为什么在嵌入式 Tomcat 中使用 <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%> 会出现以下错误？如果我尝试使用相同 POM 的相同 JSP 而没有嵌入依赖项并将其部署到 Tomcat 服务器，则根本不会出现错误。
我在这里阅读了一些带有类似问题的问题，一些答案建议添加某些依赖项。我试过了，但老实说，我相信这个问题与嵌入式 Tomcat 直接相关。
发现的最接近的问题让我想知道在应用程序启动期间我缺少一些配置，但我没有弄清楚在我的情况下我可以在应用程序启动期间设置什么。
入门级：
public class App
{
private static File getRootFolder() {
try {
File root;
String runningJarPath = App.class.getProtectionDomain().getCodeSource().getLocation().toURI().getPath().replaceAll("\\\\", "/");
int lastIndexOf = runningJarPath.lastIndexOf("/target/");
if (lastIndexOf < 0) {
root = new File("");
} else {
root = new File(runningJarPath.substring(0, lastIndexOf));
}
System.out.println("application resolved root folder: " + root.getAbsolutePath());
return root;
} catch (URISyntaxException ex) {
throw new RuntimeException(ex);
}
}
public static void main(String[] args) throws Exception {
File root = getRootFolder();
System.setProperty("org.apache.catalina.startup.EXIT_ON_INIT_FAILURE", "true");
Tomcat tomcat = new Tomcat();
Path tempPath = Files.createTempDirectory("tomcat-base-dir");
tomcat.setBaseDir(tempPath.toString());
//The port that we should run on can be set into an environment variable
//Look for that variable and default to 8080 if it isn't there.
String webPort = System.getenv("PORT");
if (webPort == null || webPort.isEmpty()) {
webPort = "8080";
}
tomcat.setPort(Integer.valueOf(webPort));
File webContentFolder = new File(root.getAbsolutePath(), "src/main/webapp/");
if (!webContentFolder.exists()) {
webContentFolder = Files.createTempDirectory("default-doc-base").toFile();
}
StandardContext ctx = (StandardContext) tomcat.addWebapp("", webContentFolder.getAbsolutePath());
//Set execution independent of current thread context classloader (compatibility with exec:java mojo)
ctx.setParentClassLoader(App.class.getClassLoader());
//Disable TLD scanning by default
if (System.getProperty(Constants.SKIP_JARS_PROPERTY) == null && System.getProperty(Constants.SKIP_JARS_PROPERTY) == null) {
System.out.println("disabling TLD scanning");
StandardJarScanFilter jarScanFilter = (StandardJarScanFilter) ctx.getJarScanner().getJarScanFilter();
jarScanFilter.setTldSkip("*");
}
System.out.println("configuring app with basedir: " + webContentFolder.getAbsolutePath());
// Declare an alternative location for your "WEB-INF/classes" dir
// Servlet 3.0 annotation will work
File additionWebInfClassesFolder = new File(root.getAbsolutePath(), "target/classes");
WebResourceRoot resources = new StandardRoot(ctx);
WebResourceSet resourceSet;
if (additionWebInfClassesFolder.exists()) {
resourceSet = new DirResourceSet(resources, "/WEB-INF/classes", additionWebInfClassesFolder.getAbsolutePath(), "/");
System.out.println("loading WEB-INF resources from as '" + additionWebInfClassesFolder.getAbsolutePath() + "'");
} else {
resourceSet = new EmptyResourceSet(resources);
}
resources.addPreResources(resourceSet);
ctx.setResources(resources);
tomcat.start();
tomcat.getServer().await();
}
}
错误：
org.apache.jasper.JasperException: The absolute uri: http://www.springframework.org/tags/form cannot be resolved in either web.xml or the jar files deployed with this application
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:55)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:277)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:75)
org.apache.jasper.compiler.TagLibraryInfoImpl.generateTldResourcePath(TagLibraryInfoImpl.java:243)
org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:124)
org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:421)
org.apache.jasper.compiler.Parser.parseDirective(Parser.java:479)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1435)
org.apache.jasper.compiler.Parser.parse(Parser.java:139)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1243)
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:859)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
org.apache.jasper.JasperException: The absolute uri: http://www.springframework.org/tags/form cannot be resolved in either web.xml or the jar files deployed with this application
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:55)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:277)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:75)
org.apache.jasper.compiler.TagLibraryInfoImpl.generateTldResourcePath(TagLibraryInfoImpl.java:243)
org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:124)
org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:421)
org.apache.jasper.compiler.Parser.parseDirective(Parser.java:479)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1435)
org.apache.jasper.compiler.Parser.parse(Parser.java:139)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1243)
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:859)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
索引.jsp：
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<body>
<h2>Uploading a file.. </h2>
<form:form method="POST" commandName="file" enctype="multipart/form-data">
Upload your file please:
<input type="file" name="file" />
<input type="submit" value="upload2" />
<form:errors path="file" cssStyle="color: #ff0000;" />
</form:form>
</body>
</html>
聚甲醛：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.myCompany</groupId>
<artifactId>AuthFileUpload</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>AuthFileUpload</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<tomcat.version>8.0.32</tomcat.version>
<java.version>1.8</java.version>
<maven.compiler.plugin.version>2.1</maven.compiler.plugin.version>
<spring.version>4.2.5.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-core</artifactId>
<version>${tomcat.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-logging-juli</artifactId>
<version>${tomcat.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<version>${tomcat.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jasper</artifactId>
<version>${tomcat.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jasper-el</artifactId>
<version>${tomcat.version}</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jsp-api</artifactId>
<version>${tomcat.version}</version>
</dependency>
<!-- the next dependencies I added because I read in somewhere someone has fixed similar error by adding them-->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-taglibs</artifactId>
<version>4.0.4.RELEASE</version>
</dependency>
</dependencies>
<build>
<finalName>embeddedTomcatSample</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven.compiler.plugin.version}</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>appassembler-maven-plugin</artifactId>
<version>1.1.1</version>
<configuration>
<assembleDirectory>target</assembleDirectory>
<programs>
<program>
<mainClass>launch.Main</mainClass>
<name>webapp</name>
</program>
</programs>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>assemble</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
*** 编辑于 2016/March/03
从 Eclipse 成功运行
应用程序解析的根文件夹：C:\STS\wsRestTemplate\AuthFileUpload
使用 basedir 配置应用程序：C:\STS\wsRestTemplate\AuthFileUpload\src\main\webapp
从 'C:\STS\wsRestTemplate\AuthFileUpload\target\classes' 加载 WEB-INF 资源
从 java -jar myExecutableJar.jar 运行，我得到 HTTP Status 404 - /upload in browser
应用程序解析的根文件夹：C:\Program Files\Java\jdk1.8.0_45\jre
使用 basedir 配置应用程序：C:\Users\e049447\AppData\Local\Temp\default-doc-base2930321463161270235
*** 我们可以看到没有“loading WEB-INF...”INFO。显然，因为additionWebInfClassesFolder.exists() 返回false，所以“resourceSet = new EmptyResourceSet(resources)”。在这种类似于 Eclipse 的场景中，我必须加载 WEB-INF 什么？