]
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374) [tomcat-embed-core-9.0.21.jar:9.0.21]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_65]
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75) [tomcat-embed-core-9.0.21.jar:9.0.21]
at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134) [na:1.8.0_65]
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:421) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:932) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.startup.Tomcat.start(Tomcat.java:456) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:105) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:86) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:414) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:178) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) [spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:742) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:389) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1213) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1202) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE]
at cn.edu.xidian.research.group.web.IcefoxResearchGroupWebApplication.main(IcefoxResearchGroupWebApplication.java:13) [classes/:na]
錯誤原因：
網上查了一下，主要的原因是內置的springboot內置tomcat的版本是9以上。tomcat在8.5.2 中 修改了加載jar的方式，8.5.2 版本會解析jar中MANIFEST.MF文件，當該文件包含class-path屬性時，會把該屬性對象值，解析成需要加載的jar給加載進來。
參考博客：https://blog.csdn.net/lveliu/article/details/77772828
解決辦法：
在主啓動類的main方法後面加上一個Bean，讓tomcat不去掃描那些jar即可。
@Bean
public TomcatServletWebServerFactory tomcatFactory(){
return new TomcatServletWebServerFactory(){
@Override
protected void postProcessContext(Context context) {
((StandardJarScanner) context.getJarScanner()).setScanManifest(false);
}
};
}
將上面代碼加入到主啓動類的main方法後面，即可解決問題。