A Servlet Example Showing The Jakarta Spec Implementation in Apache Tomcat.
Recently I have built a Servlet example here:
The example is quite self-explanatory here is the FileUploadServlet in the project:
@WebServlet(name = "FileUploadServlet", urlPatterns = {"/upload"})
@MultipartConfig(
fileSizeThreshold = 1024 * 1024 * 1, // 1 MB
maxFileSize = 1024 * 1024 * 10, // 10 MB
maxRequestSize = 1024 * 1024 * 100 // 100 MB
)
public class FileUploadServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
/* Receive file uploaded to the Servlet from the HTML5 form */
Part filePart = request.getPart("file");
String fileName = filePart.getSubmittedFileName();
String filePath = "/tmp/" + fileName;
for (Part part : request.getParts()) {
part.write(filePath);
}
response.getWriter().print("The file uploaded sucessfully: " + filePath);
}
}
The project can be built into WAR file with mvn install, and it can be deployed into containers like Apache Tomcat or WildFly. In the example some jakarta servlet annotations are used like jakarta.servlet.annotation.WebServlet or jakarta.servlet.annotation.MultipartConfig.
These annotations are coming from the jakarta specs itself:
These annotations are implemented by the containers. For example, the Apache Tomcat will be responsible to support the @MultipartConfig annotation. Here is the source code repo of the Tomcat:
Here is the relative part related with the @MultiplartConfig annotation in the Tomcat code base:
➤ grep -rn 'MultipartConfig' * 23:11:34
java/org/apache/catalina/Wrapper.java:20:import jakarta.servlet.MultipartConfigElement;
java/org/apache/catalina/Wrapper.java:320: MultipartConfigElement getMultipartConfigElement();
java/org/apache/catalina/Wrapper.java:329: void setMultipartConfigElement(
java/org/apache/catalina/Wrapper.java:330: MultipartConfigElement multipartConfig);
java/org/apache/catalina/core/StandardContext.java:170: * Allow multipart/form-data requests to be parsed even when the target servlet doesn't specify @MultipartConfig or
java/org/apache/catalina/core/StandardContext.java:1222: * Set to <code>true</code> to allow requests mapped to servlets that do not explicitly declare @MultipartConfig or
java/org/apache/catalina/core/StandardWrapper.java:39:import jakarta.servlet.MultipartConfigElement;
java/org/apache/catalina/core/StandardWrapper.java:45:import jakarta.servlet.annotation.MultipartConfig;
java/org/apache/catalina/core/StandardWrapper.java:208: protected MultipartConfigElement multipartConfigElement = null;
java/org/apache/catalina/core/StandardWrapper.java:879: MultipartConfig annotation = servlet.getClass().getAnnotation(MultipartConfig.class);
java/org/apache/catalina/core/StandardWrapper.java:881: multipartConfigElement = new MultipartConfigElement(annotation);
java/org/apache/catalina/core/StandardWrapper.java:1197: public MultipartConfigElement getMultipartConfigElement() {
java/org/apache/catalina/core/StandardWrapper.java:1202: public void setMultipartConfigElement(MultipartConfigElement multipartConfigElement) {
java/org/apache/catalina/core/ApplicationServletRegistration.java:26:import jakarta.servlet.MultipartConfigElement;
java/org/apache/catalina/core/ApplicationServletRegistration.java:135: public void setMultipartConfig(MultipartConfigElement multipartConfig) {
java/org/apache/catalina/core/ApplicationServletRegistration.java:136: wrapper.setMultipartConfigElement(multipartConfig);
java/org/apache/catalina/Context.java:113: * do not explicitly declare @MultipartConfig or have
java/org/apache/catalina/connector/LocalStrings_ja.properties:61:coyoteRequest.noMultipartConfig=multi-part 構成が提供されていないため、partを処理できません
java/org/apache/catalina/connector/LocalStrings_zh_CN.properties:59:coyoteRequest.noMultipartConfig=由于没有提供multi-part配置，无法处理parts
java/org/apache/catalina/connector/LocalStrings_fr.properties:61:coyoteRequest.noMultipartConfig=Impossible de traiter des parties, parce qu'aucune configuration multi-parties n'a été fournie
java/org/apache/catalina/connector/LocalStrings_ko.properties:56:coyoteRequest.noMultipartConfig=어떤 multi-part 설정도 제공되지 않았기 때문에, part들을 처리할 수 없습니다.
java/org/apache/catalina/connector/LocalStrings.properties:61:coyoteRequest.noMultipartConfig=Unable to process parts as no multi-part configuration has been provided
java/org/apache/catalina/connector/LocalStrings_cs.properties:27:coyoteRequest.noMultipartConfig=Nelze zpracovat části, protože nebyla poskytnuta žádná multi-part konfigurace
java/org/apache/catalina/connector/LocalStrings_pt_BR.properties:16:coyoteRequest.noMultipartConfig=Impossível processar partes já que não há configuração de multi-part
java/org/apache/catalina/connector/LocalStrings_es.properties:42:coyoteRequest.noMultipartConfig=Imposible procesar partes debido a que se ha proveído una configuración no multipartes
java/org/apache/catalina/connector/Request.java:49:import jakarta.servlet.MultipartConfigElement;
java/org/apache/catalina/connector/Request.java:2419: MultipartConfigElement mce = getWrapper().getMultipartConfigElement();
java/org/apache/catalina/connector/Request.java:2423: mce = new MultipartConfigElement(null, connector.getMaxPostSize(), connector.getMaxPostSize(),
java/org/apache/catalina/connector/Request.java:2426: partsParseException = new IllegalStateException(sm.getString("coyoteRequest.noMultipartConfig"));
java/org/apache/catalina/startup/ContextConfig.java:46:import jakarta.servlet.MultipartConfigElement;
java/org/apache/catalina/startup/ContextConfig.java:1490: wrapper.setMultipartConfigElement(new MultipartConfigElement(multipartdef.getLocation(), maxFileSize,
java/jakarta/servlet/ServletRegistration.java:90: void setMultipartConfig(MultipartConfigElement multipartConfig);
java/jakarta/servlet/MultipartConfigElement.java:19:import jakarta.servlet.annotation.MultipartConfig;
java/jakarta/servlet/MultipartConfigElement.java:22: * The programmatic equivalent of {@link jakarta.servlet.annotation.MultipartConfig} used to configure multi-part
java/jakarta/servlet/MultipartConfigElement.java:27:public class MultipartConfigElement {
java/jakarta/servlet/MultipartConfigElement.java:40: public MultipartConfigElement(String location) {
java/jakarta/servlet/MultipartConfigElement.java:61: public MultipartConfigElement(String location, long maxFileSize, long maxRequestSize, int fileSizeThreshold) {
java/jakarta/servlet/MultipartConfigElement.java:84: public MultipartConfigElement(MultipartConfig annotation) {
java/jakarta/servlet/annotation/MultipartConfig.java:30: * multipart/form-data} request are retrieved by a Servlet annotated with {@code MultipartConfig} by calling
java/jakarta/servlet/annotation/MultipartConfig.java:35: * <code>@MultipartConfig()</code> <code>public class UploadServlet extends
java/jakarta/servlet/annotation/MultipartConfig.java:42:public @interface MultipartConfig {
java/jakarta/servlet/http/Part.java:79: * {@link jakarta.servlet.MultipartConfigElement#getLocation()}
java/jakarta/servlet/ServletRequest.java:169: * {@link jakarta.servlet.annotation.MultipartConfig} annotation or a <code>multipart-config</code> element in the
java/jakarta/servlet/ServletRequest.java:196: * {@link jakarta.servlet.annotation.MultipartConfig} annotation or a <code>multipart-config</code> element in the
java/jakarta/servlet/ServletRequest.java:221: * {@link jakarta.servlet.annotation.MultipartConfig} annotation or a <code>multipart-config</code> element in the
java/jakarta/servlet/ServletRequest.java:247: * {@link jakarta.servlet.annotation.MultipartConfig} annotation or a <code>multipart-config</code> element in the
java/jakarta/el/ImportHandler.java:72: servletClassNames.add("MultipartConfigElement");
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:30:import jakarta.servlet.MultipartConfigElement;
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:32:import jakarta.servlet.annotation.MultipartConfig;
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:185: @MultipartConfig
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:248: // to set our own MultipartConfigElement.
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:251: w.setMultipartConfigElement(new MultipartConfigElement("",
test/org/apache/catalina/core/TestSwallowAbortedUploads.java:254: w.setMultipartConfigElement(new MultipartConfigElement(""));
test/org/apache/catalina/core/TestStandardContext.java:31:import jakarta.servlet.MultipartConfigElement;
test/org/apache/catalina/core/TestStandardContext.java:42:import jakarta.servlet.annotation.MultipartConfig;
test/org/apache/catalina/core/TestStandardContext.java:685: // there is no @MultipartConfig
test/org/apache/catalina/core/TestStandardContext.java:713: @MultipartConfig
test/org/apache/catalina/core/TestStandardContext.java:737: // to set our own MultipartConfigElement.
test/org/apache/catalina/core/TestStandardContext.java:738: w.setMultipartConfigElement(new MultipartConfigElement(""));
test/org/apache/catalina/startup/TestMultipartConfig.java:21:import jakarta.servlet.MultipartConfigElement;
test/org/apache/catalina/startup/TestMultipartConfig.java:39:public class TestMultipartConfig {
test/org/apache/catalina/startup/TestMultipartConfig.java:41: public void testNoMultipartConfig() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:44: MultipartConfigElement mce = servlet.getMultipartConfigElement();
test/org/apache/catalina/startup/TestMultipartConfig.java:50: public void testDefaultMultipartConfig() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:55: MultipartConfigElement mce = servlet.getMultipartConfigElement();
test/org/apache/catalina/startup/TestMultipartConfig.java:65: public void testPartialMultipartConfigMaxFileSize() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:70: MultipartConfigElement mce = servlet.getMultipartConfigElement();
test/org/apache/catalina/startup/TestMultipartConfig.java:80: public void testPartialMultipartConfigMaxRequestSize() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:85: MultipartConfigElement mce = servlet.getMultipartConfigElement();
test/org/apache/catalina/startup/TestMultipartConfig.java:95: public void testPartialMultipartConfigFileSizeThreshold() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:100: MultipartConfigElement mce = servlet.getMultipartConfigElement();
test/org/apache/catalina/startup/TestMultipartConfig.java:110: public void testCompleteMultipartConfig() throws Exception {
test/org/apache/catalina/startup/TestMultipartConfig.java:119: MultipartConfigElement mce = servlet.getMultipartConfigElement();
webapps/docs/config/context.xml:270: target servlet isn't marked with the @MultipartConfig annotation
webapps/docs/config/context.xml:363: temporary upload location specified in the <code>MultipartConfig</code>
As the command output shown above, the Tomcat contains the parts that implements the Jakarta Servlet annotations. Here is the relative class diagram:
From above diagram we can see the relationships between the Tomcat classes and the Jakarta Servlet interfaces.