【报错】java.io.FileNotFoundException: E:\repository\xalan\xalan\2.7.1\serializer.jar (系统找不到指定的文件。)

错误描述：

springboot使用内置tomcat集成jsp进行web开发的时候，运行起来，总有两三个找不到在指定文件的警告，看起来很难受。

java.io.FileNotFoundException: E:\repository\xalan\xalan\2.7.1\xercesImpl.jar (系统找不到指定的文件。)
	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]

错误原因：

网上查了一下，主要的原因是内置的springboot内置tomcat的版本是9以上。tomcat在8.5.2 中 修改了加载jar的方式，8.5.2 版本会解析jar中MANIFEST.MF文件，当该文件包含class-path属性时，会把该属性对象值，解析成需要加载的jar给加载进来。

参考博客：https://blog.csdn.net/lveliu/article/details/77772828

解决办法：

在主启动类的main方法后面加上一个Bean，让tomcat不去扫描那些jar即可。

    @Bean
    public TomcatServletWebServerFactory tomcatFactory(){
        return new TomcatServletWebServerFactory(){

            @Override
            protected void postProcessContext(Context context) {
                ((StandardJarScanner) context.getJarScanner()).setScanManifest(false);
            }
        };
    }

将上面代码加入到主启动类的main方法后面，即可解决问题。