spring-boot jsp whitelabel error page问题解决

spring-boot jsp whitelabel error page问题解决

spring-boot配置jsp，访问：http://127.0.0.1:8080，显示如下错误信息：

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Dec 12 13:04:58 CST 2017
There was an unexpected error (type=Not Found, status=404).
/WEB-INF/jsp/test1.jsp

打印Tomcat上下文指向目录：

public static void main(Stringp[] args){
    ConfigurableApplicationContext context = SpringApplication.run(ApplicationMain.class, args);
    ServletContext context1 = context.getBean(ServletContext.class);
    URL url = context1.getResource("/");
    System.out.prinltn("ContextRoot Path: {}", url.getFile());
}

Output:
/C:/Users/ADMINI~1/AppData/Local/Temp/tomcat-docbase.2813863602259672077.8081/

说明Tomcat未能正确指向项目路径，打断点翻看源代码TomcatEmbeddedServletContainerFactory.java：

protected void prepareContext(Host host, ServletContextInitializer[] initializers) {
        // 准备容器上下文，获取可用文档根目录，
        // 一般为：src/main/webapp/;public;static
        // 如果未找到则创建临时目录，即上面打印的结果。
        File docBase = getValidDocumentRoot();

        docBase = (docBase != null ? docBase : createTempDir("tomcat-docbase"));
        final TomcatEmbeddedContext context = new TomcatEmbeddedContext();
        context.setName(getContextPath());
        context.setDisplayName(getDisplayName());
        context.setPath(getContextPath());
        context.setDocBase(docBase.getAbsolutePath());
        context.addLifecycleListener(new FixContextListener());
        context.setParentClassLoader(
                this.resourceLoader != null ? this.resourceLoader.getClassLoader()
                        : ClassUtils.getDefaultClassLoader());
        resetDefaultLocaleMapping(context);
        addLocaleMappings(context);
        try {
            context.setUseRelativeRedirects(false);
        }
        catch (NoSuchMethodError ex) {
            // Tomcat is < 8.0.30. Continue
        }
        SkipPatternJarScanner.apply(context, this.tldSkipPatterns);
        WebappLoader loader = new WebappLoader(context.getParentClassLoader());
        loader.setLoaderClass(TomcatEmbeddedWebappClassLoader.class.getName());
        loader.setDelegate(true);
        context.setLoader(loader);
        if (isRegisterDefaultServlet()) {
            addDefaultServlet(context);
        }
        if (shouldRegisterJspServlet()) {
            addJspServlet(context);
            addJasperInitializer(context);
            context.addLifecycleListener(new StoreMergedWebXmlListener());
        }
        context.addLifecycleListener(new LifecycleListener() {

            @Override
            public void lifecycleEvent(LifecycleEvent event) {
                if (event.getType().equals(Lifecycle.CONFIGURE_START_EVENT)) {
                    TomcatResources.get(context)
                            .addResourceJars(getUrlsOfJarsWithMetaInfResources());
                }
            }

        });
        ServletContextInitializer[] initializersToUse = mergeInitializers(initializers);
        configureContext(context, initializersToUse);
        host.addChild(context);
        postProcessContext(context);
    }

一层一层分析spring-boot内嵌Tomcat容器源码后，可写个配置TomcatConfig.java解决此问题：

@Configuration
public class TomcatConfig {

    @Bean
    public EmbeddedServletContainerFactory embeddedServletContainerFactory() {
        ConfigurableEmbeddedServletContainer factory = new TomcatEmbeddedServletContainerFactory();
        // 请自行优化目录，可写配置参数
        factory.setDocumentRoot(new File("D:\\Workspace\\IDEA\\spring-boot-web-demo\\src\\main\\webapp\\"));
        return (EmbeddedServletContainerFactory) factory;
    }
}

Good Luck! :)

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